,the ,anatomy of the ,domestic ,fowl ,by ,b4 ,f4 ,kaupp1 ,m4 ,s41 ,d4 ,v4 ,m4 ,poultry ,investigator and ,pathologist in the ,north ,carolina ,experiment ,station1 ,state ,department of ,agriculture1 and the ,state ,college of ,agriculture2 ,formerly ,director of ,anatomy ,laboratory1 ,kansas ,city ,veterinary ,college ,illustrated ,philadelphia and ,london ,w4 ,b4 ,saunders ,company #aiah ,copyright1 #aiah1 by ,w4 ,b4 ,saunders ,company ,,printed ,,in ,,america ,to ,,dan ,t4 ,,gray1 ,b4 ,s41 ,a4 ,b41 ,m4 ,s4 ,,chief1 ,,animal ,,industry ,,division1 ,,north ,,carolina ,,experiment ,,station ,,as ,a ,,token ,,of ,,respect ,,and ,,gratitude ,,this ,,volume ,,is ,,dedicated ,,by ,,the ,,author ,,foreword ,advanced work in the study of poultry husbandry is now being done in this country1 to a greater or less extent1 at all the two score and more ,agricultural and other ,colleges and ,experiment ,stations4 ,from these institutions comes the demand for a text-book on the ,anatomy of the ,domestic ,fowl4 ,no complete text-book on the subject1 up to the present1 has existed4 ,it is with the hope of meeting the demand that this book is published4 ,in supplementing the information gathered from the books and articles listed in the bibliography1 the author has spent much time and effort in obtaining the matter here presented4 ,as this1 however1 is the initial complete text on the subject necessarily much remains to be added and corrected4 ,the author would welcome suggestions and corrections from any one into whose hands the book may come4 ,b4 ,f4 ,,kaupp4 ,,the ,,north ,,carolina ,,state ,,college ,,of ,,agriculture1 ,,west ,,raleigh1 ,,north ,,carolina1 ,september1 #aiah4 ,,contents ,,osteology ,,page ,,osseous ,,structure #ag ,,classification ,,of ,,bones #bj ,,composition ,,of ,,bone #ba ,,skeleton ,,of ,,the ,,fowl #ba ,axial ,skeleton #bc ,cranium and ,face #bc ,occipital #be ,ethmoid #bg ,sphenoid #bh ,frontal #bi ,parietal #bi ,temporal #bi ,premaxilla #ca ,maxilla #cb ,nasal #cb ,lacrimal #cb ,palatine #cc ,pterygoid #cc ,zygomatic #cc ,vomer #cc ,jugal and ,quadrato-jugal #cc ,quadrate #cd ,inferior ,maxilla #cd ,turbinate ,bones #cd ,hyoid #ce ,vertebral ,column #ce ,cervical ,vertebr #ce ,atlas #cg ,axis #cg ,dorsal ,vertebr #ci ,lumbo-sacral ,vertebr #ci ,coccygeal ,vertebr #da ,ribs #da ,sternum #db ,appendicular ,skeleton #dc ,shoulder ,girdle #dc ,fore ,limb #dd ,pelvic ,girdle #dh ,hind ,limb #ej ,,arthrology ,,kinds ,,of ,,joints #ef ,,movements ,,of ,,joints #ef ,,ligamentous ,,structure #eg ,,ligaments ,,of3 ,ear #eh ,jaw #eh ,vertebr #eh ,ribs #ei ,sternum #ei ,shoulder-joint #fa ,elbow-joint #fa ,carpal ,joint #fb ,finger #fd ,pelvis #fe ,hip-joint #fe ,knee-joint #fe ,tibio-metatarsal ,joint #fi ,toes #fi ,,myology ,,kinds ,,and ,,structure ,,of ,,muscles #gj ,,fascia #ga ,,muscular ,,nomenclature #ga ,true ,dermal ,muscles #ga ,dermo-osseous ,muscles #gc ,muscles of the ,head #gf ,muscles of the ,tongue #gi ,cervical ,muscles #ha ,muscles of the ,air ,passages #hf ,superior ,larynx #hf ,inferior ,larynx #hf ,sternal ,muscles #ij ,abdominal ,muscles #ij ,dorsolumbar ,muscles #ib ,coccygeal ,muscles #ic ,costal ,muscles #if ,anterior ,pectoral ,muscles #ii ,pectoral ,muscles #ajj ,muscles of the ,scapular ,region #aja ,muscles of the ,brachial ,region #ajd ,muscles of the ,forearm and ,hand #aje ,digital ,muscles #aji ,muscles of the ,posterior ,limb #aaa ,tibial ,group of ,muscles #aag ,muscles of the ,eye #abd ,muscles of the ,ear #abh ,,functions ,,of ,,muscles #abh ,,splanchnology ,,digestive ,,apparatus #ace ,mouth #ace ,tongue #aci ,pharynx #ada ,glands ,adjacent to ,mouth and ,pharynx #ada ,esophagus #adb ,crop #adb ,stomach #adc ,proventriculus #adc ,gizzard #ade ,small ,intestine #adg ,large ,intestine #aej ,cca #aea ,cloaca #aea ,,course ,,of ,,the ,,food #aeb ,,accessory ,,organs ,,of ,,digestion #aeb ,liver #aec ,pancreas #aee ,spleen #aee ,,abdominal ,,and ,,pelvic ,,cavities #aef ,,peritoneum ,,and ,,mesentery #aef ,,relations ,,of ,,the ,,visceral ,,organs ,,of ,,the ,,domestic ,,fowl #aeh ,,relations ,,of ,,the ,,visceral ,,organs ,,of ,,the ,,baby ,,chick #afe ,,uro-,,genital ,,system #afi ,urinary ,apparatus #afi ,kidneys #afi ,ureter #agd ,male ,generative ,organs #age ,testicles #age ,vas ,deferens #agh ,female ,generative ,organs #agh ,egg #ahj ,oviduct #ahb ,parts of the ,oviduct #ahc ,ligaments of the ,oviduct #ahh ,,ductless ,,glands #aij ,thyroid ,gland #aij ,thymus ,gland #aij ,adrenal ,gland #aia ,,respiratory ,,apparatus #aic ,nostrils and ,nasal ,chambers #aic ,pharynx and ,superior ,larynx #aic ,trachea #aid ,inferior ,larynx #aid ,bronchi and the ,lungs #aie ,air-sacs #aii ,,angiology ,,circulatory ,,apparatus #bjf ,heart #bjf ,structure of the ,heart #bjg ,blood-vessels #bji ,structure of the ,capillaries and ,arteries #bji ,structure of the ,veins #baa ,arterial ,trunks #baa ,branches of3 ,arteria ,brachiocephalica #bac ,arteria ,carotis ,cerebralis ,interna #bad ,arteria ,carotis ,externa #bad ,arteria ,carotis ,facialis #bad ,aorta ,posterior #bbd ,venous ,trunks #bcc ,branches of3 ,ven ,cav ,anteriores #bcd ,vena ,jugularis #bcg ,vena ,occipitalis ,externa #bci ,venous ,sinuses of the ,head #bci ,veins of the ,brain ,cavity #bda ,veins of the ,neck #bdb ,branches of the ,vena ,subclavia #bdc ,veins of the ,dorsal ,region #bdc ,veins of the ,thorax #bdd ,veins of the ,fore ,limb #bde ,branches of the ,iliaca #bdf ,branches of the ,vena ,iliaca ,interna #bdg ,posterior ,vena ,cava #bdg ,veins of the ,posterior ,extremity #bdh ,branches of the ,vena ,cava ,posterior #bdh ,veins of the ,caudal ,region and ,pelvic ,cavity #bej ,veins of the ,truncus ,vena ,iliaca ,communis #beb ,visceral ,veins of the ,posterior ,vena ,cava #beb ,lymphatic ,system #bed ,,blood ,,and ,,its ,,functions #beg ,,fate ,,of ,,the ,,erythrocyte #bfa ,,neurology ,,nervous ,,system #bfd ,cranial ,nerves #bfe ,olfactorius #bfe ,opticus #bfg ,motoris ,oculi #bfg ,patheticus #bfh ,trifacialis #bfh ,abducentes #bgj ,facialis and ,acousticus #bga ,vagus ,group #bgb ,glosso-pharyngeus #bgb ,vagus or ,pneumogastricus #bgc ,accessorius ,spinalis #bgd ,hypoglossus #bgd ,spinal ,cord #bge ,structure of the ,cord #bge ,structure of the ,nerve ,trunks and ,ganglia #bgg ,spinal ,nerves #bha ,brachial ,plexus #bhb ,lumbo-sacral or ,crural ,plexus #bhe ,brain #bhh ,coverings of the ,brain #bhh ,structure of the ,brain #bhi ,divisions of the ,brain #bij ,sympathetic ,nervous ,system #big ,functions of the ,nervous ,system #cjj ,,esthesiology ,,sense ,,organs #cjc ,sight #cjc ,hearing #cje ,smell #cjg ,taste #cjg ,touch #cjg ,,structure ,,of ,,appendages #cji ,,embryology ,,spermatogenesis #cah ,o,,genesis #cai ,,fertilization #cai ,,outline ,,for ,,laboratory ,,study ,,of ,,the ,,chick #ccj ,living ,embryo #ccj ,preparation for ,study of ,entire ,embryos and ,sections #ccj ,points to be ,observed in the ,study #ccb ,,derivatives ,,of ,,the ,,germ-,,layers #cdb ,,preparation ,,of ,,structures ,,for ,,study #cdc ,directions for ,dissecting ,muscles #cdc ,directions for ,study of the ,viscera #cdd ,directions for ,study of the ,arteries #cde ,study of the ,structure of ,bones #cdf ,special ,technic for ,dissection of ,cranial and ,spinal ,nerves #cdg ,directions for ,study of ,soft ,structures #cdg ,to ,stain ,sections of ,liver for ,study of ,kupffer ,cells #cdi ,to ,prepare ,anatomical ,specimens for ,museum #cdi ,to ,make ,specimens ,transparent #cej ,,equipment ,,for ,,the ,,dissection ,,laboratory #cea ,,bibliography #cec ,,index #cee ,,anatomy ,,of ,,the ,,domestic ,,fowl ,,osteology ,osseous ,structure4--,bone is structurally modified connective tissue which has become hard by being impregnated with calcium salts4 ,kinds of ,bone ,tissue4--,there are two kinds of bone tissue3 substantia compacta1 or compact bone tissue2 and substantia spongiosa1 or spongy1 cancellous bone tissue4 ,compact ,bone ,tissue4--,the compact bone tissue forms the hard outer layer of all bones4 ,it is thickest in the shaft and becomes thin toward the extremities4 ,through the compact bone tissue approximately parallel with the longitudinal axis of the bone1 run canals called ,haversian canals1 through which pass blood and lymph vessels for the nourishment of the bone and nerves4 ,the ,haversian canals are surrounded by concentric lamell4 ,the spaces between the cylinders thus formed are filled with interstitial lamell2 and both the exterior surface of the bone and the interior surface surrounding the medullary canal1 are built up of peripheral1 or circumferential lamell4 ,between the lamell1 somewhat irregularly placed1 are minute reservoirs1 called lacun1 which contain bone corpuscles4 ,from the lacun radiate minute canals1 or canaliculi1 which maintain circulation through the bone substance1 and which communicate with the ,haversian canals4 ,complex anastomoses exist among the canaliculi4 ,still other channels for the passage of blood-vessels are ,volkmann's canals which pierce the peripheral lamell1 thus allowing vessels to pass from the periosteum to the ,haversian canals4 ,similar channels afford communication between the inner ,haversian canals and the medullary cavity4 ,the entire structure composed of an ,haversian canal1 its surrounding lamell1 lacun1 and canaliculi1 with their contained vessels1 is called an ,haversian system4 ,cancellous ,bone ,tissue4--,the cancellous bone tissue forms the bulk of the short1 flat1 and irregular bones and of the extremities of the long bones4 ,it consists of delicate bony plates and spicules1 which intercross in various directions4 ,the spaces between these plates and spicules1 called cancelli1 are occupied by marrow except in the bones that are pneumatic4 ,the blood-vessels1 lymphatics1 and nerves course through this marrow but are not arranged in an ,haversian system4 ,illustration3 ,,fig4 #a4--,longitudinal section of compact bone of the femur of the hen4 #a1 ,haversian canals4 #b1 ,lacun with their canaliculi4 ,the ,periosteum4--,covering the surface of bone1 except at the articular surface where it is covered with cartilage1 is a membrane1 the periosteum1 which consists of two layers3 an outer1 fibrous1 protective layer1 and an inner1 cellular1 osteogenic layer4 ,the outer layer consists principally of white fibrous tissue4 ,the inner layer contains many more connective-tissue cells1 which gradually become more closely aggregated as we proceed toward the osseous surface2 but there is no sharply defined line of demarcation between the two periosteal layers4 ,illustration3 ,,fig4 #b4--,transverse section of compact bone of the femur of the hen4 #a1 ,the lacun and canaliculi4 #b1 ,the periosteum4 ,illustration3 ,,fig4 #c4--,transverse section of compact bone of the femur of the hen showing the lacun and canaliculi under high magnification4 ,the periosteum is firmly attached to the bone by trabecul of fibrous tissue1 called the fibers of ,sharpey4 ,these fibers of ,sharpey penetrate the bone at right angles to its surface and carry blood-vessels4 ,marrow4--,there are two kinds of marrow3 yellow1 or medulla ossium flava1 and red1 or medulla ossium rubra4 ,the yellow marrow occurs in all bones except the femur and proximal portion of the tibia of adult fowls4 ,it is composed of a network of fibrous tissue carrying blood-vessels1 fat cells1 and myelocytes1 or marrow cells4 ,the red marrow is found throughout the femur and the proximal portion of the tibia1 and in a few of the pelvic bones and vertebr in the adult fowl1 and in certain other bones of the baby chick4 ,red marrow consists of a delicate network of connective tissue supporting a dense capillary plexus1 a small amount of fat1 and numerous cells4 ,the cellular elements of red marrow consist of marrow cells which contain large nuclei and possess ameboid movement1 red blood cells1 giant cells containing one or more nuclei1 and various kinds of leucocytes1 including eosinophiles1 mast cells1 and also osteoclasts4 ,growth of ,bone4--,in the baby chick1 only the shaft and a portion of the extremities of the long bones are thoroughly ossified1 the extreme ends1 and of the femur most of the articular head1 being cartilaginous4 ,the bones grow in length by an increase in the cartilage1 the cartilage gradually becoming ossified4 ,growth in diameter is accomplished by the constant deposition of new layers of bone beneath the periosteum4 ,during this process the osteoclasts absorb the bone from within4 ,the formation of the marrow cavity is thus effected4 ,classification of ,bones4--,the bones of the fowl are classified as long1 short1 flat1 and irregular4 ,long ,bones4--,the long bones occur in the legs and wings1 where they serve as levers to sustain weight and make locomotion possible4 ,a long bone consists of a shaft and two extremities4 ,the superior is called the proximal and the inferior the distal extremity4 ,the expanded articular surfaces in forming joints with adjoining bones afford ample space for the attachment of ligaments4 ,the shaft is cylindrical and hollow4 ,short ,bones4--,short bones occur in the feet and in the wings4 ,their structure is similar to that of the long bones4 ,flat ,bones4--,the flat bones occur where extensive protection is needed1 as in the cranial region2 or where large surface for muscular attachments is needed1 as in the costal and pelvic regions4 ,flat bones are made up of two thin layers of compact bone with a variable amount of cancellous tissue interposed4 ,irregular ,bones4--,the irregular bones include the vertebr1 the patell1 and the carpal bones4 ,composition of ,bone4--,bone consists of organic and inorganic matter4 ,organic matter gives toughness and elasticity to the bone1 and inorganic matter hardness4 ,the organic substance of bone is called ossein4 ,when boiled in water ossein is resolved into gelatin4 ,the following tables#a give the results of an analysis of the femur1 fresh1 of a mature hen4 ,footnote #a3 ,grateful acknowledgment is hereby made to ,dan ,m4 ,mc,carty1 ,chemist1 ,animal ,industry ,division1 ,north ,carolina ,agricultural ,experiment ,station1 for this analysis4 ,fresh femur3 ,water #ah4bc per cent4 ,dry matter #ha4gg per cent4 ,dry matter3 ,organic matter #fc4ji parts ,inorganic matter #ah4fh parts ,salts in dry matter3 ,calcium #f4igj per cent4 ,magnesium #j4bhc per cent4 ,potassium #j4jjd per cent4 ,sodium #j4bgf per cent4 ,iron #j4jbj per cent4 ,phosphorus #c4baj per cent4 ,sulphur #j4jhe per cent4 ,chlorine #j4ebj per cent4 ,carbon dioxid #j4eej per cent4 ,the inorganic matter of the femur of the hen consists of #ah4fh parts or #bb4hd per cent4 of dry matter1 and the organic matter of #gg4af per cent4 ,stated in other words the femur1 including its contained marrow1 consists of organic and inorganic matter in the ratio of #c4d1 approximately1 to #a4 ,the ,skeleton of the ,fowl4--,the skeleton of a bird is remarkable for the rapidity of its ossification4 ,it is worthy of note that other parts of the bodies of adult birds also become ossified4 ,among such parts are the tendons of the muscles of the legs1 of the feet1 and of the neck2 the plates of the corneal margin of the sclerotic tunic of the eye2 and the stapes of the ear4 ,ossification in birds at the attachments of the semi-lunar valves of the aorta and of the pulmonary artery has been reported by ,owen4 ,the bony structure is compact1 and the bones contain a greater proportion of phosphate of lime than do the osseous structures of mammals4 ,especially is this the case in those parts of the skeleton which are permeated by air4 ,,the ,,divisions ,,of ,,the ,,skeleton 7 ,the ,skull 7 ,cranium 7 7 ,face ,the ,axial skeleton 7 7 ,cervical region 7 7 ,dorsal region 7 ,ribs 7 ,the ,vertebral column 7 7 ,sternum 7 ,lumbar region 7 ,sacral region 7 ,coccygeal region 7 ,scapula 7 ,shoulder girdle 7 ,coracoid 7 7 ,clavicle 7 7 7 ,arm 7 ,humerus 7 7 7 ,fore limb 7 ,forearm 7 ,radius 7 7 7 ,ulna 7 7 7 7 7 ,carpus ,the ,appendicular skeleton 7 7 ,hand 7 ,metacarpus 7 7 ,phalanges 7 7 ,pelvic girdle 7 ,ilium 7 7,hip bone7 7 ,ischium 7 7 ,pubis 7 7 7 ,thigh 7 ,femur 7 ,hind limb 7 7 ,leg 7 ,tibia 7 7 ,fibula 7 7 ,foot 7 ,metatarsus 7 ,phalanges ,the bodies of birds contain many air reservoirs to make them light that flying may be more easy4 ,many bones have their weight in proportion to size and strength thus greatly reduced4 ,in very young birds the cavities of bones contain1 instead of air spaces1 loosely arranged red marrow1 which is in most bones later absorbed4 ,the air reservoirs in bones are most capacious in the best flyers4 ,in the non-flyers more of the bones retain their red marrow4 ,the bones supplied with air spaces are relatively larger than in mammals1 and are provided with small transverse osseous columns which cross in different directions and from side to side4 ,these cross beams give stability to the thin wall of the bone4 ,the membranes lining these cavities are very vascular4 ,,the ,,axial ,,skeleton ,,the ,,skull ,the skull is divided into the cranial and facial portions4 ,in these parts we find present #ca bones3 one occipital1 two parietal1 two frontal1 one ethmoid1 one sphenoid1 and two temporal2 all of which constitute the cranial group2 two premaxillary1 two maxill1 two nasal1 two lacrimal1 two palatine1 two pterygoid1 two zygomatic1 one vomeral1 the two jugal1 and two quadrato-jugal1 which constitute the facial group2 two quadrati and one inferior maxillary1 which constitute the inferior jaw group4 ,the peculiarities of the skull are the long os incisivum and the single condyle located on the occipital bone just below the foramen magnum4 ,the condyle articulates with the atlas4 ,the head of the bird is small in proportion to the size of the body1 and in front it is conical in shape4 ,,the ,,cranium ,the cranial cavity1 or cavum cranii1 incloses the brain with its membranes and vessels4 ,the dorsal wall1 or roof1 is formed by the frontal and the parietal bones4 ,in the median line of the cerebral portion is the internal parietal crest4 ,the roof of the cerebellar portion is marked centrally by a groove4 ,the posterior wall of the cerebellum is formed by the occipital bone4 ,the lateral wall is formed chiefly by the temporal bone4 ,it is marked by a ridge which divides the cavity into the cerebral and cerebellar compartments4 ,the cerebral portion is marked by a depression which receives the optic lobes4 ,a crest divides this cavity from the optic portion4 ,the walls are marked by digitations and vascular grooves4 ,illustration3 ,,fig4 #d4--,the skeleton of the domestic fowl4 #a1 ,os incisivum4 #b1 ,external nasal opening4 #c1 ,os nasale4 #d1 ,os lachrymale4 #e1 ,lamina perpendicularis4 #f1 ,os dentale4 #g1 ,os palatine4 #h1 ,os quadrato-jugal4 #i4 ,os pterygoideum4 #aj1 ,os quadratum4 #aa1 ,os articulare4 #ab1 ,external auditory canal4 #ac1 ,atlas4 #ad1 ,os carpi radiale4 #ae1 ,radius4 #af1 ,first finger4 #ag1 ,os metacarpus4 #ah1 ,second finger4 #ai1 ,third finger4 #bj1 ,os carpi ulnare4 #ba1 ,ulna4 #bb1 ,humerus4 #bc1 ,thoracic vertebr4 #bd1 ,scapula4 #be1 ,os ilium4 #bf1 ,foramen ischiadicum4 #bg1 ,caudal vertebr4 #bh1 ,pygostyle4 #bi1 ,foramen obturatum4 #cj1 ,os ischium4 #ca1 ,processus uncinatus4 #cb1 ,vertebral rib4 #cc1 ,os claviculum or furculum4 #cd1 ,os coracoideum4 #ce1 ,os femoris4 #cf1 ,os pubis4 #cg1 ,body of sternum4 #ch1 ,lateral internal process of sternum4 #ci1 ,costal process of sternum4 #dj1 ,sternal crest1 cristi sterni1 or keel of breast-bone4 #da1 ,sternal rib4 #db1 ,lateral external process of sternum4 #dc1 ,os fibula4 #dd1 ,xyphoid process of sternum4 #de1 ,internal notch4 #df1 ,os patella4 #dg1 ,os tibia4 #dh1 ,os metatarsus4 #di1 ,second toe4 #ej1 ,fourth toe4 #ea1 ,os metatarsale4 #eb1 ,first toe4 #ec1 ,second toe4 #ed1 ,second phalanx of second finger4 #ee1 ,os metacarpus4 #ef1 ,air opening in humerus4 #eg1 ,hypocledium4 #eh1 ,external notch4 #ei1 ,cervical vertebr4 #fj1 ,foramen oblongum4 ,the ventral wall1 floor1 or basis cranii interna1 may be regarded as forming five foss4 ,these are3 one anterior1 one middle1 one posterior1 and two lateral4 ,the anterior fossa supports the frontal and olfactory parts of the cerebrum4 ,it lies at a higher level than the middle fossa4 ,the middle fossa1 or fossa cranii media1 is circular in outline and extends into the lateral foss which lodge the olfactory lobes4 ,just back of the middle fossa is the sulla turcica1 upon which rests the pituitary body4 ,the posterior fossa1 or fossa cranii posterior1 lodges the medulla oblongata4 ,bones of the ,cranium 7,figs4 #d1 #f1 #g1 and #h74--,the bones of the cranium fuse early in the chick's life4 ,the sutures uniting the bones can usually be seen in the fetus or in the baby chick soon after it emerges from the shell4 ,the major portion of the cranial bones become entirely fused4 ,each cranial and each facial bone ossifies from a distinct center or centers4 ,the cavity for the cerebrum is much larger than the cavity for the cerebellum4 ,the cranial cavities in birds are relatively larger than in mammals4 ,the bones are designated as in mammals4 ,there are three single bones1 the occipital1 the ethmoid1 and the sphenoid4 ,those in pairs are the frontal1 the parietal1 and the temporal4 ,the ,occipital4 ,location4--,the occipital bone or os occipitale1 is situated at the posterior part of the cranium1 of which it forms the posterior wall4 ,this part is called the base of the cranium4 ,the occipital bone articulates with or touches inferiorly1 the sphenoid1 laterally1 the temporal1 and superiorly1 the parietal4 ,development4--,the occipital bone is developed from four centers of ossification2 the dorsal1 or os occipitale superius1 two lateral1 or ossa occipitales laterales1 and the ventral1 or os occipitale inferius1 all of which may be seen distinct in the baby chick 7,fig4 #e1 ,part ,,ii1 ,no4 #a74 ,illustration3 ,,fig4 #e4--;,bones of the head and vertebra4 ,part ,i4--#a1 ,the cranium4 #b1 ,the skull cap4 #c1 ,the ethmoid bone4 #d1 ,the inferior maxilla4 #e1 ,the palatine bone4 #f1 ,the quadrato-jugal4 #g1 ,the jugal4 #h1 ,the superior maxilla4 #i1 ,the premaxilla4 #aj1 ,the horny covering for the premaxilla4 #aa1 ,the horny covering for the os dentale4 #ab1 ,the os quadratum4 #ac1 ,the nasal bone4 #ad1 ,the pterygoid4 ,part ,,ii4--#a1 ,the os occipitale 7#a1 dorsal2 #b1 two lateral2 #c1 ventral portions and #d1 foramen magnum74 #b1 ,the fourteen cervical vertebr4 7#a1 atlas2 #b1 axis74 #c1 ,the seven dorsal vertebr4 #d1 ,the fourteen lumbo-sacral vertebr4 #e1 ,the seven coccygeal vertebr4 #f1 ,the pelvis 7#a1 ilium2 #b1 ischium2 #c1 pubis2 #d1 cotyloid cavity or acetabulum74 #g1 ,the vertebral column complete from the baby chick4 #h1 ,the parietal bone4 #i1 ,the temporal bone4 #aj1 ,the frontal bone4 ,description4--,in the center of the occipital bone is the foramen magnum4 ,through this foramen the spinal cord extends into the cranial cavity and connects with the medulla oblongata4 ,the occipital bone has a single condyle1 which is located just below the foramen magnum and articulates with the atlas4 ,at the base of the condyle a small subcondyloid fossa receives the body of the atlas during extreme flexion of the head4 ,in the center of the lateral wing of the occipital bone there is a small foramen through which passes the hypoglossal nerve4 ,somewhat laterally from this foramen there is an opening through which the vagus1 or pneumogastric nerve passes4 ,laterally from these is the canalis caroticus et jugularis4 ,between the os occipitale superius1 or dorsal portion1 and the ossa parietalia is a space to which ligaments are attached1 called the fontanel4 ,illustration3 ,,fig4 #f4--,view of the frontal region of the skull of a hen4 #a1 ,parietal4 #b1 ,frontal4 #c1 ,nasal4 #d1 ,premaxilla4 #e1 ,temporal4 #f1 ,inferior jaw4 #g1 ,jugal bone4 ,the ,ethmoid4 ,location4--,the ethmoid1 or os ethmoidale1 forms the anterior wall of the cranium1 and the orbital septum4 ,it is related anteriorly with the vomeral1 superiorly with the nasal and frontal1 posteriorly with the temporal1 and inferiorly with the sphenoid1 and palatine4 ,description4--,the ethmoid consists of a perpendicular and a horizontal lamina4 ,the perpendicular lamina1 located between the orbital cavities1 is called the septum interorbitale4 ,on each side of the septum interorbitale and near the superior orbital roof are two foramina for the passage of the olfactory nerves4 ,in the horizontal plate1 which forms the anterior cranial wall1 are located the optic foramina through which pass the optic nerves4 ,illustration3 ,,fig4 #g4--,side view of the skull of a hen4 #a1 ,lamina perpendicularis4 #b1 ,foramen for the passage of the nerve of smell4 #c1 ,foramen for the passage of the optic nerve4 #d1 ,nasal bone4 #e1 ,external nasal opening4 #f1 ,premaxilla4 #g1 ,os dentale4 #h1 ,superior maxilla4 #i1 ,os jugal4 #aj1 ,os quadrato-jugal4 #aa1 ,os quadratus4 #ab1 ,pterygoideus4 #ac1 ,os articulare4 #ad1 ,inferior maxilla4 #ae1 ,temporal4 #af1 ,external auditory canal4 #ag1 ,parietal4 #ah1 ,frontal4 #ai1 ,palatine4 #bj1 ,orbital process1 posterior to which is the processus zygomaticus4 #ba1 ,interorbital foramen and optic foramen for passage of optic nerve4 #bb1 ,attachment for inferior oblique2 #bc1 for superior oblique2 #bd1 for levator palpebr superioris2 #be1 for internal rectus2 #bf1 for superior rectus2 #bg1 for external rectus2 #bh1 for inferior rectus2 #bh1 for inferior rectus2 #bi1 for depressor palpebr inferioris2 #cj1 for orbicularis palpebrarum2 #ca1 for tensor tympani2 #cb1 for circumconcha4 ,the ,sphenoid4 ,location4--,the sphenoid1 or os sphenoidale1 forms the floor of the cranial cavity and articulates with or touches posteriorly the occipital1 laterally the temporal1 and anteriorly the palatine1 and ethmoid4 ,description4--,the sphenoid bone1 the largest part of the cranial floor1 is formed by the fusion of the nasal and the cranial parts4 ,it is a three-cornered bone with two1 thin1 broad wings4 ,these wings are divided into two portions1 orbital wings1 or al orbitales1 and temporal wings1 or al temporales4 ,the temporal wing forms a cover for the ,eustachian tube trumpet1 and for the canal coming from the sella turcica1 which latter gives passage to the intracranial carotid artery4 ,the orbital wing forms the lower portion of the posterior wall of the orbital cavity1 and lies directly before the os petrosum or temporal bone where the second and third branches of the fifth pair of cranial nerves emerge from the cranial cavity4 ,anteriorly the sphenoid has a foramen for the passage of the ,eustachian tube1 the tuba auditiva1 and also a sharp-pointed projection1 the nasal portion1 called the rostrum4 ,the ,frontal4 ,location4--,the frontal bones1 or ossa frontales1 two in number1 form the forehead1 a portion of the nose1 and a portion of the roof of the orbital cavities4 ,they are related posteriorly with the parietal1 laterally with the temporal and zygomatic1 and anteriorly with the nasal and premaxillary4 ,they touch inferiorly the ethmoid4 ,description4--,each of these bones has a processus orbitalis which is seen at the outer margin of the posterior and upper orbital wall and just in front of the zygomatic process of the squamous portion of the temporal4 ,the frontal bone forms the anterior portion of the superior wall of the cranial cavity4 ,the two bones are thin1 flat1 and meet at the median line of the forehead4 ,the external surface is convex4 ,the inner surface has a ridge located longitudinally and in the center the bone becomes narrow anteriorly4 ,the ,parietal4 ,location4--,the parietal bones1 or ossa parietalia1 two in number1 form the posterior part of the roof of the cranial cavity4 ,they meet in the median line and are related posteriorly with the occipital1 anteriorly with the frontal1 and laterally with the temporal bones4 ,description4--,the parietal bones are short and very broad 7,fig4 #e1 ,part ,,ii1 ,no4 #h74 ,each bone is quadrilateral in outline and has two surfaces1 four borders and four angles4 ,the external parietal surface is convex and smooth and the internal1 cerebral surface is concave4 ,the ,temporal4 ,location4--,the temporal bones1 or ossa temporales1 two in number1 are located at the lateral portion of the cranium1 and aid in the formation of the cranial wall4 ,the temporal bone is related posteriorly with the occipital1 superiorly with the parietal and frontal1 externally with the quadratus1 anteriorly with the ethmoid1 and inferiorly with the sphenoid4 ,description4--,the temporal bones consist of the fused squamous and petrous temporals2 they contain the essential organs of hearing4 ,illustration3 ,,fig4 #h4--;,inferior view of the skull of a hen4 #a1 ,occipital4 #b1 ,foramen magnum4 #c1 ,occipital condyle and just below the basi-occipital4 #d1 ,foramen for the passage of the hypoglossal nerve4 #e1 ,foramen for the passage of the vagus4 #f1 ,canalis caroticus and jugulare4 #g1 ,sphenoid4 #h1 ,temporal wings of the sphenoid4 #i1 ,foramen auditiva4 #aj1 ,os articulare4 #aa1 ,os angulare4 #ab1 ,vomer4 #ac1 ,os dentale4 #ad1 ,pterygoid4 ,the squamous portion of the temporal bone possesses the long thin zygomatic process sometimes called the posterior orbitalis4 ,it forms a small flattened tongue1 directed forward1 sometimes free1 and at other times united by its superior border to the summit of the orbital process4 ,this is especially true in the turkey4 ,this process is seen near the lower outer portion of the posterior orbital wall4 ,the squamous portion is also provided antero-laterally with an articular facet which articulates with the quadrate bone4 ,the large portion of the temporal bone lies on the side of the cranium superior to the ala sphenoida temporale4 ,it extends outward and anteriorly over the rims of the petrosum and ala sphenoida orbitale4 ,the squamous part forms the upper three-fourths of the cochlea1 the inner auditory canal1 the upper part of the fenestra ovalis1 the anterior vertical and the outer semicircular canal1 and the lower part of the posterior vertical semicircular canal4 ,the petrous portion forms the posterior wall of the foramen ovale and the fenestra ovalis in which lies the columella4 ,the fenestra ovalis and the fenestra rotunda are the only two entrances into the labyrinth4 ,in this region may be seen the fusion line between the os petrosum and the os occipitale4 ,superiorly and posteriorly the petrous portion touches the external parietalia and occipitalis2 infero-laterally it unites with the basi-sphenoid4 ,the outer rim of the foramen ovale is broadened by the ala sphenoida and mesially by the basi-sphenoid4 ,this foramen gives exit to the second and third divisions of the fifth pair of cranial nerves4 ,the lateral surface of the temporal bone presents a short tube1 the external acoustic process1 or processus acusticus externus1 to which is attached the concha of the ear4 ,the process is directed outward4 ,its lumen1 the external acoustic meatus1 or meatus acusticus externus1 conducts to the cavity of the middle ear in the bare skull1 but is separated from it by the tympanic membrane in the natural state4 ,,bones ,,of ,,the ,,face ,the bones of the face1 or ossa faciei1 are the premaxillary1 or upper mandible1 the maxill1 the nasal1 the lacrimal1 the palatine1 the pterygoid1 the zygomatic1 the vomeral1 the jugal and the quadrato-jugal4 ,the vomer is single1 the others are paired4 ,in the inferior maxillary group there are the quadrati1 and the inferior maxillary1 or lower mandible4 ,the turbinated and hyoid bones are also discussed with the bones of the face4 ,the beak consists of the anterior portion of the upper and lower mandibles which are covered with a horny structure4 ,the ,premaxilla4 ,location4--,the premaxill1 or ossa incisiva1 or mandibular structures1 are located in the extreme anterior facial region4 ,description4--,the premaxill are long and the anterior end is pointed4 ,each consist of two lateral halves which become fused before the chick is hatched4 ,they partly circumscribe the openings into the nose4 ,this bone is the base of the upper portion of the beak and determines its form4 ,it forms the anterior walls of the nasal cavity4 ,it has between the nasal bones1 two processes which extend back to the anterior point of the cerebral cavity4 ,the posterior part of the incisivum and nasale are flat1 thin1 and elastic4 ,the extensions then are the processus maxillaris1 the processus palatinus1 and the processus frontalis1 the first of which forms part of the jaw rim1 the second1 which aids in forming the gum plate1 and the last which reaches to the anterior portion of the cranial wall4 ,the ,maxilla4 ,location4--,the superior maxillaries1 or ossa maxillares1 two in number1 form the floor of the upper beak1 a part of the palatine roof and nasal walls4 ,each maxilla borders laterally the premaxilla and the nasal2 inferiorly1 the anterior point of the palatine2 and posteriorly1 the jugale4 ,description4--,the maxill are thin1 flat1 bones4 ,they have three borders and three angles4 ,the palatine processes of the two bones do not meet in the median line1 which results in a cleft in the median palatine region4 ,the bone-like gums are formed partly by the palatine processes but more largely by lateral wings of the os incisivum4 ,each maxilla has posteriorly a yoke-like extension1 superiorly a small extension1 and also a palatine process4 ,the latter articulates by a facet with the vomer4 ,the ,nasal4 ,location4--,the nasal bones1 or ossa nasalia1 two in number1 are located in the lateral facial region4 ,the nasal bone articulates posteriorly with the frontal2 laterally1 on the inner border1 with the processus frontalis of the premaxilla1 and on the outer border with the lacrimal2 and inferiorly with the premaxilla1 maxilla1 jugale1 and vomer4 ,description4--,the nasal bone1 or os nasale1 is broad1 flat1 and elastic and forms the posterior wall of the nasal opening4 ,under this bone is located the infraorbital sinus4 ,there are three extensions3 first1 the processus intermaxillaris1 which forms the upper wall of the nasal cavity2 second1 the processus maxillaris anterior1 directed downward and forward1 which fuses with the maxillary bone and forms the posterior rim of the nasal cavity2 and third1 a posterior processus frontalis1 which lies parallel with the ethmoid4 ,the ,lacrimal4 ,location4--,the lacrimal bones1 or ossa lacrimalia1 two in number1 are located at the outer border and at the junction of the processus frontalis of the nasal1 with the frontal bone4 ,description4--,the lacrimal bone is small1 and rather filiform4 ,they become fused with the nasal and the frontal bones1 forming part of the margin of each4 ,the ,palatine4--,location4 ,the palatine bones1 or ossa palatina1 two in number1 enter into the formation of the inner part of the bony gum and hard palate1 or roof of the mouth4 ,they form the support for the hard palate4 ,each palatine articulates posteriorly with the rostrum1 or nasal portion of the sphenoid1 and with the pterygoid2 and anteriorly with the maxilla4 ,description4--,the palatine bone is curled posteriorly and is thin at the upper portion and thick at the lower border4 ,anteriorly it has a long rather filiform projection4 ,the ,pterygoid4 ,location4--,the pterygoid bones1 or ossa pterygoidea1 two in number1 are located back of the region of the posterior nares4 ,they extend diagonally outward and backward from the median region of the sphenoid rostrum to the quadrate bone4 ,they articulate anteriorly with the sphenoid rostrum and the palatine1 and posteriorly with the quadrate4 ,description4--,the pterygoid bones are slender and cylindrical1 and are expanded at the ends into an articular facet4 ,the ,zygomatic4 ,location4--,the zygomatic1 or ossa zygomatica1 two in number are situated below the orbital cavity and extend from the maxilla to the quadrate bone4 ,description4--,the zygomatic is small1 slender1 rod-shaped1 and forms the lateral portion of the upper jaw4 ,the anterior portion of the zygomatic represents the jugal and is fused with the maxilla and with the anterior processus maxillaris of the nasal bone1 the maxilla1 and the posterior portion1 the quadrato-jugal1 which articulates with the quadrate bone4 ,the ,vomer4 ,location4--,the vomer is located in the median nasal septum4 ,it articulates with the rostrum of the sphenoid1 being connected to it by a mass of ligaments4 ,it touches anteriorly the posterior portion of the maxilla4 ,description4--,the vomer is a median bone and aids in the formation of the septum nasi4 ,it consists of a thin plate1 thickest posteriorly and diminishing toward the anterior edge4 ,the ,jugal and ,quadrato-jugal4--,the jugal and quadrato-jugal are united forming a long slender cylindrical bone called the zygomatic1 lying at the outer side of the upper jaw4 ,they have been described under zygomatic1 which see4 ,the ,quadrate4 ,location4--,the quadrate bones1 or ossa quadrata1 two in number1 are located antero-laterally to the temporal bones4 ,each articulates inferiorly with the posterior articular portion1 or pars articulare1 of the inferior maxilla and infero-laterally with the quadrato-jugalare portion of the zygomatic4 ,it articulates antero-internally with the pterygoid and supero-posteriorly with the temporal4 ,description4--,the quadrate bone is anvil-like in shape4 ,it has an anterior process1 the orbital process1 for muscular attachments1 and posteriorly it affords attachment to the ear drum4 ,the ,inferior ,maxilla4 ,location4--,the inferior maxilla1 lower jaw1 or os maxillare inferius1 also called the mandibular bone1 or pars dentis1 is analogous to the lower jaw of mammals4 ,it articulates posteriorly with the quadrate bone4 ,description4--,the inferior maxilla is the largest bone of the face4 ,it is made up of a right and a left limb which are separate in the fetus and which unite subsequently anteriorly1 forming the inferior portion of the beak4 ,each limb of the jaw is developed from five elements3 the pars articularis1 which forms the jaw-joint and1 expanded1 articulates with the quadrate bone2 the pars angularis1 lying just in front of the pars articularis2 the pars supra-angularis1 a slender bone lying just above the angularis2 the splenial1 a thin plate of bone1 lying along the inner surface of the mandible2 and the pars dentalis1 which forms the anterior portion of the jaw4 ,the ,turbinate ,bones4 ,location4--,the turbinate bones1 or ossa turbinata1 six in number1 are attached to the lateral walls of the nasal cavity 7,fig4 #bf1 ,no4 ,a1 #a and #b74 ,in each nasal cavity there are three turbinate bones1 one anterior and two posterior4 ,of the two posterior the upper one lies supero-posterior to the inferior one4 ,the turbinate bones are attached to the lateral nasal walls1 project into the cavity and thus greatly diminishing its extent4 ,description4--,each turbinate bone is composed of a very thin lamina1 finely cribriform in many places1 and in the fresh state1 covered on both sides with mucous membrane4 ,these bones are curled and partly membrano-cartilaginous structures which give greater surface in the nasal passage for mucous membrane in which the olfactory nerve terminal filaments are distributed4 ,the ,nasal ,cavity4--,the nasal cavity1 or cavum nasi1 is a longitudinal passage which extends through the upper part of the face4 ,it is divided into right and left halves by a median septum nasi4 ,its walls are made up of the premaxilla1 maxilla1 nasal1 vomer1 and palatine bones4 ,the ,hyoid ,bone4 ,location4--,the hyoid bone1 or os hyoideum1 is situated chiefly between the rami of the mandible1 but its upper part extends around the outer margin of the base of the skull4 ,the hyoid bone does not articulate with any bones of the skull1 but is firmly attached by strong fibrous structure4 ,description4--,the hyoid bone consists of the following parts3 the body1 or basi-hyal1 which is subcylindrical and presents in front a trochlear articular surface1 convex transversely1 and concave vertically for articulation with the ewer-shaped portion of the glosso-hyal4 ,the anterior free portion1 or lingual process1 is called the glosso-hyal1 or entoglossal bone4 ,the lingual process gives support to the muscular and fibrous structures of the tongue4 ,on either side of the basi-hyal there is a limb passing posteriorly along the side of the superior larynx1 extending upward along the outer border of the occipital bone4 ,this is the cornu of the os hyoideum and is divided into two elements1 first1 the basi-branchial which is bone and articulates with the basi-hyal1 and the second1 the cerato-branchial1 cartilaginous in structure4 ,in the center and projecting backward from the body of the os hyoideum is a spur process called the uro-hyal1 partly bony and partly cartilaginous1 and which rests upon the superior larynx4 ,,the ,,vertebral ,,column ,the vertebral1 or spinal column consists of #db bones1 as shown in the following table3 ,cervical region #ad ,dorsal region #g ,lumbo-sacral region #ad ,coccygeal region #g ---- ,total #db ,many of the bones of the dorsal and lumbo-sacral regions do not have free articulations4 ,the cervical and coccygeal alone have free movements4 ,the ,cervical ,vertebr 7,fig4 #d1 ,no4 #ei2 ,fig4 #e1 ,part ,,ii1 ,no4 #b74 ,location4--,the cervical vertebr form the neck of the fowl4 ,illustration3 ,,fig4 #i4--,os hyoidum and tongue muscles4 #a1 ,glosso-hyal4 #c1 ,basi-hyal4 #d1 ,basi-branchial element of the cornua4 #e1 ,cerato-branchial element of the cornua4 #f1 ,uro-hyal or spur process4 #g1 ,genio-hyoideus4 #h1 ,cerato-hyoideus showing the slender tendon4 #i1 ,hyoideus transversus4 #aj1 ,hyoideus transversus4 ,description4--,the long cervical section of the spinal column is ,s-shaped and is made up of fourteen vertebr4 ,the anterior segments move freely forward1 the middle ones backward and the posterior ones forward1 allowing the ,s-shaped curve of the neck4 ,the neck is flexible so that it is possible for the beak to reach the coccygeal oil gland4 ,the bird is enabled to reach the feathers on all parts of the body to cleanse and oil them4 ,the ,atlas4 ,location4--,the first cervical vertebra is called the atlas4 ,anteriorly it articulates with the single condyle of the occipital bone4 ,posteriorly it articulates with the axis1 or second cervical vertebra4 ,description4--,the atlas is the smallest of the cervical vertebr and is ring-shaped4 ,the anterior articular surface1 half-moon in shape1 forms a deep articular cavity4 ,the joint1 called a ball-and-socket joint1 makes possible movements in all directions4 ,the condyle of the occiput also touches an articular end of the odontoid process of the axis1 or second cervical vertebra4 ,posteriorly there projects from the atlas two small lateral wings possessing articular facets which articulate with similar facets on the lateral wings of the axis4 ,posteriorly the body of the atlas is also provided with an articular surface which articulates with a similar surface on the anterior portion of the body of the axis4 ,the ,axis4 ,location4--,the axis is the second cervical vertebra4 ,it articulates anteriorly with the atlas1 and by a facet on the extreme anterior end of the odontoid process1 with the condyle of the occipital bone4 ,posteriorly it articulates with the third cervical vertebra4 ,description4--,the body of the axis is short4 ,the upper anterior portion of the body of the axis is provided with a tooth-like process called the odontoid process4 ,there are two anterior lateral wings provided with small articular facets which articulate with similar facets of the atlas4 ,the anterior surface of the body of the axis forms a true articulation with the body of the atlas4 ,the axis is provided with a superior and an inferior spine4 ,there are two posterior articular processes which articulate with the prezygapophyses1 or anterior articular processes1 of the third cervical vertebra4 ,the posterior part of the body of the axis forms a true articulation with the body of the third cervical vertebra4 ,other ,cervical ,vertebr4--,beginning with the axis1 the body of which is relatively short1 the body of each succeeding vertebra is longer than that of the preceding4 ,the articulations of each vertebra with adjoining vertebr are effected by means of diarthrodial facets1 convex in one direction and concave in the other4 ,illustration3 ,,fig4 #aj4--;,a4 ,diagram of three first dorsal vertebr and scapular arch-side view4 ,b4 ,diagram of section through the hemal arch4 ,a4 #a1 ,first dorsal segment4 #b1 ,second4 #c1 ,third4 #d and #e1 ,hemal arches4 #f1 ,the pleurapophyses or floating ribs4 #g1 ,the third pleurapophyses or dorsal vertebral rib articulating with the hemapophysis or sternal rib1 #h1 and this in turn with the wing of the sternum form a hemal arch4 #i1 ,the sternum4 #aj1 ,intervertebral foramen through which the nerves pass4 #aa1 ,articulation with the body of vertebra parapophyses4 #ab1 ,articulation with transverse process or diapophyses4 #ac1 ,oblique process or zygapophysis4 #ad1 ,the epipleural appendage4 ,b4 #a1 ,hemal or inferior spine 7hypapophysis74 #b1 ,the neural arch4 #c1 ,the pleurapophyses or rib4 #d1 ,the superior or neural spine or neurapophysis which aids in the formation of the anapophyseal ridge4 #e1 ,parapophyseal surface for head of rib4 #f1 ,tubercle of rib articulating with the diapophysis4 #g1 ,lamina of neurapophysis4 #h1 ,centrum4 #i1 ,hemal arch4 ,between the bodies of the vertebr are pads of fibrous cartilage4 ,above these bodies and inferior to the neural spines extends throughout the spinal column the large neural canal which is occupied by the spinal cord4 ,between the vertebral segments the neural canal is exposed superiorly1 since here the neural arches do not completely bridge the canal4 ,these spaces are protected by intervertebral ligaments4 ,in addition to the superior neural spines and the inferior spines1 from the body of the vertebra project lateral processes1 and anterior and posterior oblique processes4 ,all cervical vertebr except the atlas and the axis are made up of the following parts3 a body1 or centrum1 a neural canal1 a neural arch1 a superior dorsal1 or neural spine1 or neurapophysis1 which in most cervical vertebr is only slightly developed1 two oblique processes1 or zygapophyses1 two transverse processes1 or diapophyses 7,fig4 #aj1 ,no4 #ab7 and in some vertebr two tubercles1 or anapophyses above the posterior zygapophyses4 ,the prezygapophyses are directed upward and inward2 the postzygapophyses are directed downward and outward4 ,the inferior spines are only well developed in the last two or three cervical vertebr4 ,between vertebral segments1 except the central sacral portion1 on each side1 there is an intervertebral foramen 7,fig4 #aa1 ,no4 ,a1 #d71 through which pass the spinal nerves4 ,in the central portion of the sacrum where the vertebr have fused1 there are two foramina on each side for each original vertebra1 one located above the other1 the upper giving passage to the sensory branch1 the lower to the motor branch of the nerve4 ,the ,dorsal ,vertebr 7,fig4 #d1 ,no4 #bc2 ,fig4 #aa1 ,a74 ,location4--,the dorsal1 or thoracic vertebr1 or vertebr thoracicales1 aid in forming the roof of the chest cavity4 ,description4--,the dorsal vertebral section is made up of seven vertebr1 with strong short bodies4 ,the first and sixth dorsal segments articulate as do the cervical1 by the bodies and oblique processes4 7,fig4 #aa1 ,no4 ,a1 #c1 illustrates the oblique processes47 ,the seventh dorsal is fused with the first lumbo-sacral vertebra4 ,the second to the fifth inclusive of the vertebr are fused together1 and the superior and inferior spinous processes are fused into a prominent plate-like ridge4 ,the transverse processes of the dorsal vertebr1 from the second to the sixth1 are well developed and are bridged over with a thin layer of bone4 ,the ventral spines are partly fused and form a very prominent and continuous ridge4 7,fig4 #aa1 ,no4 ,a1 #a1 shows the fused superior spines2 ,no4 #b1 the fused inferior spines2 and ,no4 #d1 the intervertebral foramina47 ,the ,lumbo-sacral ,vertebr 7,fig4 #e1 ,part ,,ii1 ,no4 #d74 ,location4--,the fused lumbo-sacral section of the spinal column forms the roof of the pelvic cavity4 ,illustration3 ,,fig4 #aa4--;,bones from the scapular arch4 ,a4 ,dorsal vertebra4 #a1 ,superior spinous ridge1 #b1 ,inferior spinous ridge4 #c1 ,oblique processes4 #d1 ,intervertebral foramina4 #e1 ,articular facette for head of the rib4 #f1 ,articular facette for tubercle of the rib4 #g1 ,articular portion of the body4 ,b4 ,outer surface of scapula4 ,c4 ,inner surface of scapula4 #a1 ,thin caudal end4 #b1 ,articular head4 #d1 ,processus furcularis4 #e1 ,processus humeralis4 #f1 ,processus coracoideus4 ,d4 ,outer surface of coracoid4 ,e4 ,inner surface of coracoid4 #a1 ,the furcular tuberosity4 #b1 ,articular facette for articulation with the sternum4 #c1 ,articular surface for humerus and scapula4 ,f4 ,outer surface of humerus and ,g the inner surface of the same4 #a1 ,trochanteric fossa4 #b1 ,oval articular head at proximal end4 #c1 ,shaft4 #d1 ,distal end showing articular condyles4 #e1 ,trochanter4 #f1 ,trochlea for ulna4 #g1 ,trochlea for radius4 #h1 ,depression or fossa4 ,h4 ,section through the median plane of the humerus showing the delicate cross partitions illustrating provisions made for bones provided with air-sac extensions4 ,description4--,the lumbo-sacral region consists of fourteen vertebr which are distinct in the body of the newly hatched chick1 but which become fused soon after hatching4 ,with these vertebral segments there are fused the last dorsal and first coccygeal vertebral segments4 ,this fusion is so complete that the segments are indicated only by the intervertebral foramina on the sides through which the spinal nerves pass1 and by transverse markings on the inferior surface of the bodies4 ,the lumbo-sacral vertebr1 called the sacrum1 and the ilia are fused4 ,the dorsal spines of the vertebral segments are indicated only in the anterior portion where they are fused1 forming a plate4 ,there are no prominent ventral spines4 ,the ,coccygeal ,vertebr 7,fig4 #d1 ,no4 #bg74 ,location4--,the coccygeal or caudal vertebr1 or vertebr coccyge1 constitute the bones of the tail4 ,description4--,there are seven coccygeal vertebr4 ,the last segment1 shaped like a plough share and therefore called the pygostyle1 is the largest and is supposed to have been formed by the fusion of several original distinct segments4 ,it supports the coccygeal oil gland and the row of rudder feathers1 or rectrices1 which are arranged fan-wise4 ,all of the coccygeal vertebr except the first are freely movable1 thus allowing the tail to be used as a rudder during flight4 ,the lateral spines are long and well developed1 and the superior spines are bifurcated1 thus giving increased surface for muscular attachment4 ,the first coccygeal segment is fused with the last lumbo-sacral vertebra4 ,,the ,,thorax ,the dorsal vertebr superiorly1 the ribs laterally1 and the sternum1 or breast-bone inferiorly1 form the skeleton of a large cavity called the thorax4 ,the dorsal vertebr have been described4 ,the ,ribs 7,fig4 #d1 ,no4 #cb2 ,fig4 #aj1 ,a and ,b74 ,location4--,the ribs form the lateral bony wall of the thorax1 articulating superiorly with the dorsal vertebr4 ,description4--,the ribs are arranged in order of length1 the ultimate rib being the longest4 ,from anterior to posterior1 they approach more nearly a horizontal position4 ,the ribs are divided into the true and the false4 ,the true ribs articulate with the sternum4 ,the false ribs do not touch the sternum2 they are floating4 ,the true ribs are composed of two parts1 a vertebral1 or dorsal1 and a sternal1 or ventral4 ,the vertebral part1 or extremitas vertebralis1 is provided with an articular head1 or caput cost2 a neck1 or collum cost2 and an articular tubercle1 or tuberculum cost4 ,the head and tubercle articulate with the dorsal vertebra4 ,below the head of each rib is a pneumatic foramen4 ,the distal extremity of the dorsal section of the rib articulates with the proximal end of the sternal section by a diarthrodial articulation4 ,the articulations of the true ribs with the sternum is diarthrodial and each articulate by two small ridges with a double sternal facet4 ,the first1 the second1 and the seventh ribs are floating1 or false ribs4 ,the first rib articulates with the quadrate part of the last cervical vertebra and also with the first dorsal vertebra4 ,the seventh1 the last rib1 articulates with the under side of the anterior alar part of the ilium4 ,this rib is situated similarly to the true ribs2 but1 instead of articulating directly with the sternum1 the lower end lies against the sternal segment of the rib just anterior to it4 ,from the posterior edge of the second1 the third1 the fourth1 and the fifth ribs1 and near the middle of the dorsal segment1 are flat1 uncinate1 bony processes which project upward and backward1 overlying in each case1 the succeeding rib and giving greater surface for muscular attachments and greater stability to the thorax4 ,the ,sternum 7,fig4 #d1 ,no4 #dj2 ,fig4 #aj1 ,no4 ,a1 #i74 ,location4--,the sternum1 or breast-bone forms the inferior portion1 or floor of the thoracic cavity4 ,description4--,the sternum is a quadrilateral1 curved plate with processes projecting from each angle and from the middle of the anterior and posterior borders4 ,the posterior medial projection1 or metasternum1 is the longest1 and has a tall1 plate-like ridge--the sternal crest1 crista sterni--running along its ventral surface4 ,the crest serves the important function of increasing the bony area for the attachment of the powerful muscles which move the wings4 ,the anterior medial projection1 or rostrum1 is short1 and pierced at its root by an opening from which extend two elongated1 saddle-shaped depressions into which the end of the coracoid bones are received4 ,the plate-like process of bone1 the posterior lateral process1 which projects from the caudal angles of the sternum soon divides into two parts4 ,the shorter of these1 the oblique process1 broadens toward its free end and covers the sternal segments of the last two ribs4 ,the sides of the sternum are thus provided with an external and an internal process forming an external and an internal notch4 ,these notches are bridged over by a broad ligament1 to which the muscles are attached4 ,in poor flyers1 as the domestic fowl1 these notches are large4 ,the posterior end of the sternum is called the xiphoid process or processus xiphoideus4 ,anteriorly the sternum is provided with lateral external processes1 the costal processes4 ,the lateral borders of the sternum are pitted by four depressions into which the sternal segments of the ribs are received4 ,the dorsal1 or inner surface of the bone is pierced by openings by which the air-sacs communicate with the interior4 ,,the ,,appendicular ,,skeleton ,the appendicular skeleton consists of the shoulder girdle1 the fore limb1 the pelvic girdle1 or hip bone1 and the hind limb4 ,the shoulder girdle consists of the scapula1 the coracoid1 and the clavicle4 ,the fore limb consists of the arm1 forearm1 and the hand4 ,the arm consists of the humerus1 the forearm of the radius and the ulna2 and the hand consists of the carpus1 the metacarpus1 and the phalanges4 ,the pelvic girdle consists of the ilium1 the ischium1 and the pubis4 ,the hind limb consists of the thigh1 the leg1 and the foot4 ,the thigh consists of the femur1 and the leg consists of the tibia and the fibula4 ,the foot consists of the metatarsus and the phalanges4 ,,the ,,shoulder ,,girdle ,the shoulder girdle consists of the scapula1 the clavicle and the coracoid4 ,the ,scapula4 ,location4--,the scapula 7,fig4 #aa1 ,a1 ,b7 lies on the outer and superior rib surface1 extending parallel with the dorsal vertebr4 ,description4--,the scapula is a thin1 sword-like bone1 becoming thicker as it approaches the shoulder-joint4 ,the scapula expands and becomes thin near the free end1 which reaches nearly to the antero-lateral portion of the ilium 7,fig4 #d1 ,no4 #bd74 ,the scapula articulates with the coracoid4 ,a pneumatic foramen is located at the base of the acromion process4 ,the anterior part of the scapula is provided with an articular head and is provided with an inner process1 called the processus furcularis1 which lies near the furcula and coracoid4 ,an outer stronger processus humeralis forms the posterior half of the glenoid cavity1 or cavitas glenoidalis1 in which the humerus articulates and the processus coracoideus4 ,the ,clavicle4 ,location4--,the clavicles1 commonly known as the wish bone1 are located in the anterior chest region4 ,description4--,the clavicles are long1 slender bones uniting below in the hypocledium1 a laterally flattened process4 ,they are joined to the upper end of the coracoid by fibrous cartilage4 ,the hypocledium is joined to the anterior point of the sternum by the claviculosternal ligament4 ,the clavicles1 as united by the hypocledium1 form a v-shaped structure called the furculum1 or1 popularly1 the wish bone4 ,the forks play the part of an elastic spring1 whose office it is to prevent the wings from coming toward each other during contraction of the depressor muscles4 ,the conformation of this bone is1 therefore1 like the sternum1 related to the extent and power of flight2 and for this reason it is that1 in swift flyers1 the two branches of the furculum are thick1 solid1 widely separated1 and curved like a ,u2 while in those that fly heavily and with difficulty1 these branches are thin and weak1 and join at an acute angle4 ,the latter formation greatly diminishes its strength1 and lessens1 in a singular manner1 the reactionary power of the bony arch it represents4 ,the ,coracoid4 ,location4--,the coracoid is located just back of the clavicle and at the side of the entrance of the thoracic cavity4 ,it is the strongest bone of the shoulder girdle1 extending upward1 outward1 and forward4 ,it articulates inferiorly with the sternum and superiorly with the humerus and the scapula1 and is attached to the superior end of the furcular limb by a fibrous cartilage4 ,description4--,it is thinnest in the center or shaft and broadens toward the inferior extremity4 ,the upper hook-like part of the coracoid forms the fore part of the glenoid cavity1 and together with the scapula and furcula form the foramen triosseum through which passes the tendon of the elevator muscle of the wing4 ,the upper end flattens out into three tuberosities1 the tuberositas furcularis which is thick and to which attaches the limb of the furcula1 the tuberositas scapularis which unites to the scapula1 and the tuberositas humeralis which lies between these and articulates with the humerus4 ,,the ,,fore ,,limb ,the bones of the fore limb are humerus1 ulna1 radius1 carpus1 metacarpus1 and phalanges4 ,the ,humerus4 ,location4--,the humerus constitutes the arm1 which1 when at rest1 lies parallel to the dorsal vertebr4 ,it articulates superiorly with the glenoid cavity1 a shallow ball-and-socket joint1 formed by the scapula and the coracoid2 and inferiorly with the ulna and radius4 ,description4--,the proximal extremity of the humerus is provided with a trochanter 7,fig4 #aa1 ,g1 ,no4 #e7 and a large oval head or caput humeri1 which articulates in the glenoid cavity4 ,the head is an elongate1 semi-oval convexity1 with the long axis transverse from the radial to the ulnar side and with the ends continued into upper and lower crests4 ,the upper crest of the head of the humerus is on the radial side and the lower crest on the under side4 ,under this latter crest there is a pneumatic fossa 7,fig4 #aa1 ,f1 ,no4 #a71 at the upper end of which there is an opening into the bone1 the pneumatic foramen1 which brings the air-sac into communication with the air space of the bone4 ,the shaft1 or corpus humeris1 is irregularly cylindrical and slightly ,s-shaped4 ,the proximal part of the shaft1 which is expanded on the palmar side1 is concave across and convex lengthwise4 ,the distal part is slightly flattened4 ,the shaft of the humerus is almost cylindrical4 ,the distal extremity of the humerus is provided with two articular condyles1 one of which articulates with the ulna and the other with the radius4 ,on the radial side of the palmar surface there is a ridge2 and on the ulnar side of the same surface there is a second ridge diverging to the opposite tuberosity4 ,the radial surface is a narrow1 subelongate convexity1 extending from the middle1 approximately1 of the palmar surface1 obliquely to the lower part of the radial tuberosity4 ,the two articular convexities1 or trochlea1 at the distal end of the humerus are bent toward the palmar aspect1 the anconal aspect is the side on which the elbow is situated4 ,the inner convexity is the larger and articulates with the ulna4 ,to the outside is the processus cubitalis humeri4 ,the outer articulates with the radius and is so arranged that the radius makes a greater flexion than the ulna4 ,at the lower end of the humerus there is a depression which receives the anconeus of the ulna during flexion and extension of the forearm4 ,on the shoulder- and elbow-joint are found grooves over which the tendons glide1 at which places sheaths are provided4 ,this arrangement also aids in keeping the capsular ligament in place4 ,the ,ulna4 ,location4--,the ulna1 larger than the radius1 is bent and articulates with the radius only at the ends4 ,the two bones are bound together by a ligamentous band4 ,it also articulates superiorly with the distal end of the humerus1 and inferiorly with the carpus4 ,when the wing is folded the radius is superior and a trifle to the inner side of the ulna4 ,description4--,the proximal end is most expanded1 and is obliquely truncate for the articular excavation adapted to the ulnar tubercle of the humerus4 ,a short angular process behind the cavity represents the olecranon1 which is the processus olecranalis coracoideus uln to which the ligamentum capsulare cubiti attaches4 ,on the inner side of the head is the internal tubercle of the ulna and on the external side the external tubercle of the ulna4 ,an excavation is noted on the radial side of the proximal end for the lateral articulation of the head of the radius4 ,on the upper side near the articular part is located the sigmoid cavity4 ,the shaft1 or corpus uln1 decreases in size near the distal end4 ,it is slightly curved1 flattened laterally with an internal and an external ridge4 ,the distal end of the ulna is slightly expanded into a trochlea which is sharply convex and articulates with two free carpal bones1 the scapho-lunar1 or os carpi radiale1 and the cuneiform1 or os carpi ulnare4 ,the scapho-lunar is placed on the radial side1 and the carpiulnare on the ulnar side4 ,the distal extremity of the ulna is provided with a styloid process and on the dorsal side with a tubercle4 ,the ,radius4 ,location4--,the radius lies beside the ulna with which it articulates at each extremity4 ,at the inferior extremity the articulation is rotary4 ,it also articulates superiorly with the humerus and inferiorly with the os carpi radiale4 ,description4--,the radius1 cylindrical in shape1 is more slender than the ulna4 ,the proximal end is expanded1 subelliptical1 with a concavity for the oblique tubercle and a thickened convex border for articulation with the ulna4 ,this end is provided with the tuberositas radii4 ,the shaft1 or corpus radii1 is slender1 subcompressed1 and has a slight bend upward from the ulna4 ,a nutrient foramen occurs in this shaft4 ,the distal end is expanded and rather flattened with two grooves on the anconal side for passage of tendons4 ,for articulation with the scapho-lunar the radius is provided with a terminal transverse convexity produced palmad1 which also articulates with the ulna laterally4 ,there is a tuberosity on the radial side of the expansion and inferiorly the inferior tuberculum ossis carpi radialis and superiorly a superior tuberculum ossis carpi radialis4 ,the ,hand4--,the hand is made up of the carpus1 the metacarpus1 and the phalanges4 ,the bones of the hand are so arranged as to allow abduction and adduction1 or flexion in the ulno-radial plane1 movements which are necessary in the outspreading and folding of the wing4 ,thus the hand of the fowl moves in a state of pronation1 without the power of rotation4 ,the carpal bones are so placed between the anterior arm and metacarpus as to reduce the abduction which is necessary to hold and extend the wing1 so that the hand or wing be in a fixed position4 ,the ,carpus4--,the carpus in the domestic fowl is represented by two bones1 ossa carpi1 called the scapho-lunar1 or os carpi radiale1 and the cuneiform1 or os carpi ulnare4 ,the scapho-lunar is the smaller and is located between the radius and metacarpus4 ,the cuneiform is the larger and is located between the ulna1 the radius1 and the metacarpus4 ,the cuneiform is somewhat anvil-like in shape1 being provided with a body and two prongs4 ,the ,metacarpus4--,the metacarpal bones1 or ossa metacarpi1 two in number1 are separated at their middle portion1 and consolidated at their extremities4 ,the upper proximal base of the metacarpus is provided with a tubercle1 the tuberculum muscularis1 and externally the tuberculum ulnare ossis metacarpi4 ,the distal end of the metacarpal bone is provided with a tuberculum articulare4 ,the ,phalanges4--,the first three fingers only are represented1 and these are rudimentary4 ,the first finger called the pollex or thumb1 consists of but one joint4 ,it is located on the proximal and outer end of the metacarpal bone4 ,it has on its proximal end a tubercle1 the tuberculum articulare4 ,the second finger1 the best developed1 consists of two phalanxes4 ,these are the main bones extending from the metacarpus4 ,each articular end is provided with a tuberculum articulare4 ,the third finger1 small1 cylindrical in shape1 is located at the distal and inner side of the metacarpal bone4 ,,the ,,pelvic ,,girdle 7,fig4 #d1 ,no4 #be2 ,fig4 #e1 ,part ,,ii1 #f7 ,the pelvic girdle is made up of three bones as follows3 the ilium1 the ischium1 and the pubis1 all of which are fused in adult life4 ,they are separate in the baby chick 7,fig4 #e1 ,part ,,ii1 #f74 ,the pelvis together with the lumbo-sacral vertebr forms a thin1 irregular1 shell-like structure extending superiorly from the tail to the thoracic region4 ,the sacrum is broad posteriorly and together with the ilium forms the pelvic roof4 ,the ilium and ischium are its lateral walls4 ,the top surface of the pelvis shows the fovea ilio-lumbalis dorsalis1 which is bounded mesially by the crista ilii4 ,between it and the spina lumbalis there is a broad furrow1 the bottom of which is formed by the dorsal surface of the lumbar vertebr4 ,the sulcus ilio-lumbalis dorsalis is formed by the rims of the ilia1 so that a ridge is observable4 ,the cavum ilio-lumbale dorsale is formed by the iliac rims on either side4 ,anteriorly is the canalis ilio-lumbalis1 which is formed by the ilium and the lumbar vertebral spines4 ,it is located longitudinally to the vertebr4 ,the anterior opening of this canal is the larger4 ,posterior to the acetabulum is the post-acetabular ridge4 ,the under part of the pelvis presents three distinct regions4 ,the cavity is divided into the fovea lumbalis1 or anterior part1 the fovea ischiadica1 or mesial part1 and the fovea pudendalis1 or posterior part4 ,posterior to these is the region called the planum coccygeum4 ,the fovea lumbalis contains the anterior lobe of the kidney1 and is circumscribed anteriorly by the last rib-carrying vertebra1 and posteriorly by the transverse process of the last lumbar vertebra4 ,in the fovea ischiadica which follows1 lie the nerve plexus ischiadicus and the middle lobe of the kidney4 ,its posterior boundary is the linea arcuata4 ,the linea arcuata is a line drawn from the acetabulum of the one side to the acetabulum of the other side4 ,the fovea pudendalis contains the posterior lobe of the kidney4 ,the posterior boundary is the anterior border of the first coccygeal vertebra4 ,it gives passage to the nerve plexus pudendo-hemorrhoidalis4 ,the ilium1 the ischium1 and the pubis join to form the cotyloid cavity1 or acetabulum1 in which articulates the head of the femur4 ,the floor of the cavity is perforated by a relatively large round foramen4 ,the ,ilium4 ,location4--,the ilium1 together with the lumbo-sacral vertebr1 forms the roof of the pelvic cavity4 ,it articulates at its inner border with the lumbo-sacral vertebr1 postero-laterally with the ischium and at the cotyloid cavity with the pubis4 ,description4--,the ilium is remarkable for its development in the long axis of the vertebral column4 ,it is long and narrow2 and mesially1 where it is thickest it forms the upper wall of the acetabulum4 ,anterior to the acetabulum it is outwardly concave1 and posterior to the acetabulum it is convex4 ,the ilium fuses with the last dorsal vertebra and with the lumbo-sacral vertebr and is excavated on its internal face4 ,this surface is irregular and lodges the kidneys4 ,this inner margin of the renal part enters with the square extensions of the posterior excavation passing into the posterior iliac spine4 ,the external margin is the extension of the crista transversa and forms the processus ischiadicus4 ,posteriorward the renal part of the ilium joins the ischium4 ,the ilia converge at the summits of the anterior sacral spines forming the ilio-lumbar spines4 ,the ilium is joined to the square extensions of the last sacral vertebra by the symphysis ilio-sacralis1 to the larger part of the lumbar vertebr by the sutura ilio-lumbalis1 and to the transverse processes of the last sacral vertebr by the symphysis ilio-sacri4 ,the ,ischium4 ,location4--,the ischium is located in the postero-inferior part of the pelvis4 ,it joins superiorly with the ilium1 and inferiorly with the pubis4 ,description4--,the ischium is smaller than the ilium and is a flattened1 triangular-shaped bone1 thickest where it forms the posterior part of the acetabulum1 becoming thinner and broader as it extends backward4 ,posteriorly it forms the caudal extension4 ,the inferior border is turned slightly outward and is fused with the pubis4 ,between these bones there is located the large oval ischiadic foramen1 through which passes the ischiadic nerve4 ,this bone aids the ilium in the formation of the obturator foramen through which passes the tendon of the internal obturator muscle4 ,the lower part of the ischium which separates the ischiadic foramen from the obturator foramen is called the ramus ascendens ossis ischii4 ,the ,pubis4 ,location4--,the pubis is located along the inferior margin of the ischium and extends further back than the posterior border of the ischium4 ,description4--,the pubis is a long1 slender1 rib-like bone4 ,it forms the lower and front portion of the acetabulum4 ,the ischiadic foramen formed by the ischium and pubis is single and nearly circular in fowls1 double in pigeons1 and in geese and ducks it is elongate4 ,,the ,,hind ,,limb 7,fig4 #d1 ,nos4 #ce1 #dg1 #dh1 #di1 #ej1 #ea1 #eb1 and #ec2 ,fig4 #ab7 ,the pelvic1 or hind1 limb supports the body4 ,the bones of each leg are the femur1 which constitutes the thigh1 the tibia and the fibula1 which represents the leg1 and the metatarsus and the phalanges1 which form the foot4 ,the ,femur 7,fig4 #ab1 ,a and ,b74 ,location4--,the femur1 or os femoris1 the first bone of the hind extremity1 extends obliquely downward and forward1 articulating with the acetabulum above and the tibia1 the fibula1 and the patella below4 ,description4--,the femur1 one of the largest1 thickest1 and strongest bones of the body1 belongs to the class of cylindrical bones1 and presents for examination a shaft and two extremities4 ,the superior1 or proximal extremity1 is provided with a head1 caput femoris2 the neck1 collum femoris2 and the trochanter4 ,the head is relatively small1 and is marked by a depression above for the round ligament which fills the cavity in the acetabular wall4 ,its axis is nearly at right angles with the shaft4 ,a neck joins it to the body at the proximal end4 ,external to the head of the femur is the trochanter4 ,the trochanter presents an outer convexity over which the tendon of the gluteus maximus extends to become inserted below4 ,the trochanteric ridge1 which is opposite the articular head1 presents an outer flattened surface which possesses impressions for muscular attachments4 ,the trochanteric fossa1 or fossa trochanterica1 is shallow4 ,the shaft1 or corpus femoris1 is shorter than the tibia1 is in general cylindrical1 bent forward1 and the lower half is flattened and expanded transversely4 ,a nutrient foramen is located in the median portion of the shaft4 ,the shaft shows muscular linear ridges4 ,the distal extremity is large in both directions and comprises the trochlea in front and two condyles behind1 one internal and one external4 ,the condyles are separated by the intercondyloid fossa1 or fossa intercondyloidea1 which is marked with pits for the attachment of ligaments2 and above this is the epitrochlear fossa4 ,illustration3 ,,fig4 #ab4--;,bones of the hind extremity4 ,a4 ,posterior view of femur4 ,b4 ,anterior view4 #a1 ,shaft4 #b1 ,proximal extremity4 #c1 ,distal extremity4 #d1 ,articular head4 #e1 ,trochanter major4 #f1 ,shallow trochanteric fossa4 #g1 ,convexity over which the tendon of the gluteus maximus glides4 #h1 ,external condyle4 #i1 ,internal condyle4 #aj1 ,nutrient foramen4 #aa1 ,intercondyloid fossa4 #ab1 ,muscular linear ridges4 #ac1 ,epitrochlear fossa4 ,c4 ,internal view of tibia4 ,d4 ,external view4 #a1 ,shaft4 #b1 ,articular head4 #c1 ,distal end4 #d1 ,the rotular process4 #e1 ,the fibular ridge4 #f1 ,external condyle4 #g1 ,internal condyle4 #h1 ,intercondyloid space4 #i1 ,nutrient foramen4 ,e4 ,fibula1 lateral view4 #a1 ,articular head4 #b1 ,its attenuated portion4 ,f4 ,posterior view of metatarsus4 #a1 ,trochlea for inner or second digit4 #b1 ,trochlea for middle or third toe4 #c1 ,trochlea for outer digit4 #d1 ,bony core for spur4 #e1 ,bony canal for tendons4 #f1 ,groove for tendons4 #g1 ,fossa intercondyloidea4 ,the inner condyle begins anteriorly as a ridge1 and expands into a convexity which attains its greatest breadth posteriorly where it becomes more flattened4 ,the inner side of the inner condyle is flattened and is provided with a tuberosity at its mid-part and a second just above the posterior part of the condyle4 ,the outer condyle is formed in the same manner as the inner condyle4 ,it is indented at its broad1 lower end by an angular groove1 which1 winding divides the posterior part of the condyle into two convexities4 ,the more external convex ridge and the groove dividing it from the outer condyle are adapted to the head of the fibula4 ,there is in this part a fibular ridge and above this ridge a tuberosity4 ,the ,tibia4 ,location4--,the tibia 7,fig4 #ab1 ,d and ,c7 extends obliquely downward and backward from the knee-joint to the hock4 ,it articulates above with the femur and1 by its procnemial process with the patella1 below with the metatarsus1 and laterally with the fibula4 ,description4--,the tibia is the longest bone in the posterior limb1 and possesses a shaft and two extremities4 ,it is largest at the proximal end and presents three faces4 ,the proximal extremity presents a semi-oval articular surface1 not quite at right angles with the shaft1 which articulates with the condyles of the femur4 ,the margin is raised toward the anterior of the bone4 ,the head of the tibia1 or caput tibi1 extends into a rotular process which extends transversely1 and is truncate4 ,from the anterior of this process there descends two vertical ridges2 one near the angle of the rotular process1 the procnemial ridge2 the other from the outer fibular angle1 the ectocnemial ridge4 ,on the outer side of the intercondylar tuberosity there is a surface for the ligamentous union with the head of the fibula2 and a short distance below this there is a vertical ridge for the close attachment1 almost a fusion1 with the fibula1 called the fibular ridge4 ,the shaft1 or corpus tibi is straight and the upper two-thirds subtrihedral2 the lower third oval4 ,a nutrient foramen occurs near the upper postero-internal portion of the middle third of the bone4 ,the distal extremity is much smaller than the proximal one2 it is quadrangular in form4 ,the expanded inferior end of the tibia forms two articular condyles above which posteriorly there is the epicondyloid fossa4 ,the inner condyle1 the larger1 has a groove near the lower end of the anterior part of the shaft1 which deepens toward the intercondyloid space4 ,this intercondyloid fossa in young birds is covered by a strong ligament1 which in older birds1 becomes ossified4 ,on the lateral side of each condyle1 there is a depression for the attachment of ligaments4 ,the ,patella4 ,location4--,the patella1 or knee-cap1 thin and wide1 articulates with the procnemial process of the tibia1 and with the deep trochlea of the distal end of the femur4 ,description4--,the patella is irregular in shape with three faces and three borders4 ,the posterior surface is articular4 ,the other two surfaces are rough for tendinous attachment4 ,the patellar ligaments in old birds may become ossified4 ,in order to turn the foot in and out1 the tibia not only turns around the inner condyle of the femur1 but also around the patella1 so that the posterior surface turns outward and thus turns outward the metatarsus and all the toes4 ,the ,fibula4 ,location4--,the fibula lies at the outer border of the tibia4 ,it articulates superiorly with the outer condyle of the femur1 and laterally with the tibia4 ,description4--,the fibula is rudimentary2 it is largest superiorly and tapers to a slender point4 ,the head is compressed laterally1 and furnishes an upper and an inner articular surface4 ,the ,tarsus4--,there exist1 during fetal development of the chick1 two rows of tarsal bones which later become fused4 ,the upper row fuses with the tibia and the lower with the metatarsus4 ,therefore1 in the adult1 there is no tarsus4 ,the ,metatarsus4 ,location4--,the metatarsal bone extends downward and forward4 ,in birds it consists of one bone1 which articulates superiorly with the inferior extremity of the tibia4 ,on the distal end it has a threefold trochlear arrangement which articulates with the three principal digits4 ,description4--,the proximal extremity posteriorly has a process which may be considered as a consolidation of originally separate metatarsal bones4 ,the process at the supero-posterior part of the metatarsus is called the hypotarsus of the tarso-metatarsus1 through which extends a canal called the hypotarsal canal1 and which gives passage to flexor tendons4 ,the proximal end of the metatarsus is ossified from one center of ossification forming an epiphysis which caps the ends of the three original metatarsal bones that coalesce1 first with one another1 then with the epiphysis1 thus forming a single compound bone4 ,above and just to the inside of the metatarsus there may occur a small bone which is imbedded in ligaments and articulates with the inner proximal surface of the metatarsus4 ,this has been called by ,gadow a sesamoid bone4 ,the shaft shows tendonal grooves which are best marked on the posterior surface4 ,the shaft is rounded at the sides and flattened on the anterior and posterior surfaces4 ,at the juncture of the middle and inferior thirds of the metatarsus there is a conical process turned slightly backward1 which serves as a base for the spur4 ,the spur is a horny structure4 ,at the distal extremity occurs the threefold trochlear arrangement mentioned above1 which incloses the fossa intercondyloidea4 ,the inner trochlea is the broadest1 and the outer the narrowest4 ,the inner trochlea articulates with the proximal end of the second1 the middle with the third1 and the outer with the fourth toe4 ,the ,phalanges4 ,location4--,most domestic fowls are provided with four digits1 or toes2 the ,houdan and ,dorking are provided with five4 ,in fowls with four toes the three principal toes1 the second1 the third1 and the fourth1 are directed forward1 and the first1 or hallux1 is directed backward4 ,description4--,the last phalanx of each toe1 called the ungual phalanx1 is slightly curved downward1 is pointed anteriorly1 like the claw of the cat or dog1 and is covered with a horny sheath4 ,the articular ends of the joints of the phalanges are enlarged4 ,the base of the basal phalanx has two enlargements1 the superior-inferior tubercles1 or tuberculum superius et inferius1 between which is located the fossa articularis transversa4 ,laterally the head has two condyles1 condyli laterales1 which are divided by the sulcus longitudinalis4 ,the bodies of the phalanges vary in form2 they are superiorly rounded1 but inferiorly rounded1 flat1 or even somewhat concave4 ,the distal extremity has an articular trochlea4 ,the first toe1 or digit1 called the great toe1 or hallux1 is composed of three phalanges1 or segments4 ,the first segment1 or basal phalanx is considered a rudimentary metacarpal bone2 it is attached by a fibrous cartilaginous tissue to the inner posterior surface of the inferior extremity of the metacarpal bone just below the spur4 ,the second toe1 likewise composed of three phalanges1 is directed forward4 ,it articulates with the inner trochlea located on the inferior metacarpal bone4 ,the third toe1 made up of four phalanges1 is the middle of the three forward toes4 ,it articulates with the middle trochlea of the inferior extremity of the metacarpal bone4 ,the fourth toe1 is composed of five phalanges2 it is1 however1 of approximately the same length as the third1 the segments being shorter4 ,the fourth or outer toe articulates with the outer trochlea of the distal extremity of the metacarpal bone4 ,,arthrology ,kinds of ,joints4--,joints may be movable1 immovable1 or mixed4 ,in movable1 or true joints the articular surface of each bone is covered by cartilage4 ,the bones are held together by ligaments1 the capsular one often surrounding the joint and enclosing the synovial membrane4 ,in some joints there is a pad of fibrous cartilage interposed between the two articular cartilages4 ,such a pad1 called a meniscus1 adds to the elasticity and the free movement of the joint4 ,movable joints form the most numerous class2 they are for the most part found in the limbs4 ,in an immovable joint there is only a thin layer of fibrous or cartilaginous material interposed between the bones4 ,the fibrous layer of the periosteum of both bones unite to cover the connecting material and becomes attached to the same1 thus serving as a ligament4 ,if the connecting material is fibrous1 the joint is called a suture2 if cartilaginous1 a synchondrosis4 ,these joints are found in the skull and in the pelvis4 ,the term mixed is used with reference1 not to the motion in joints1 but to their structure1 which partakes of the nature of both the movable and immovable4 ,the bones are firmly joined by a strong interposed pad of fibrous cartilage to which also is adherent the ligaments of the joint4 ,there are no capsular ligaments2 the cartilaginous pad or disc is softer toward its center1 where occasionally there may be one1 or even two1 narrow cavities4 ,authorities differ as to whether such cavities are lined by synovial membrane or not4 ,since there are really no frictional surfaces in such a joint1 motion depends upon the flexibility of the disc4 ,the joints between the vertebral centra afford the best illustration of the mixed class4 ,movement of ,joints4--,the movements admissible in joints may be divided into four kinds3 gliding1 angular movement1 circumduction1 and rotation4 ,these movements are often1 however1 more or less combined in the various joints4 ,it is seldom that there occurs only one kind of motion in any particular joint4 ,gliding movement is the most simple kind of motion that can take place in a joint1 one surface gliding or moving over another without any angular or rotary movement4 ,angular movement occurs only between the long bones4 ,by it the angle between the two bones is increased or diminished4 ,it may take place in four directions3 forward and backward1 consisting of flexion and extension2 or inward and outward from the medial line of the body1 consisting of adduction and abduction4 ,abduction of a limb is movement away from the medial line of the body4 ,adduction of a limb is movement toward the medial line of the body4 ,circumduction is that limited degree of motion which takes place between the head of a bone and its articular cavity1 whilst the extremity and sides of the limb are made to circumscribe a conical space1 the base of which corresponds with the inferior extremity of the limb1 the apex with the articular cavity2 this kind of motion is best seen in the shoulder- and hip-joint4 ,rotation is the movement of a bone upon an axis1 which is the axis of the pivot on which the bone turns1 as in the articulation between the atlas and axis1 when the odontoid process serves as a pivot around which the atlas turns2 or else is the axis of a pivotlike process which turns within a ring1 as in the rotation of the radius upon the humerus4 ,pronation is a form of rotation in which the inferior extremity of the radius passes before the ulna1 and thus causes the hand to execute a kind of rotation from without inward4 ,supination is a form of rotation in which the movement of the forearm and hand are carried outward so that the anterior surface of the latter becomes superior4 ,the ,ligamentous ,structure4--,ligaments are dense1 fibrous1 connecting structures4 ,they are made up principally of white fibrous tissue and exist in all true joints4 ,there are four kinds of ligaments associated with true joints3 ,the first kind1 the capsular ligament which encloses all true joints1 is thin and consists of interlaced fibers attached to the bone at the edges of the articular cartilages4 ,it either partly or wholly surrounds the joint1 enclosing and protecting a synovial apparatus1 which1 by secreting a liquid resembling serum1 lubricates the joint to prevent friction4 ,the second kind1 the binding or lateral ligaments1 consist of flattened or rounded cords or bands of fibrous tissue4 ,such a ligament extends from one bone to the other1 and firmly attached to their roughened surfaces1 holds the bones in place and at the same time allows the required amount of motion4 ,the third kind1 located between the joints1 is called interosseous ligament4 ,the fourth kind1 called the annular ligament binds down and protects the tendons4 ,ligaments of the ,ear#b4--,the concha of the ear is provided with a superior and an inferior ligament4 ,footnote #b3 ,the classification of ,gadow is used4 ,ligaments of the ,jaw4--,the articulations of the lower jaw are complex4 ,the freely movable articulation is between the inferior maxilla and the quadrate4 ,less freely movable articulations are formed by the quadrate with the temporal1 the zygomatic and the pterygoid4 ,a lateral ligament of the jaw1 the articulo-jugale extends from the posterior border of the inner wing of the os articulare of the inferior maxilla 7,fig4 #h1 ,no4 #aj1 and ,fig4 #ai1 ,no4 #ae7 to the outer border of the os quadrato jugulare4 ,a lateral temporo-maxillary ligament extends from the outer surface of the temporal bone to the outer border of the os articulare of the inferior maxilla 7,fig4 #h1 ,no4 #aa1 and ,fig4 #ai1 ,no4 #ad74 ,ligaments of the ,vertebr4--,in each space between the bodies of the vertebr there is a meniscus intervertebralis4 ,this meniscus is analogous to the annulus fibrosus of mammals 7,gadow71 which1 is possibly formed as a protrusion of the anterior surface of the vertebral body4 ,the meniscus or disc may develop into a ring-shaped structure1 the true meniscus1 or it may develop to different degrees as an extension of the vertebral body surface1 and become1 as in the dorsal and lumbar regions1 fused with the vertebral segments1 in which case it is called the annulus fibrosus4 ,the vertebral disc which is connected with the atlas and which is fused with that bone1 represents the first meniscus1 which is called the ligamentum transversum atlantis4 ,this1 as well as other ligaments of the spinal column1 may become ossified4 ,the ligament which is located between those vertebral bodies which face each other and is inside the joint cavity1 is called the ligamentum suspensorium corporum vertebralium4 ,it passes through the central opening of the meniscus and lies exactly in the long axis of the body of the vertebra4 ,the first ligament of the neck is the ligamentum suspensorium dentis epistrophei4 ,the ligamentum capsulare atlantico-occipitale and the ligamentum capsulare atlantico-epistrophicum odontoideum are two parts of the joint capsule of the vertebral body4 ,other ligaments of this part are the membran obturatori intervertebrales posteriores1 which are located between the semicircular rims of the neck vertebr4 ,the ligamentum transversum atlantis surrounds the occipital condyle4 ,the ligamentum nuch is a thin1 membranous1 ribbon-like structure which lies between the muscles of the right and those of the left side of the middle1 and the lower part on the posterior of the neck1 and ends in attachments to the superior spines of the cervical vertebr4 ,the ligamentum elasticum interspinale profundum and the ligamentum elasticum interspinale superficiale and the three last named are the ligaments which keep the neck of the fowl in the s-shape1 without the action of the muscles4 ,the ligamentum capsulare obliquum connects the facets of the oblique processes4 ,ligaments of the ,ribs4--,the thick inferior end of the sternal portion of the true rib has two small articular heads1 which articulate with two depressions in the articular surface of the sternum4 ,this articulation is held firm by a capsular ligament4 ,the upper end of the sternal rib forms an almost perfect right angle with the inferior end of the dorsal rib with which it is connected by a joint provided with a synovial apparatus and a capsular ligament4 ,this arrangement allows free movement outward and inward and is the main joint in respiration4 ,the upper end of the dorsal portion of the rib articulates with the dorsal vertebra4 ,the joint formed by the articular head with the body of the vertebra is provided with a capsular ligament4 ,the tubercle of the rib articulates with the facet on the transverse process of the dorsal vertebra1 and is provided with a transverse ligament1 called the ligamentum transversum externum4 ,it is also provided with a capsular ligament4 ,the ligamentum triangulare connects each processus uncinatus with the succeeding rib4 ,this ligament is in the form of a membranous sheet1 or aponeurosis4 ,ligaments of the ,sternum 7,fig4 #ac74--,the external and the internal notches of the sternum are bridged over with a thin membrane which gives an extensive surface for muscular attachments4 ,the sternal muscles overlie this portion4 ,illustration3 ,,fig4 #ac4--,muscles of the fore extremity4 ,inside view4 #a1 ,lateral external process of sternum4 #b1 ,lateral internal process of same4 #c1 ,ligament of the external notch4 #d1 ,ligament of the internal notch4 #e1 ,pectoralis major4 #e;a1 ,its fan-shaped expansion at shoulder-joint laid back4 #f1 ,pectoralis tertius4 #g1 ,the coracoid4 #h1 ,biceps4 #h;a1 ,its long head4 #h;b1 ,its short head4 #i1 ,pectoralis secundus4 #aj1 ,rectus abdominis4 #aa1 ,teres et infraspinatus4 #ab1 ,deltoid4 #ac1 ,capsular ligament4 #ad1 ,teres minor4 #ae1 ,coraco-brachialis4 #af1 ,serratus magnus anticus4 #ag1 ,extensor metacarpi radialis longior4 #ah1 ,pronator brevis4 #ai1 ,flexor carpi ulnaris4 #bj1 ,flexor carpi ulnaris brevior4 #ba1 ,flexor digitorum profundus4 #bb1 ,extensor indicis longus4 #bc1 ,extensor ossis metacarpi pollicis4 #bd1 ,humerus4 #be1 ,shoulder4 #bf1 ,elbow4 #bg1 ,carpus4 #bh1 ,section through vertebra4 #bi1 ,keel of sternum4 #bh;a1 ,flexor brevis pollicis4 #bi;a1 ,extensor proprius pollicis4 #cj1 ,flexor minimi digiti brevis4 #ca1 ,interosseous palmaris4 #cb1 ,interosseous palmaris4 ,the sternum is connected by a fibrous mass with the inferior portion of the clavicle1 or hypocledium 7,fig4 #eg71 the claviculosternal ligament4 ,the inferior narrow elongated end of the coracoid forms with the sternum a true articulation1 which is provided with a capsular ligament1 the ligamentum capsulare4 ,capsular ligaments occur at the articulations between the sternum and ribs4 ,ligaments of the ,shoulder-joint 7,fig4 #ac74--,the shoulder-joint is made up of the scapula1 the humerus1 and the coracoid4 ,the ends of these three bones form the foramen triosseum 7,fig4 #ae1 ,no4 ,a1 #g7 through which passes the tendon of the elevator muscle of the wing4 ,the furcula1 independent of the shoulder-joint or girdle1 is attached to the supero-internal part of the proximal end of the coracoid by fibrous connective tissue2 it is also connected to the other bones of the shoulder-joint by the ligamentum coraco-furculare and the ligamentum furculo-scapulare4 ,the ligamentum coraco-scapulare extends from the tuberosity of the furcula to the coracoid and to the processus furcularis of the scapula4 ,the ligamentum coracoido-scapulare externum extends between the external tuberosity of the coracoid1 the tuberosity of the scapula1 and the humerus4 ,the ligamentum coracoideo-scapulare inferius extends from the coracoid to the inner tubercle of the scapula4 ,another long1 broad ligament belongs to the episternal apparatus4 ,the shoulder-joint is provided with a wide1 loose1 capsular ligament 7,fig4 #ac1 ,no4 #ac74 ,attached to the humerus are four other ligaments1 of which three pass from the anterior end of the coracoid and the fourth from the scapula4 ,the latter are as follows3 first1 the supero-anterior ligamentum humero-coracoideum1 which extends from the small tubercle of the humerus to the coracoid bone2 second1 the antero-inferior ligamentum humero-coracoideum1 which extends from the humerus to the coracoid2 third1 the ligamentum coraco-humerale1 which extends from the coracoid to the large tubercle of the humerus2 fourth1 the ligamentum humero-scapulare which extends between the processus humeralis of the scapula and the head of the humerus4 ,ligaments of the ,elbow-joint 7,fig4 #ad74--,the elbow-joint is made up of the ulna1 radius and the humerus4 ,the ligaments of the elbow-joint are as follows3 the ligamentum capsulare cubiti1 or capsular ligament1 which extends from the processus cubitalis of the humerus to the processus olecranalis coracoideus of the ulna and to the tuberositas radii of the radius 7,fig4 #ae1 ,no #e74 ,the ligamentum laterale cubiti externum connects the outer humeral distal extremity with the head of the radius 7,fig4 #ae1 ,no4 #b74 ,the ligamentum laterale cubiti internum lies between the inner distal extremity of the humerus and the tuberculum internum of the ulna 7,fig4 #ad1 ,no4 #i74 ,the ligamentum annulare radii originates on the olecranon1 surrounds the head of the radius1 and is attached to the tuberculum internum of the ulna 7,fig4 #ae1 ,no4 #c74 ,the ligamentum cubiti teres extends from the head of the radius to the upper end of the ulna 7,fig4 #ae1 ,no4 #d74 ,illustration3 ,,fig4 #ad4--,muscles and ligaments of the arm and forearm of a hen4 ,a4 ,external view4 #a1 ,expansor secundarium4 #b1 ,tensor patagii longus4 #c1 ,tensor patagii brevis4 #e1 ,brachialis anticus4 #f1 ,pronator longus4 #g1 ,supinator brevis4 #h1 ,extensor indicis brevis4 #aj1 ,scapulo-humeralis4 ,b4 ,internal view4 #i1 ,ligamentum laterale cubiti internum4 ,the ligamentum transversum spreads out between the head of the ulna and the radius1 thus uniting the two bones1 and limiting supination 7,fig4 #ae1 ,no4 #a74 ,ligaments of the ,carpal ,joint4--,the carpal joint is made up of the ulna1 radius1 the two carpal bones and the metacarpus4 ,there are two strong ligamenta obliqua carpi ulnaris which extend from the processus styloideus of the ulna to the tuberculum posterius carpi ulnaris of the os carpi ulnaris4 ,the ligamentum posticum ulnare carpi ulnaris extends from the processus styloideus of the ulna to the os carpi ulnaris4 ,illustration3 ,,fig4 #ae4--,ligaments of the arm and forearm of a hen4 ,a4 ,the scapulo-coraco-humeral articulation4 #a1 ,proximal end of the humerus4 #b1 ,articular head of humerus4 #c1 ,the coracoid4 #d1 ,proximal end of the clavicle4 #e1 ,tendon of pectoralis tertius4 #f1 ,tendon of pectoralis secundus4 #g1 ,opening or foramen triossium through which the tendon of the elevator of the wing passes4 7,pectoralis secundus47 #h1 ,broken end of scapula4 ,b4 #a1 ,ligamentum transversum4 #b1 ,ligamentum laterale cubiti externum4 #c1 ,ligamentum annulare radii4 #d1 ,ligamentum cubiti teres4 #e1 ,a portion of the ligamentum capsulare cubiti4 #f1 ,distal extremity of humerus4 #g1 ,ulna4 #h1 ,radius4 ,c4 ,muscles of the outside surface of the arm4 #a1 ,tensor patagii longus4 #b1 ,extensor digitorum communis4 #c1 ,tensor patagii brevis4 #d1 ,anconeus4 #e1 ,flexor carpi ulnaris4 #f1 ,biceps4 #g1 ,triceps4 #h4 ,deltoid4 #i1 ,brachialis anticus4 #aj1 ,flexor metacarpi radialis4 #aa1 ,extensor ossis metacarpi pollicis4 #ab1 ,extensor metacarpi radialis longior4 #ac1 ,extensor indicis longus4 ,the ligamentum ulnare carpi radialis is a short ribbon-like ligament which passes over the above-mentioned ligaments and is attached to the inner surface of the os carpus radialis4 ,the ligamentum ulnare carpi radialis internum is a strong ligament which originates on the inner part of the elbow4 ,it extends to the upper rim of the base of the main digit4 ,the ligamentum radiale carpi radialis externum originates on the outside of the head of the middle digit and inserts to the superior tuberculum carpi radialis of the radius4 ,the ligamentum carpi radialis internum1 a short ligament1 extends from the inside of the head of the main digit to the inner rim of the carpi radialis4 ,the ligamentum carpi interosseum is located between the carpal bones4 ,the ligamentum ulnare metacarpi internum is spread out between the processus styloideus of the ulna and the tuberositas muscularis on the upper side of the middle finger base at a point where the second and the third metacarpi separate4 ,the ligamentum ulnare metacarpi externum extends from the tubercle of the distal extremity of the ulna1 on the dorsal side1 to the tubercle on the base of the metacarpus4 ,ligamentum radiale metacarpi extends from the head of the inner digit to a point near the tuberculum muscularis of the radius4 ,the ligamentum transversum ossis carpi radialis et metacarpi is located between the inferior tuberculum ossis carpi radialis and the first metacarpal bone4 ,there is another ligament between the tuberculum superiorus carpi radialis and the first metacarpal bone4 ,the ligamentum ossis carpi radialis internum et metacarpi extends from the inner surface of the carpus radialis to the tuberositas muscularis of the radius4 ,the ligamentum ossis carpi ulnaris externum et metacarpi extends from the ulnar carpal bone to the tuberculum of the metacarpal bone4 ,the ligamentum ossis carpi ulnaris internum et metacarpi extends from the processus uncinatus of the ulnar carpal bone to the tuberositas muscularis of the metacarpal bone4 ,ligaments of the ,finger4--,the ligamentum pollicare connects the thumb with the first metacarpal bone4 ,the ligamentum anterius ossis metacarpi et prim phalangis digiti secundi extends from the tuberculum articulare metacarpi1 of the proximal end of the metacarpus1 to the tuberculum articulare of the first phalanx of the second or large finger4 ,similarly attached1 are also an internal and a posterior ligament1 or ligamentum internum and ligamentum posterius4 ,the three phalanges are all provided with capsular ligaments1 or ligamenta capsularia1 which bind together the several phalanges4 ,the small or third finger is connected to the metacarpus by a capsular ligament1 the ligamentum capsulare1 and by an interosseous ligament1 or ligamentum interosseum digitorum1 to the first phalanx of the second finger4 ,ligaments of the ,pelvis4--,the obturator foramen1 formed by the ilium and the ischium1 is covered by a broad membranous ligament 7,fig4 #d1 ,no4 #bi74 ,the oblong foramen1 or foramen oblongum1 and the foramen ischiadicum1 formed by the ischium and the pubis are covered by broad membranous ligaments 7,fig4 #d1 ,nos4 #bi and #fj74 ,poupart's ligament or ligamentum ,poupartii1 quite small in fowls1 extends from the anterior lower rim of the ilium to the pelvic cavity1 and is inserted at the bottom of the acetabulum4 ,another broad ligament originates from the posterior rim of the ischium and is attached to the square surface of the first coccygeal vertebra4 ,the ilio-pubic ligament extends from the pubic spine to the last rudimentary rib4 ,ligaments of the ,hip-joint 7,fig4 #be1 ,f74--,the hip-joint is made up of the ilium1 ischium1 pubis and femur and is a deep ball-and-socket joint4 ,the cavity or acetabulum is called a cotyloid cavity4 ,the hip-joint is provided with three ligaments4 ,the ligamentum capsulare femoris is attached around the rim of the cotyloid cavity and around the rim of the articular head of the femur 7,fig4 #be1 ,no4 ,f1 #d74 ,the ligamentum teres1 or round ligament1 is a very short ligament which closes the hole at the floor of the cotyloid cavity1 at which point it is attached4 ,it is also attached to the head of the femur4 ,the ligamentum ilio-sacrale strengthens the hip-joint capsule4 ,it passes from the lower anterior rim of the os ilii1 extending over the capsule to the neck of the femur to which it is attached4 ,the ,ligaments of the ,knee-joint 7,figs4 #af and #ag74--,the knee-joint is made up of the femur1 patella1 tibia and fibula1 and is provided with the following ligaments3 ,the ligamentum extero-laterale genu is a strong ligament extending from the condylus externus femoris1 or external femoral condyle to the outer surface of the head of the fibula1 or capitulum fibul4 ,from this head there passes inward1 a strong ligament to a point between the femur and fibula 7,fig4 #be1 ,no4 ,d1 #d74 ,illustration3 ,,fig4 #af4--,ligaments and muscles of the hind extremity4 ,a4 ,a transverse section through the tibial or tarsal cartilage1 front view4 #a1 ,gastrocnemius tendon4 #b1 ,flexor perforatus annularis primus pedis4 #c1 ,flexor perforans digitorum profundus4 #d1 ,flexor perforatus indicis secundi pedis4 #e1 ,extensor longus hallucis4 #f1 ,the articular surface4 #g1 ,ligamentum capsulare ossis tarsi4 #h1 ,flexor perforatus medius secundus pedis4 #i1 ,flexor perforatus indicis secundus pedis4 #aj1 ,tendons of the extensor muscles4 ,b4 ,knee-joint4 ,inside view of femoro-tibial articulation4 #a1 ,anterior ligamentum cruciatum4 #b1 ,internal ligamentum laterale genu4 #c1 ,anterior patellar ligament4 #d1 ,patella4 #e1 ,distal end of femur4 #f1 ,proximal end of tibia4 #g1 ,location of meniscus or pad of fibrocartilage4 ,c4 ,anterior view of tibio-tarsal articulation4 #a1 ,distal end of tibia4 #b1 ,its articular surface4 #c1 ,ligamentum anticum4 #d1 ,proximal end of metacarpus4 #f1 ,pad of fibrocartilage4 ,d4 ,the dorsal surface of the coccyx4 #a1 ,the bilobate oil gland4 #b1 ,its duct4 #c1 ,levator coccygis4 ,e4 ,inside view of pelvis and thigh4 #a1 ,obturator internus4 #b1 ,ambiens4 #c1 ,vastus internus4 #d1 ,internal ligamentum laterale genu4 #e1 ,tibialis anticus4 #f1 ,loop through which the tibialis anticus passes4 #g1 ,adductors of the thigh4 #h1 ,loop for the extensor tendon4 ,the ligamentum intero-laterale genu extends from the outer surface of the internal condyle of the tibia1 or condylus internus tibi4 ,it gives off a thin ligamentous slip which enters the joint and is attached to the inner half-moon shaped pad of fibrous cartilage1 or meniscus1 which it draws backward by the flexion of the knee 7,fig4 #af1 ,no4 ,b1 #b74 ,the ligamentum popliteum arises from the fossa poplitea of the distal extremity of the femur and extends downward to the posterior rim of the head of the tibia4 ,the anterior ligamentum cruciatum genu originates from the fossa poplitea and extends outward antero-laterally to the rim of the head of the tibia 7,fig4 #be1 ,no4 #f74 ,the posterior ligamentum cruciatum genu is a short1 strong ligament which originates from the cavity of the internal condyle of the femur1 or condylus internus femoris1 and inserts into the internal glenoid cavity of the tibia 7,fig4 #be1 ,no4 #a7 or cavitas glenoidalis interna4 ,the meniscus of the femoro-tibial articulation is divided into four parts1 as follows3 first1 the internal adhesio cornu antici cartilaginis lunat2 second1 the posterior adhesio cornu antici cartilaginis lunat2 third1 the external cornu cartilaginis lunat2 fourth1 the anterior cornu antici cartilaginis lunat4 ,the latter originates between the condyles and passes around the ligamentum cruciatum genu posticum 7,fig4 #af1 ,no4 ,b1 #g74 ,the inner semi-lunar fibrous cartilage is well developed and is joined by two ligaments between the femoral and the tibial surfaces 7,fig4 #be1 ,no4 #a74 ,the external semi-lunar cartilage lies in a cavity between the external femoral condyle and the head of the fibula 7,fig4 #be1 ,no4 #b74 ,the fibrous cartilages are bound posteriorly by a ligament1 and by a second ligament to the head of the fibula1 or capitulum fibul4 ,both pads of fibrous cartilage are connected by a transverse ligament called the ligamentum transversale commune 7,fig4 #be1 ,no4 #e74 ,the patella is provided with several ligaments1 as follows3 ,the anterior patellar ligament1 broad1 strong1 and irregular in thickness1 extends from the inferior margin of the patella to the rim of the second tibial crest 7,fig4 #af1 ,no4 ,b1 #c74 ,the ligamentum capsulare capituli fibul is spread out between the head of the fibula1 or capitulum fibul1 and the superficies glenoidalis peronea tibi4 ,illustration3 ,,fig4 #ag4--,muscles and tendons of the head and posterior extremity4 ,a4 ,section of neck with superficial muscles removed4 #a1 ,obliquo-transversales4 #b1 ,interspinales4 #c1 ,intertransversales4 #d1 ,interarticulares4 ,b4 ,head showing muscles4 #a1 ,beak4 #b1 ,nostril4 #c1 ,tongue4 #d1 ,sublingual salivary gland4 #e1 ,pterygoideus4 #f1 ,stylo-hyoideus4 #g1 ,temporal4 #h1 ,flexor capitis inferior4 #i1 ,rectus capitis lateralis4 #aj1 ,rectus capitis posticus major4 #aa1 ,trachelo-mastoideus4 #ab1 ,eye4 #ac1 ,mylo-hyoideus4 #ad1 ,genio-hyoideus4 #ae1 ,biventer maxilla4 #af1 ,digastricus4 #ag1 ,rectus capitis anterior minor4 ,c4 ,foot of hen showing tendons4 #a1 ,flexor perforans digitorum profundus4 #b1 ,flexor perforatus medius primus pedis4 #c1 ,sheath at joint through which tendon passes4 #d1 ,flexor perforatus indicis primus pedis4 #e1 ,flexor perforatus medius secundus pedis4 #f1 ,flexor perforatus annularis primus pedis4 #g1 ,flexor longus hallucis4 ,d4 ,outside view of leg of hen4 #a1 ,biceps flexor cruris4 #b1 ,semitendinosus4 #c1 ,loop through which biceps flexor cruris passes4 #d1 ,tibialis anticus4 #e1 ,flexor perforatus indicis secundus pedis4 #f1 ,flexor perforatus medius primus pedis4 #g1 ,gastrocnemius4 #h1 ,flexor perforatus annularis primus pedis4 #i1 ,flexor perforatus medius secundus pedis4 #aj1 ,extensor longus hallucis4 ,the ligamentum tibio-fibulare extends from the head of the fibula1 or capitulum fibul1 to the inner surface of the external crest1 or crista externa tibi1 of the tibia 7,fig4 #be1 ,no4 #c74 ,the ligamentum interosseum is a delicate ligament located between the tibia and fibula 7,fig4 #be1 ,no4 #d7 which very early becomes ossified4 ,ligaments of the ,tibio-metatarsal ,joint 7,fig4 #af74--,the tibio-tarsal joint is made up of the tibia and metatarsus4 ,the ligamentum capsulare ossis tibio-metatarsi connects the tibia and the metatarsus and surrounds the joint 7,fig4 #af1 ,nos4 ,a1 #g and ,c1 #g74 ,the ligamentum externum1 a long strong ligament1 originates on the upper and outer surface of the external condyle1 or condylus externus of the tibia and is attached to the upper rim of the os metatarsi 7,fig4 #bc1 ,no4 #ae74 ,the ligamentum anticum is spread out between the fossa intercondyloidea of the tibia and the tuberculum ossis metatarsi of the proximal end of the metatarsus 7,fig4 #af1 ,no4 ,c1 #c74 ,just posterior to this ligament1 there is an interosseous ligament1 the ligamentum interosseum4 ,a semi-lunar pad of fibrous cartilage1 the cartilago semi-lunaris is located between the outer distal extremity of the tibia and upper articular surface of the metatarsus 7,fig4 #af1 ,no4 ,c1 #f74 ,its concave portion is directed anteriorly and receives an insertion from the ligamentum externum1 or external ligament4 ,the tendon ,achillis 7,fig4 #af1 ,no4 ,a1 #a7 may become ossified4 ,ligaments of the ,toes 7,fig4 #af74--;,in addition to the capsular ligaments1 which all true joints have1 we find the following in connection with the toes3 ,the ligamentum superius and the ligamentum inferius connect the second toe with the great toe1 or hallux4 ,the ligamentum laterale externum and the ligamentum laterale internum unite the bases of the second1 third and fourth toes to the lateral faces of the trochleas of the inferior extremity of the metatarsus4 ,the bases of the toes are held together by the ligamenta transversa4 ,all the rest of the toes are held together by the ligamenta capsularia digitorum pedis and by two lateral ligaments1 namely3 the ligamentum laterale externum and the ligamentum laterale internum4 ,,myology ,kinds and ,structure of ,muscles4--,muscles are highly specialized structures which have the property of contractility when stimulated1 and thus produce motion4 ,muscular tissue is sometimes called flesh4 ,two kinds of muscles are recognized2 muscles of locomotion and visceral muscles4 ,the muscles of locomotion may be in masses of different shape attached to the skin1 the dermal1 or to the skin and skeletal structure1 the dermo-osseous1 or from one bone to another1 the skeletal4 ,the visceral muscles form sheets and make up a portion of the wall of many of the hollow organs1 such as the intestines1 the stomach1 the gizzard1 the esophagus1 and the blood-vessels4 ,a special type of muscle forms the heart4 ,when classified with reference to structure1 muscular tissue is divided into three types1 as follows3 voluntary-striated1 involuntary1 and involuntary-striated4 ,the microscopic examination of each of these types of muscle shows it to be made up of fibers1 these fibers to be made up of muscle cells1 the muscle cell to be inclosed in a delicate tubular sheath1 or membrane1 called the sarcolemma4 ,this membrane1 tough and elastic1 isolates each fiber4 ,the bundles of fibers1 called fasciculi1 are surrounded by a fibrous sheath1 which is called the perimysium internum2 and the entire muscle has likewise an investing sheath of connective tissue1 called the perimysium externum4 ,the muscular cells show a longitudinal striation marking the fibrill1 and they also show a cross striation4 ,nuclei are found just beneath the covering1 or sarcolemma1 in the striated muscle cell 7,fig4 #gg1 ,no4 #b74 ,in the involuntary and in the involuntary-striated muscle cell1 the nuclei are centrally located4 ,the voluntary-striated muscles consist of cylindrical fibers and with a few exceptions1 are under the control of the will4 ,a muscle of this type1 the regular skeletal form1 usually has at each extremity a fibrous structure1 called a tendon1 by means of which it is attached to the bones4 ,the intermediate fleshy portion of the muscle1 in case of considerable bulk1 is called the belly of the muscle4 ,the involuntary1 non-striated1 or smooth muscle1 cells are spindle-shaped1 long1 and pale in color 7,fig4 #gg1 ,no4 #a74 ,the cells lie end to end forming fibers4 ,these fibers do not terminate in tendons1 but are arranged in sheets and aid in forming the walls of the digestive tract1 to which they give the power of contraction and expansion4 ,involuntary-striated1 or heart muscle 7,fig4 #gg1 ,no4 #d71 occupies an intermediate position between the two muscles just described4 ,it is composed of cells which branch1 are somewhat rectangular4 ,they possess both longitudinal and transverse striation4 ,among the fibers is found a small amount of connective tissue1 as in the former types of muscle1 which gives support to the blood-vessels and nerves4 ,fascia4--,the term fascia is applied to membranous expansions1 differing materially in strength1 texture1 and relations4 ,fascia is composed of loosely arranged white fibrous connective tissue4 ,at least two layers may usually be distinguished1 the superficial fascia and the deep fascia4 ,below the skin is the superficial fascia1 which forms a continuous covering over the whole body and serves to attach the skin to the underlying structure4 ,the deep fascia more densely constructed1 may be attached to the skeleton1 ligaments1 and tendons4 ,when the fascia spreads out1 becomes denser1 and acts as a continuation of a muscle1 it is called an aponeurosis4 ,the ,muscular ,nomenclature4--,in the fowl there are #afb muscles1 single or in pairs4 ,these muscles are named from their location1 as the lingualis2 others from their attachments1 as the dermo-temporalis2 some from their form1 as the rhomboideus2 others from their use1 as the flexor or extensor2 and still others from their direction1 as the transversus4 ,,the ,,dermal ,,muscles ,birds are provided with a system of delicate muscles divided into numerous fasciculi1 which harmoniously act upon the feather quills and collectively agitate the plumage4 ,these are the dermal muscles4 ,this group is divided into two subgroups3 the true dermal muscles1 that is1 those that have their origin and insertion to the under surface of the skin2 and the dermo-osseous1 those that originate on the surface of some bone and insert to the inner surface of the skin4 ,,true ,,dermal ,,muscles ,dermo-frontalis ,dermo-dorsalis ,dermo-tensor patagii ,dermo-humeralis ,dermo-pectoralis ,dermo-frontalis4#c ,location4--,this muscle is somewhat rudimentary and may be entirely absent4 ,it is located in the frontal region and is about #b or #c centimeters long and not so wide4 ,footnote #c3 ,the classification of ,shufeldt is used4 ,origin and ,insertion4--,closely attached to the skin4 ,shape4--,flat and rather rectangular4 ,relations4--,superiorly with the skin and inferiorly with the frontal bones4 ,action4--,by contraction the feathers on the top of the head lie flat4 ,those above the eyes are elevated4 ,dermo-dorsalis4 ,location4--,in the median line of the neck and back4 ,origin and ,insertion4--,adhering closely to the skin1 it generally becomes lost at the occiput2 it is most highly developed in the mid-cervical region1 and it gradually disappears over the caudal region4 ,shape4--,delicate and ribbon-shaped4 ,relations4--,superiorly it is attached to the skin4 ,fat sometimes surrounds the muscle4 ,action4--,by contraction it raises the feathers along the superior part of the neck and dorsal region4 ,dermo-tensor ,patagii4 ,location4--,between the root of the neck and top of the shoulder4 ,origin and ,insertion4--,attached to the skin in the region of the anterior part of the root of the neck1 some fibers passing obliquely upward and blend with fibers of the dermo-temporalis4 ,it blends1 by a slender tendon1 with that of the tensor patagii longus4 ,shape4--,a bundle of muscular fibers later becomes thin1 delicate1 and triangular in shape4 ,relations4--,externally to the skin4 ,action4--,auxiliary to the tensor patagii longus4 ,a tensor of this region4 ,the patagii are associated with the wing fold of skin which fills the angle between the arm and forearm4 ,this fold contains elastic tissue and muscle4 ,dermo-humeralis4 ,location4--,lateral thoracic region4 ,origin and ,insertion4--,fan-like delicate fibers from the skin in the abdominal integument1 contracting into a long narrow fasciculus of fibers1 again spreading out in fan-shape to be inserted to the tendon of the pectoralis major1 just below its insertion4 ,shape4--,triangular1 fan-shape4 ,relations4--,superiorly with the skin4 ,action4--,controls the skin in this region4 ,the anterior end being fixed1 the muscles are raised2 and the posterior end acting as the fixed point1 the feathers are caused to lie close to the body4 ,dermo-pectoralis4 ,location4--,on each side of the chest1 lying in a longitudinal manner4 ,origin and ,insertion4--,attached to the skin on either side of the thorax corresponding to the dermo-dorsalis4 ,anteriorly it disappears over the region of the origin of the cleido-trachealis1 and posteriorly just behind the tips of the post-pubic parts of the pelvis4 ,shape4--,thin1 delicate4 ,relations4--,superiorly with the skin4 ,action4--,the anterior part acting as the fixed point1 the feathers of the chest are raised2 and the posterior end acting as the fixed point1 the feathers are made to lie flat4 ,,the ,,dermo-,,osseous ,,muscles ,dermo-temporalis ,platysma myoides ,dermo-cleido dorsalis ,cleido-trachealis ,dermo-spinalis ,dermo-iliacus ,dermo-ulnaris ,dermo-temporalis 7,fig4 #ah1 ,no4 #a74 ,location4--,from the temporal region down the side of the neck to the anterior part of the thoracic region4 ,origin4--,by a broad tendinous attachment from a small depression above and anterior to the temporal fossa4 ,from here the fibers pass upward and backward and then downward4 ,insertion4--,a few fibers blend with those of the cleido-trachealis4 ,the fibers are then lost upon the skin in front and opposite the shoulder-joint4 ,some of the fibers blend with those of the dermo-tensor patagii4 ,shape4--,long1 flat1 and ribbon-shaped4 ,the lower portion consists of delicate fibers4 ,relations4--,superior to the temporal muscle and sphenotic process4 ,superior to the cleido-trachealis and inferiorly to the shoulder-joint4 ,the superior portion touches the skin throughout its entire length4 ,action4--,a tensor of the lateral cervical integument4 ,it is an auxiliary to the tensor patagii4 ,platysma ,myoides4 ,location4--,the inferior portion of the throat4 ,origin4--,from the lower margin of the rami of the jaw4 ,just inferior to the attachment of the masseter4 ,illustration3 ,,fig4 #ah4--,muscles of the upper neck region1 #a1 ,dermo-temporalis4 #b1 ,cornu of the os hyoideum4 #c1 ,carotid artery4 #d1 ,jugular vein4 #e1 ,pneumogastric nerve4 #f1 ,esophagus4 #g1 ,trachea4 ,insertion4--,from the point of origin it spreads out into a thin fan-like layer and meets its fellow in the median raphe4 ,it is attached to the skin in this region4 ,shape4--,a very thin fan-shaped muscle4 ,relations4--,closely adherent to the skin4 ,action4--,assists in supporting the lingual apparatus and superior larynx4 ,compresses and elevates the part4 ,dermo-cleido ,dorsalis4 ,location4--,anterior shoulder region4 ,origin4--,from the upper mesial part of the clavicular bone4 ,insertion4--,three fasciculi forming a fan-like arrangement attached to the skin in the shoulder-joint and scapular region4 ,the extremities of the fasciculi may meet in the median line of the dorsal region and merge with the dermo-dorsalis4 ,shape4--,three fasciculi forming a fan-shaped radiation4 ,relations4--,superiorly with the skin4 ,inferiorly with the shoulder-joint4 ,action4--,contracting with the origin as the fixed point1 they brace the skin over the forepart of the back4 ,with the integumental attachment as the fixed point1 they aid in the act of respiration4 ,cleido-trachealis4 ,location4--,extending from the shoulder to the superior laryngeal region4 ,origin4--,from a small area on the antero-inner part of the middle of the arm of the furcula4 ,insertion4--,the fibers pass upward and become flattened and attached to the skin and dermo-temporalis muscle4 ,they touch each other on the anterior border of the superior larynx1 the trachea1 and the skin over these parts4 ,shape4--,a slender bundle of muscles4 ,relations4--,superiorly the skin1 and internally the larynx and the trachea4 ,action4--,controls the skin region of this part of the neck4 ,dermo-spinalis4 ,location4--,in the region of the shoulder4 ,origin4--,in an attenuated fascia from the crest of the neural spines of the first1 the second1 and the third dorsal vertebr4 ,insertion4--,to the skin in a broad pale stratum1 over the scapular region4 ,shape4--,thin1 pale1 and very delicate4 ,relations4--,superiorly with the skin1 and inferiorly with the shoulder4 ,action4--,controls the skin of the region4 ,dermo-iliacus4 ,location4--,along the back on either side of the spine4 ,origin4--,from the inner angle of the marginal portion of the antero-dorsal border of the ilium4 ,insertion4--,passing forward as a delicate band it spreads out and becomes lost in the skin of the shoulder region4 ,shape4--,thin1 delicate1 and ribbon-shaped4 ,relations4--,superiorly with the skin4 ,action4--,if the posterior end is fixed1 it will cause the feathers to lie close to the skin4 ,its action would then be opposite to the dermo-dorsalis4 ,dermo-ulnaris4 ,location4--,outer surface of the anterior upper costal and the posterior humeral region4 ,origin4--,by a thin fascia from the outer part of the third and the fourth true ribs at the base of their epineural appendages4 ,also from the fascia between them4 ,insertion4--,the fibers pass forward and upward as a thick muscular bundle and is loosely attached to the skin at a point just back of the humerus4 ,the tendon later becomes spread out and attached to the fascia as far as the elbow-joint4 ,it covers the olecranon of the ulna4 ,shape4--,at first rather thick1 fascicular-like2 later becomes tendinous2 and at its attachment it becomes spread out over the olecranon4 ,relation4--,inferiorly with the ribs and humerus1 and externally with the skin4 ,action4--,a depressor of the humeral region4 ,,the ,,skeletal ,,muscles ,,the ,,muscles ,,of ,,the ,,head ,temporal ,masseter ,biventer maxill ,entotympanicus ,pterygoideus internus ,pterygoideus externus ,digastricus ,temporal 7,fig4 #ai1 ,no4 #d74 ,location4--,occupies the temporal fossa4 ,origin4--,from the mesian line of the sphenotic process1 and the adjacent wall of the orbit4 ,insertion4--,the fibers passing downward and forward blend with the fibers of the masseter4 ,inferiorly it inserts by a tendon to the coranoid process upon the superior ramal margin of the mandible4 ,shape4--,fan-shaped with broad portion uppermost4 ,relations4--,it occupies the temporal fossa4 ,it is related superiorly with the dermo-temporalis and skin4 ,inferiorly1 with the biventer maxill and the masseter4 ,action4--,it aids in closing the jaw4 ,masseter 7,fig4 #ai1 ,no4 #a74 ,location4--,occupies the supero-lateral portion of the surface of the lower jaw4 ,origin4--,in two portions3 the first1 by a broad and thin tendon from the entire length of the bony ridge above the external auditory meatus1 from the squamosal process1 and from the outer portion of the quadrate bone2 the second1 from the side and under border of the zygoma4 ,insertion4--,the first portion3 ,the fibers pass downward and forward beneath the zygoma2 a few of the fibers blend with those of the temporal2 one tendon inserts to a small tubercle on the upper border of the jaw behind the coronoid process1 and by fleshy insertion to the outer side of the ramus of the lower jaw1 quite as far forward as the horny portion of the beak4 ,the second portion3 by a small tendon to the mandible on its upper border immediately in front of the articular portion4 ,shape4--,flat1 and elongate4 ,somewhat fleshy4 ,relations4--,superiorly with the temporal1 and inferiorly with the biventer maxill and stylo-hyoideus4 ,externally with the skin1 and internally with the jaw bone4 ,action4--,aids in closing the jaw4 ,biventer ,maxill 7,fig4 #ai1 ,no4 #c74 ,location4--,covers the outer posterior portion of the mandible4 ,origin4--,it arises in two portions3 ,the first1 from a ridge bounding the posterior part of the auditory canal2 the second1 from a depression of the mesial side4 ,these two parts blend and extend downward and forward4 ,insertion4--,to the posterior part of the articular end of the mandible4 ,shape4--,a curved fleshy mass4 ,relations4--,superiorly with the temporal and stylo-hyoideus4 ,posteriorly with the digastricus and genio-hyoideus4 ,internally with the jaw bone1 and externally with the skin4 ,action4--,it aids in opening the jaw4 ,entotympanic4 ,location4--,posterior to the pterygoid4 ,origin4--,from the side of the basi-sphenoid and from the base of the rostrum immediately beyond it4 ,insertion4--,the fibers pass downward and forward1 and insert by a double tendinous slip4 ,one slip inserts to a spine-like process on the upper side of the pterygoid1 and the other to the quadrato-pterygoidean articulation4 ,shape4--,spindle-shaped4 ,relations4--,anteriorly with the pterygoid4 ,internally and posteriorly with the basi-sphenoid4 ,externally with the pterygoideus internus4 ,action4--,aids in raising the upper mandible by pulling forward the quadratus and pterygoidean against the palatines4 ,pterygoideus ,internus 7,fig4 #ag1 ,no4 ,b1 #e74 7,synonym4--,pterygoideus medialis4#d7 ,footnote #d3 ,according to international veterinary nomenclature4 ,location4--,a muscular mass at the roof of the mouth4 ,origin4--,from the major part of the surface of the palatine bone and the distal head and shaft of the pterygoid and the sphenoidal projection4 ,insertion4--,by a tendon to the antero-internal part of the articular part of the mandible4 ,shape4--,fusiform with a thick fleshy belly4 ,relations4--,superiorly with the palatine1 the pterygoid1 and the sphenoid bones4 ,inferiorly with the skin4 ,action4--,it aids in closing the jaw4 ,pterygoideus ,externus4 7,synonym4--,pterygoideus lateralis47 ,location4--,supero-external to the pterygoideus internus4 ,origin4--,from the outer part of the extremity of the orbital process of the quadrate4 ,insertion4--,the fibers pass downward1 outward and forward and are inserted to the inner part of the mandibular ramus4 ,shape4--,a small round bundle4 ,relations4--,inferiorly with the pterygoideus internus4 ,externally with the inferior maxilla4 ,action4--,aids in closing the jaw4 ,digastricus 7,fig4 #ag1 ,no4 ,b1 #af74 ,location4--,extends from the basi-temporal to the side of the neck4 ,origin4--,from the external lateral angle of the basi-temporal4 ,insertion4--,opposite the angle of the jaw the fibers spread out in fan-like arrangement4 ,the muscle meets its fellow of the opposite side2 extends longitudinally over the superior larynx1 for some distance down the neck4 ,shape4--,thin and ribbon-shaped4 ,relations4--,externally to the platysma myoides4 ,the anterior fasciculi blend with those of the mylo-hyoideus2 internally with the larynx at the upper part4 ,action4--,to raise the trachea and hyoid apparatus against the pharynx4 ,,the ,,muscles ,,of ,,the ,,tongue ,mylo-hyoideus ,stylo-hyoideus ,genio-hyoideus ,cerato-hyoideus ,sterno-hyoideus ,depressor-glossus ,cerato-glossus ,hyoideus transversus ,mylo-hyoideus4 ,location4--,the forepart of the inter-ramal space4 ,origin4--,from the inner side of the lower jaw at a point just above the lower border and the inturned edge of the horny sheath of the beak4 ,insertion4--,by aponeurosis to the under side of the hyoid1 on the median line between the first and the second basi-branchial4 ,shape4--,thin1 flat1 and delicate4 ,relations4--,inferiorly with the skin4 ,thin and rather broad1 it meets its fellow of the opposite side4 ,laterally with the rami of the jaw4 ,superiorly with the hyoid apparatus4 ,action4--,lifts the tongue upward against the roof of the mouth4 ,stylo-hyoideus 7,fig4 #ag1 ,no4 ,b1 #f74 ,location4--,supero-posterior to the hyoid apparatus4 ,origin4--,from the outer portion of the articular enlargement of the lower jaw4 ,insertion4--,by a tendon to the basi-branchial of the thyro-hyal4 ,shape4--,a long transversely flattened fasciculus4 ,relations4--,supero-posterior part of the hyoid apparatus along side the genio-hyoideus and the cerato-hyoideus4 ,action4--,singly1 pulls the tongue to one side2 acting with its fellow1 pulls the tongue upward4 ,genio-hyoideus 7,fig4 #i1 ,no4 #g74 ,location4--,supero-posterior to the hyoid apparatus4 ,origin4--,from the anterior portion of the inner side of the lower jaw4 ,insertion4--,to the middle of the outer side of the basi-branchial of the corner of the os hyoides which cornu it completely envelops4 ,shape4--,a long1 rather thick fasciculus4 ,relations4--,with the stylo-hyoideus and cerato-hyoideus4 ,action4--,protrudes the tongue from the mouth4 ,cerato-hyoideus 7,fig4 #i1 ,no4 #h74 7,synonym4--,kerato-hyoideus47 ,location4--,inferior to the hyoid apparatus4 ,origin4--,by a delicate tendinous slip from the under side of the shaft of the basi-hyal element of the hyoid apparatus4 ,insertion4--,to a small elevation on the under side of the anterior end of the glosso-hyal4 ,shape4--,a small round muscular fasciculus becoming tendinous in its anterior half4 ,relations4--,superiorly with the hyoid apparatus4 ,action4--,singly1 pulls the tongue to one side2 acting with its fellow1 depresses the tongue4 ,sterno-hyoideus4 ,location4--,inferior to the hyoid apparatus4 ,origin4--,from the outer anterior surface of the thyroid bone of the superior larynx4 ,insertion4--,to the anterior part of the basi-hyal4 ,shape4--,at first broad and rather fleshy1 becomes contracted and somewhat tendinous4 ,relations4--,inferior to the hyoid apparatus and superior larynx4 ,action4--,when the larynx is fixed1 acting alone deflects the tongue laterally2 acting with its fellow1 depresses the tongue4 ,if the base of the tongue is fixed the two pull the larynx forward4 ,hence muscles of deglutition4 ,depressor-glossus4 ,location4--,superior to the basi-hyal4 ,origin4--,from the under portion of the basi-hyal4 ,insertion4--,to under part of the glosso-hyal4 ,shape4--,small1 short4 ,relations4--,superiorly with the basi-hyal and glosso-hyal bones4 ,action4--,depresses the tip of the tongue and elevates the base4 ,cerato-glossus4 ,location4--,on the upper portion of the cornu of the hyoid4 ,origin4--,one-half of the surface of the first basi-branchial4 ,insertion4--,to the upper side of the shaft of the cerato-branchial element of the hyoid apparatus4 ,shape4--,a small muscular fasciculus4 ,relations4--,supero-laterally to the cerato-branchial element4 ,action4--,elevates the cornua of the hyoid arches and presses them against the skull4 ,hyoideus ,transversus 7,fig4 #i1 ,no4 #i and #aj74 ,location4--,envelops the spur process of the euro-hyal4 ,origin and ,insertion4--,it extends from the inner side of one cornu to the spur process4 ,shape4--,thin1 flat4 ,relations4--,posterior to the euro-hyal1 which it envelops1 and between the cornua of the os hyoides4 ,action4--,approximates the cornua of the os hyoides4 ,,the ,,cervical ,,muscles ,complexus ,rectus capitis anticus minor ,flexor capitis inferior ,rectus capitis posticus major ,biventer cervicis ,longus colli posticus ,obliquus colli ,longus colli anterior ,rectus capitis lateralis ,trachelo-mastoideus ,interspinales ,interarticulares ,obliquo-transversales ,intertransversales ,scalenus medius ,complexus 7,fig4 #ai1 ,no4 #e74 ,location4--,supero-lateral portion of the neck4 ,origin4--,by three tendinous slips from the antero-lateral portion of the transverse process of the fourth1 the fifth1 and the sixth cervical vertebr4 ,insertion4--,the muscular fibers pass around the neck and meet their fellows in the median line in a fascia formation4 ,the thin tendinous sheet inserts into the occiput just above the occipital ridge4 ,shape4--,from point of origin this muscle expands into a broad sheet4 ,relations4--,it overlies the muscles of the occipital region4 ,action4--,it extends the head4 ,rectus ,capitis ,anticus ,minor 7,fig4 #ai1 ,no4 #h74 7,synonym4--,rectus capitis ventralis minor47 ,location4--,infero-lateral portion of the neck4 ,origin4--,from the apices of the hyapophyses of the second1 the third1 and the fourth cervical vertebr4 ,insertion4--,to the occiput just below the complexus4 ,shape4--,a long and rather thick fasciculus4 ,relations4--,externally with the skin4 ,the tendinous slips of origin pass between the flexor capitis inferior and longus colli anterior4 ,action4--,extends the head4 ,flexor ,capitis ,inferior 7,fig4 #ai1 ,no4 #g74 ,location4--,antero-inferior part of the neck4 ,origin4--,from the apices of the hyapophyses of the second1 the third1 and the fourth cervical vertebr4 ,insertion4--,to the triangular area on the basi-temporal of the base of the cranium4 ,shape4--,at first tendinous1 becomes somewhat fleshy as it passes forward4 ,illustration3 ,,fig4 #ai4--,muscles of the head and neck4 #a1 ,masseter muscle4 #b1 ,infraorbital sinus4 #c1 ,biventer maxilla4 #d1 ,temporalis4 #e1 ,complexus4 #f1 ,rectus capitis posticus major4 #g1 ,flexor capitis inferior4 #h1 ,rectus capitis anticus minor4 #i1 ,biventer cervicis4 #aj1 ,longus colli posticus4 #aa1 ,obliquus colli4 #ab1 ,intertransversales4 #ac1 ,longus colli anterior4 #ad1 ,lateral temporo-maxillary ligament4 #ae1 ,lateral ligament of the jaw4 #af1 ,trachelo-mastoideus4 #ag1 ,rectus capitis lateralis4 #ah1 ,scalenus medius4 #ai1 ,rhomboideus4 #bj1 ,trapezius4 #ba1 ,location of scapula4 #bb1 ,supraspinatus4 #bc1 ,teres et ,infraspinatus4 ,relations4--,antero-inferior portion of the neck close to the rectus capitis anticus minor4 ,action4--,flexes the head upon the neck4 ,rectus ,capitis ,posticus ,major 7,fig4 #ai1 ,no4 #f74 7,synonym4--,rectus capitis dorsalis major47 ,location4--,supero-lateral area on the anterior portion of the neck4 ,origin4--,from the median anterior aspect of the second cervical vertebra1 and the supero-anterior border of the neural canal4 ,insertion4--,to the crescent-shaped area at the back of the skull4 ,shape4--,short1 thick1 fleshy bundle4 ,relations4--,superiorly with the complexus2 inferiorly with the trachelo-mastoideus and the vertebr4 ,action4--,singly1 pulls the head to one side2 acting with its fellow1 extends the head4 ,biventer ,cervicis 7,fig4 #ai1 ,no4 #i74 ,location4--,occupies the superior part of the neck4 ,origin4--,from the side of the neural spine of the first dorsal vertebra1 and from the adjacent tendon of the longus colli posticus4 ,insertion4--,to the occiput4 ,shape4--,tendinous in the middle with a more or less spindle-shaped belly at each end4 ,relations4--,superior to the longus colli posticus4 ,it lies next to the skin4 ,action4--,extends the head on the neck and elevates the neck4 ,longus ,colli ,posticus 7,fig4 #ai1 ,no4 #aj74 7,synonym4--,longus colli dorsalis47 ,location4--,occupies the superior part of the neck4 ,origin4--,from the marginal edges of the summits of the neural spines of the first two dorsal vertebr4 ,insertion4--,to the transverse process of the axis1 and superior part of the cervical vertebr4 ,shape4--,a long1 somewhat narrow1 flattened muscle1 the inferior portion of which is divided into five or six fasciculi4 ,relations4--,superiorly with the biventer cervicis and inferiorly with the vertebr4 ,action4--,raises the neck upward4 ,obliquus ,colli 7,fig4 #ai1 ,no4 #aa74 ,location4--,on the lateral side of the neck4 ,origin and ,insertion4--,the first of the seven fasciculi originates from the diapophysis of the eleventh cervical vertebra1 winds obliquely over the tenth1 and is inserted into the posterior margin of the postzygapophysis of the ninth vertebra4 ,in its passage it receives the slip from the longus colli posticus4 ,the next fasciculus originates from the transverse process of the tenth cervical vertebra1 winds obliquely over the ninth vertebra1 and is inserted to the postzygapophysis of the eighth vertebra4 ,in its passage it also receives a fasciculus from the longus colli posticus4 ,the next three fasciculi originate in a similar manner being attached to similar postzygapophyses and have slips extending forward which slips are inserted to the neural spines of the alternate vertebr4 ,the sixth fasciculus originates from the transverse process of the sixth vertebra1 passing obliquely up the neck is inserted to the extremity of the diapophysis of the fourth vertebra1 the outer extremity of the transverse process of the third vertebra4 ,the seventh1 or anterior1 fasciculus originates from the transverse process of the fifth vertebra1 and is inserted to the extremity of the diapophysis of the third vertebra4 ,shape4--,short1 thick fasciculi4 ,relations4--,laterally with the vertebr4 ,inferiorly with the intertransversales4 ,superiorly with the longus colli posticus1 and externally with the skin4 ,action4--,flexes one vertebra on the other laterally4 ,longus ,colli ,anterior 7,fig4 #ai1 ,no4 #ac74 7,synonym4--,longus colli ventralis47 ,location4--,occupies the anterior portion of the neck4 ,origin and ,insertion4--,this muscle is divided into a vertical portion1 and a superior and an inferior oblique portion4 ,the vertical portion originates from the hypophyses of the tenth to the fifteenth vertebra and is inserted by a tendon to the tubercle on the inferior portion of the atlas4 ,small1 slender tendons are given off and insert to the apices of the parapophyses of the fourth to the tenth cervical vertebr4 ,there is more or less attachment to the bodies of the cervical vertebr mentioned4 ,the superior oblique portion originates from the diapophyses of the third1 the fourth1 the fifth cervical vertebr and becoming tendinous is inserted to the tubercle on the inferior portion of the body of the atlas4 ,the inferior oblique portion originates from the transverse processes of the fourth1 the fifth1 and the sixth cervical vertebr4 ,it is inserted by a slender tendon to the apex of the parapophysis of the third cervical vertebra4 ,shape4--,a long fleshy muscle extending the entire length of the neck4 ,relations4--,inferiorly with the skin and superiorly with the cervical vertebr4 ,action4--,pulls the neck downward4 ,rectus ,capitis ,lateralis 7,fig4 #ai1 ,no4 #ag74 ,location4--,the infero-lateral anterior portion of the neck4 ,origin4--,originates tendinous from the diapophysis of the third1 the fourth1 and the fifth cervical vertebr4 ,insertion4--,passes obliquely upward in front of the spinal column to the inner tubercle on the basal ridge of the basi-temporal bone1 by a subcompressed tendon4 ,shape4--,a somewhat thick fasciculus4 ,relations4--,superiorly with the trachelo-mastoideus1 inferiorly with the longus colli anterior1 and externally with the skin4 ,action4--,singly1 pulls the head down and to one side2 acting with its fellow1 pulls the head downward4 ,trachelo-mastoideus 7,fig4 #ai1 ,no4 #af74 7,synonym4--,longissimus capitis et atlantis47 ,location4--,laterally on the anterior portion of the neck4 ,origin4--,semitendinous from the diapophyses of the second1 the third1 the fourth1 and the fifth cervical vertebr4 ,insertion4--,by subcompressed tendon to the base of the cranium1 at the outer tubercle of the basal ridge of the basi-temporal4 ,shape4--,flattened from side to side2 broad at the posterior portion1 becomes angular at the anterior portion4 ,action4--,singly1 pulls the head down and to one side2 acting with its fellow1 pulls the head downward4 ,interspinales 7,fig4 #ag1 ,a1 ,no4 #b74 ,location4--,superior to the vertebra4 ,origin and ,insertion4--,a series of muscles connecting the superior neural spines of the cervical vertebr4 ,shape4--,thin1 flat4 ,relations4--,anteriorly the posterior border of the vertebr in front and posteriorly the anterior border of the succeeding vertebr1 inferiorly by the vertebr4 ,action4--,to approximate the spinous portion of the vertebr4 ,interarticulares 7,fig4 #ag1 ,no4 ,a1 #d74 ,location4--,supero-laterally to the vertebr4 ,between the postzygapophysis4 ,origin and ,insertion4--,from the posterior margin of the ring of the atlas to the postzygapophysis of the axis4 ,then in the succeeding vertebr from the postzygapophysis of the vertebra to the same of the succeeding vertebra4 ,shape4--,muscular bundle4 ,relations4--,inferiorly with the vertebr4 ,supero-laterally with the obliquo-transversales4 ,action4--,aids in approximating the vertebr in a supero-lateral direction4 ,obliquo-transversales 7,fig4 #ag1 ,a1 ,no4 #a74 ,location4--,supero-lateral to the vertebr4 ,origin and ,insertion4--,passes obliquely from the transverse process of one vertebra to the postzygapophysis of the vertebra beyond4 ,shape4--,a thin fasciculus4 ,relations4--,inferiorly with the interarticulares and laterally with the intertransversales4 ,action4--,aids in flexing the vertebr supero-laterally4 ,intertransversales 7,fig4 #ai1 ,no4 #ab74 ,location4--,laterally to the vertebr4 ,origin and ,insertion4--,extend between the transverse processes beginning at the third cervical vertebra4 ,shape4--,short1 thick4 ,relations4--,laterally the vertebr4 ,superiorly the obliquo-transversales4 ,action4--,aids in flexing the vertebr laterally4 ,scalenus ,medius 7,fig4 #ai1 ,no4 #ah74 7,synonym4--,scalenus47 ,location4--,supero-laterally to the entrance of the thorax4 ,origin4--,from the diapophysis and pleurapophysis of the eleventh cervical vertebra4 ,insertion4--,to the entire border of the first rib4 ,a few fibers pass over to the anterior free margin of the middle third of the second rib4 ,shape4--,rather pyramidal in shape with base uppermost4 ,relations4--,posteriorly with the levatores costarum4 ,internally with the longus colli4 ,action4--,when the first rib is fixed singly1 turns the neck to one side2 acting with its fellow1 extends the neck4 ,when the neck is fixed1 by drawing the first rib forward1 it acts as an inspiratory muscle4 ,,the ,,muscles ,,of ,,the ,,air ,,passages ,the ,superior ,larynx ,constrictor glottidis ,thyreo-arytenoideus ,the ,inferior ,larynx ,tracheo-lateralis ,broncho-trachealis posticus ,broncho-trachealis anticus ,broncho-trachealis brevis ,bronchialis posticus ,bronchialis anticus ,sterno-trachealis ,constrictor ,glottidis4 ,location4--,supero-anterior portion of the superior larynx4 ,origin4--,from the superior and longitudinal line of the thyroid plate4 ,insertion4--,all along the inner margin of the arytenoid bone1 and to the apex of the mid-cricoidal segment4 ,shape4--,thin1 flat sheet extending outward and upward1 and then inward4 ,relation4--,interiorly with the larynx4 ,action4--,the two muscles of this kind acting together1 close the glottis by drawing the apices of the arytenoids to the median line4 ,thyreo-arytenoideus4 ,location4--,supero-lateral portion of the superior larynx4 ,origin4--,from the entire outer margin of the thyroid plate and the outer margin of the cricoid bone4 ,insertion4--,all along the outer margin of the arytenoid bone and the outer border of the central cricoid piece4 ,shape4--,a thin1 flat sheet4 ,relations4--,infero-laterally with the superior larynx4 ,action4--,the two muscles of this kind acting together1 open the glottis by pulling the arytenoid bone outward4 ,tracheo-lateralis 7,fig4 #bj1 ,no4 #b74 ,location4--,along the lateral side of the trachea4 ,origin4--,by the union of the bronchio-trachealis posticus and bronchio-trachealis anticus1 on the lateral side of the trachea1 about #a centimeters from the bifurcation of the trachea4 ,insertion4--,in delicate fan-like structure to the side of the trachea1 near the superior larynx4 ,shape4--,thin1 ribbon-shaped1 closely attached to the trachea4 ,relations4--,internally with the trachea1 and externally with the skin and other integument4 ,action4--,acts as a brace to the sides of the trachea1 and contracting1 approximates the tracheal rings and thus shortens the trachea4 ,broncho-trachealis ,posticus 7,fig4 #ba1 ,no4 #c74 ,location4--,postero-superior portion of the trachea4 ,the fibers pass downward and backward4 ,origin4--,from the inferior end of the tracheo-lateralis4 ,insertion4--,to the end of the third half of the bronchial ring of the same side4 ,shape4--,a small fasciculus4 ,relations4--,internally with the trachea1 and externally with the skin and other integument4 ,illustration3 ,,fig4 #bj4--,the anterior pectoral region4 #a1 ,sterno-trachealis4 #b1 ,tracheo-lateralis4 #c1 ,broncho-trachealis brevis4 #d1 ,costal process of sternum4 #e1 ,right and left carotid converging and occupying same sheath at #f4 #g1 ,the heart showing branches of coronary artery4 #h1 ,cervical air-sac4 #i1 ,left brachio-cephalic artery4 #aj1 ,right brachio-cephalic artery4 #aa1 ,trachea4 #ab1 ,inferior larynx4 #ac4 ,subclavian artery4 #ad1 ,carotid trunk4 #ae1 ,internal thoracic artery4 #af ,thyroid gland4 #ag1 ,anterior vena cava4 #ah1 ,auricular appendage4 ,illustration3 ,,fig4 #ba4--,the inferior tracheal region4 #a1 ,bronchialis anticus4 #b1 ,bronchialis posticus4 #c1 ,broncho-trachealis posticus4 #d1 ,broncho-trachealis anticus4 ,action4--,a tensor of the true or inferior larynx4 ,broncho-trachealis ,anticus 7,fig4 #ba1 ,no4 #d74 ,location4--,anterior portion of the inferior extremity of the trachea4 ,origin4--,the anterior branch of the bifurcated tracheo-lateralis4 ,insertion4--,to the anterior extremity of the third half ring of the bronchus of the same side4 ,shape4--,a small fasciculus4 ,relations4--,internally with the trachea1 and externally with the skin and other integument4 ,action4--,a tensor of the inferior larynx4 ,broncho-trachealis ,brevis 7,fig4 #bj1 ,no4 #c74 ,location4--,posterior part of the inferior extremity of the trachea4 ,origin4--,from just beneath the broncho-trachealis anticus muscle4 ,insertion4--,extends obliquely across the inferior larynx and is inserted to the posterior end of the second bronchial ring4 ,shape4--,rather short1 strong1 straight1 subcylindrical4 ,relations4--,internally with the trachea1 and laterally with the broncho-trachealis posticus4 ,action4--,a tensor of the inferior larynx4 ,bronchialis ,posticus 7,fig4 #ba1 ,no4 #b74 ,location4--,supero-lateral side of the anterior end of the bronchi4 ,origin4--,from the lateral inferior margin of the last tracheal ring4 ,insertion4--,passing obliquely across the larynx it inserts to the posterior extremity of the second half ring of the bronchus4 ,shape4--,small1 thick1 spindle-shaped4 ,relations4--,internally with the trachea1 inferiorly with the bronchialis anticus1 and superiorly with the broncho-trachealis brevis4 ,action4--,a tensor of the larynx4 ,bronchialis ,anticus 7,fig4 #ba1 ,no4 #a74 ,location4--,inferior to the former muscle4 ,origin4--,from the last ring of the trachea4 ,insertion4--,the fibers pass obliquely forward and become inserted to the rim of the arytenoid cartilage of the inferior larynx1 and the anterior extremities of the first and second half rings of the bronchus4 ,shape4--,thick1 spindle-shaped2 about twice the size of the bronchialis posticus4 ,relations4--,it is crossed at its origin by the broncho-trachealis anticus and is related internally with the bronchus and end of the trachea4 ,action4--,a tensor of the larynx4 ,sterno-trachealis 7,fig4 #bj1 ,no4 #a74 ,location4--,the inferior region of the trachea above the above-named muscles4 ,origin4--,from the side of the trachea beneath the posterior border of the broncho-trachealis anticus4 ,insertion4--,passes downward and backward across the cavity of the chest and is inserted to the inner part of the costal process of the sternum4 ,shape4--,a delicate cord of fibers4 ,relations4--,internally with the broncho-trachealis muscles4 ,action4--,a relaxor of the larynx1 and hence1 of the tympanic membrane4 ,,the ,,sternal ,,group ,triangularis ,sterni4 ,location4--,in the floor of the thoracic cavity4 ,origin4--,from the entire superior margin of the summits of the costal processes4 ,insertion4--,the fibers extend upward and backward1 dividing into four digitations which cover the inner surface of the three principal sternal ribs1 and are inserted to the first four as high as their articulations with the vertebral ribs4 ,shape4--,flat and somewhat triangular4 ,relations4--,interiorly with the floor of the thoracic cavity4 ,action4--,a powerful muscle of expiration4 ,in contracting1 lessens the cubic content of the thorax4 ,the ,diaphragm 7,fig4 #dg1 ,no4 #aj2 ,fig4 #cc1 ,no4 #i74 ,description4--,the diaphragm in the domestic fowl is rudimentary4 ,it consists of a thin semi-transparent membrane1 situated between and separating the thoracic and the abdominal cavities4 ,it readily conforms to the various organs pressing upon it from each side4 ,on each side are three rudimentary muscles which extend from the vertebral heads of the second1 the third1 and the fourth sternal ribs4 ,the fibers of these muscles spread out in fan-like upon the diaphragm1 and are seen just above the digitations of the triangularis sterni4 ,,the ,,abdominal ,,muscles ,obliquus abdominis externus ,obliquus abdominis internus ,rectus abdominis ,transversalis abdominis ,obliquus ,abdominis ,externus 7,fig4 #bb1 ,no4 #a74 ,location4--,the outermost muscle of the lateral abdominal wall4 ,attachments4--,by a delicate aponeurotic membrane1 from the sides of all the true dorsal ribs1 from the posterior border of the last vertebral rib and the adjoining margins of the pelvis1 and from the entire posterior surface of the inferior border of the post-pubic element of the pelvis2 by aponeurosis1 blending with the fascia toward the root of the tail and lower part of the abdomen2 and by aponeurosis to the sides of the sternum1 to the under part of the pectoralis major muscle1 and to the zyphoid prolongation4 ,also by aponeurosis it meets its fellow from the opposite side1 at the linea alba4 ,illustration3 ,,fig4 #bb4--,the abdominal muscles of a hen4 ,right side4 #a1 ,obliquus abdominis externus4 #b1 ,obliquus abdominis internus4 #c1 ,peritoneum covering intestines4 #d1 ,peritoneum covering the gizzard4 #e1 ,the lungs 7note how small they are from a relative standpoint74 #f1 ,the great sciatic or ischiadic nerve4 #g1 ,lumbar nerves4 #h1 ,kidney4 #i1 ,brachial plexus4 #aj1 ,pericardium of the base of the heart4 #aa1 ,anterior vena cava4 #ab1 ,oil gland4 #ac1 ,showing a sacculation of the abdominal muscles4 ,there is no tunica abdominalis in the fowl4 ,obliquus ,abdominis ,internus 7,fig4 #bb1 ,no4 #b74 ,location4--,just internal with regard to the external oblique4 ,attachments4--,by aponeurosis1 from the posterior third of the post-pubic element of the pelvis2 by muscular fibers1 from the balance of the bone2 and by a few fibers1 from the iliac border posterior to the acetabulum4 ,anteriorly1 these fibers are inserted to the entire posterior margin of the last vertebral rib1 and into the pleurapophysial head of the last costal rib4 ,rectus ,abdominis 7,fig4 #ac1 ,no4 #aj and ,fig4 #bc1 ,no4 #a74 ,location4--,the inferior median abdominal wall4 ,attachments4--,by aponeurosis1 from the distal extremity of the post-pubic element of the pelvis and from the semitendinous ligament which stretches from one post-pubic tip to the other4 ,attaches anteriorly to the zyphoid margin of the sternum1 and passes1 by a broad aponeurotic membrane1 over the outer surface of the thoracic wall beneath the external oblique4 ,transversalis ,abdominis 7,fig4 #be1 ,no4 ,h1 #a74 ,location4--,infero-lateral portion of the abdominal wall4 ,attachments4--,by a thin1 tendinous attachment from the entire post-pubic and iliac margins of the pelvis and from the interpubic ligament4 ,its fibers cross the abdomen between the peritoneum1 the rectum1 and the internal oblique4 ,it is inserted over the entire pleural part of the last two vertebral ribs1 the intercostal muscles between them1 and the same surface of the hemapophyses connected below4 ,inserts into the linea alba4 ,action4--,the abdominal muscles give support to the abdominal organs1 aid in flexing the spine1 draw the last rib backward1 thus aiding in respiration1 and compress the abdominal organs to aid in defecation and expiration4 ,,the ,,dorso-,,lumbar ,,region ,sacro-lumbalis ,longissimus dorsi ,sacro-lumbalis4 ,location4--,the lateral lumbo-sacral region4 ,origin4--,tendinous from the anterior margin of the ilium1 from the angles of the last two vertebral ribs1 and by tendinous slips1 from the outer ends of the transverse processes of the last three dorsal vertebr4 ,insertion4--,by a few fleshy fibers into the angle of the first dorsal rib and to the corresponding points upon the free cervical ribs1 and by a strong semitendinous insertion into the outer extremity of the diapophysis of the twelfth cervical vertebra4 ,shape4--,a close fitting1 tendo-muscular sheet extending between the anterior margin of the ilium and the root of the neck4 ,relations4--,intimately blended with the longissimus dorsi externally4 ,action4--,assists the longissimus dorsi4 ,longissimus ,dorsi 7,fig4 #bd1 ,no4 #d74 ,location4--,the superior dorso-lumbar region4 ,origin4--,from the inner portion of the anterior margin of the ilium1 and from the various surfaces afforded by its walls and the walls of the ilio-neural canal2 by a series of short and distinct tendons alternately from the anterior and posterior extremities of the summits of the neural spines of all the dorsal vertebr4 ,from the diapophyses of the dorsal vertebr1 from the crests of the neural spines of the last three dorsal vertebr1 from the bodies of the dorsal vertebr1 and from the fascia between them and the sacro-lumbalis2 and also by a tendinous sheet continuous with the origin of the longus colli posticus4 ,insertion4--,by four fasciculi into the free posterior margins of the oblique processes of the eleventh1 the twelfth1 the thirteenth1 and the fourteenth cervical vertebr4 ,shape4--,a large flat sheet4 ,relations4--,laterally1 with the superior spinous processes of the vertebr1 and with the superior surface of the ribs4 ,action4--,singly1 flexes the back laterally2 with its fellow1 aids in elevating the body upward4 ,,the ,,coccygeal ,,muscles ,levator coccygis ,levator caud ,transversus peronei ,depressor caud ,depressor coccygis ,lateralis caud ,lateralis coccygis ,infracoccygis ,levator ,coccygis 7,fig4 #bc1 ,no4 #b74 ,location4--,the superior part of the caudal apparatus4 ,origin4--,from a limited area of the ilium just beyond and to the side of the anterior free caudal vertebr4 ,insertion4--,into the tuberosity of the anterior margin of the pygostyle4 ,shape4--,short1 fleshy4 ,relations4--,superior portion of the coccygeal vertebr4 ,action4--,elevates the tail4 ,levator ,caud 7,fig4 #bc1 ,no4 #d74 ,location4--,supero-lateral side of the tail4 ,origin4--,from the posterior surface of the post-acetabular area of the pelvis1 and from the superior surface of all the coccygeal vertebr except the pygostyle4 ,insertion4--,to the four inner quill butts of the main tail feathers4 ,shape4--,long1 spindle-shaped4 ,relations4--,internally1 with the levator coccygis and externally1 with the lateralis caud4 ,action4--,powerfully elevates the four inner main tail feathers4 ,transversus ,peronei 7,fig4 #bc1 ,no4 #c74 ,location4--,the posterior abdominal region4 ,illustration3 ,,fig4 #bc4--,outer layer of muscles of the tail and thigh1 #a1 ,rectus abdominis4 #b1 ,levator coccygis4 #c1 ,transversalis peronie4 #d1 ,levator caud4 #e1 ,lateralis caud4 #f1 ,depressor caud4 #g1 ,sartorius4 #h and #i1 ,gluteus primus4 #aj1 ,semitendinosus4 #aa1 ,gastrocnemius4 #ab1 ,peroneus longus4 #ac1 ,flexor perforatus indicis secundus pedis4 #ad1 ,flexor perforatus medius secundus pedis4 #ae1 ,lateral ligament of the hock4 ,origin4--,from the entire posterior margin of the ischium1 and from the posterior margin of the post-pubis extending beyond it4 ,insertion4--,becoming aponeurotic1 it passes toward the coccyx and is attached to the entire posterior margin of the ilium4 ,passes to the median line1 meeting its fellow in front of the anus4 ,shape4--,thin1 sheet-like4 ,relations4--,infero-anteriorly with the anus4 ,posteriorly with the edges of the ilium and of the ischium4 ,internally with the depressor caud4 ,action4--,gives support to the viscera in the post-anal region1 and aids in attaching the anus to the structures above4 ,depressor ,caud 7,fig4 #bc1 ,no4 #f74 ,location4--,the infero-lateral side of the tail4 ,origin4--,from the lower half of the posterior border of the ischium1 and from the entire posterior border of the post-pubis beyond4 ,insertion4--,to the quill butts of the three or four outer main tail feathers4 ,shape4--,strong1 conical4 ,relations4--,externally1 with the depressor coccygis4 ,action4--,singly1 pulls the tail downward and outward2 with its fellow1 pulls the tail downward4 ,depressor ,coccygis4 ,location4--,the outermost of the infero-lateral muscles of the tail4 ,origin4--,from the lower half of the posterior margin of the ischium and the anterior three-fourths of the posterior margin of the post-pubic element of the pelvis beyond it4 ,insertion4--,to the thickened rim of the inferior and expanded portion of the pygostyle4 ,shape4--,flat1 triangular4 ,relations4--,internally with the depressor caud4 ,action4--,singly1 pulls the tail downward and to one side2 with its fellow1 pulls the tail downward4 ,lateralis ,caud 7,fig4 #bc1 ,no4 #e74 ,location4--,the lateral side of the tail4 ,origin4--,from the tip of the transverse process of the first free caudal vertebr4 ,insertion4--,to the outer three quill butts of the main tail feathers4 ,shape4--,four fasciculi forming a fleshy belly4 ,relations4--,inferiorly1 with the levator caud and superiorly with the depressor caud4 ,action4--,singly1 pulls the tail downward and outward2 with its fellow1 pulls the tail downward4 ,the outermost fasciculus contracting1 spreads the tail feathers4 ,lateralis ,coccygis 7,fig4 #be1 ,no4 ,e1 #b74 ,location4--,the infero-lateral side of the caudal vertebr4 ,origin4--,from the surface of the posterior end of the ilium and by tendons from the under side of the ends of the first three or four caudal vertebr4 ,insertion4--,to the side of the posterior margin of the expanded portion of the pygostyle4 ,shape4--,subcompressed mass4 ,relations4--,with the transverse processes of the caudal vertebra1 inferiorly4 ,action4--,controls the lateral movements of the tail and its feathers1 and the oblique downward movement4 ,infracoccygis 7,fig4 #be1 ,no4 ,e1 #a74 ,location4--,the extreme inferior portion of the caudal vertebr4 ,origin4--,from the inferior surface of the diapophysis of the last vertebra which anchyloses with the pelvic sacrum1 and from all the free caudal vertebr4 ,insertion4--,into the lower side of the pygostyle4 ,shape4--,flat1 somewhat triangular4 ,relations4--,superiorly1 with the vertebr1 laterally1 with the lateralis coccygis1 and mesially1 with its fellow of the opposite side4 ,action4--,depresses the tail4 ,,the ,,costal ,,region ,latissimus dorsi ,trapezius ,rhomboideus ,serratus magnus anticus ,serratus parvus anticus ,teres et infraspinatus ,intercostales ,levatores costarum ,appendico-costales ,latissimus ,dorsi 7,fig4 #bd1 ,no4 #g74 ,location4--,supero-lateral portion of the dorsal region4 ,origin4--,from two portions1 the anterior slip from the outer edge of the superior margins of the neural spines of the second and the third dorsal vertebr1 and the second portion from a similar point on all the succeeding dorsal vertebr4 ,the second portion is fascia-like in its attachments4 ,insertion4--,the fibers converge toward the humerus and enter between the deltoid the scapular head of the triceps and the remaining heads of this muscle and is inserted to the anconal part of the humerus1 just within in the radial crest4 ,shape4--,thin1 triangular4 ,relations4--,superiorly1 with the skin4 ,the most superficial of the dorsal muscles4 ,action4--,to elevate the humerus and thus flex the shoulder-joint4 ,an expiratory muscle when the wing is fixed4 ,trapezius 7,fig4 #ai1 ,no4 #bj74 ,location4--,in the shoulder region1 just below the longissimus dorsi4 ,origin4--,from the neural spines of the second1 the third1 the fourth1 and the fifth cervical vertebr just below the latissimus dorsi4 ,insertion4--,to the mesian upper border of the scapula4 ,shape4--,a flat oblong layer of fibers4 ,relations4--,the posterior part of the trapezius overlies the anterior part of the rhomboideus4 ,the posterior two-thirds is covered by the latissimus dorsi4 ,the anterior third is superficial4 ,action4--,draws the scapula forward4 ,rhomboideus 7,fig4 #ai1 ,no4 #ai74 ,location4--,supero-posterior scapular region4 ,origin4--,from the neural spines of the first four dorsal vertebr beneath the latissimus dorsi and trapezius muscles4 ,insertion4--,the fibers passing outward and backward attach to the posterior third of the mesial or upper border of the scapula4 ,shape4--,thin1 flat1 delicate4 ,relations4--,superiorly1 by the latissimus dorsi and the trapezius4 ,action4--,to draw the free end of the scapula upward and forward4 ,serratus ,magnus ,anticus 7,fig4 #ac1 ,no4 #af74 ,location4--,the supero-lateral side of the thorax4 ,origin4--,by three strong digitations3 first1 from the outer part of the second true rib just above the base of the epineural appendage2 the other two1 from similar locations on the two succeeding ribs1 just above the origin of the dermo-ulnaris4 ,insertions4--,the first by tendinous attachment to the interpleurapophysial membrane4 ,the rest of the fibers pass upward and slightly forward1 and are inserted to the inferior surface of the apex of the scapula4 ,shape4--,three flat1 strong digitations4 ,relations4--,internally1 with the ribs4 ,action4--,if the scapula is fixed1 it is a muscle of inspiration4 ,serratus ,parvus ,anticus4 ,location4--,the outer and upper surface of the anterior part of the thorax4 ,origin4--,by three digitations from the outer surface of the first three ribs above the origin of the serratus magnus anticus and the thoraco-scapularis4 ,insertion4--,the thin sheet of fibers passes upward and backward1 and is inserted to the inferior margin of the scapula4 ,shape4--,thin1 flat4 ,relations4--,internally1 with the ribs4 ,action4--,if the scapula is fixed1 it is a muscle of respiration4 ,teres et ,infraspinatus 7,fig4 #ac1 ,no4 #aa74 ,location4--,scapular region4 ,origin4--,from the superior surface and outer margin of the posterior two-thirds of the scapula4 ,insertion4--,the fibers pass forward and outward1 and insert to the humerus at the middle of the ulnar margin of the pneumatic fossa1 between the forks of the triceps4 ,shape4 --,flat1 triangular-shaped4 ,relations4--,anteriorly1 with the supraspinatus4 ,internally1 with the ribs4 ,action4--,aids in keeping the humerus in its socket4 ,assists in closing the wing by drawing the humerus to the side of the body4 ,intercostales 7,fig4 #bd1 ,no4 #e74 ,location4--,between the ribs of the upper thoracic region4 ,origin and ,insertion4--,from the anterior border of one rib1 the fibers1 passing obliquely upward and forward1 and the lower portion downward and forward1 are inserted to the posterior border of the rib just in front4 ,shape4--,they are best developed in the anterior portion of the thoracic region and extend down as far as the sternal ribs4 ,relations4--,internally the pleura1 and anteriorly and posteriorly the ribs4 ,action4--,the first rib being rendered fixed by the scalenus medius1 the muscles draw the ribs forward1 thus aiding inspiration4 ,levatores ,costarum 7,fig4 #bd1 ,no4 #b74 ,location4--,supero-lateral portion of the thorax4 ,origin and ,insertion4--,a series of muscles1 the first of which extends from the extremity of the transverse process of the twelfth vertebra1 the fibers passing downward and backward to the anterior free margin of the upper third of the long posterior rib1 and to the external surface close to its margin4 ,the others arise and insert in a similar manner from the ends of the diapophyses of all the dorsal vertebr and attach to each succeeding rib4 ,those in front are best developed4 ,shape4--,thin and triangular4 ,relations4--,external to the intercostales4 ,action4--,aids in respiration4 ,appendico-costales 7,fig4 #bd1 ,no4 #a74 ,location4--,the lateral side of the thorax4 ,origin and ,insertion4--,from the posterior edge of an uncinate process or epineural appendage1 the fibers extending downward and backward to the outer surface of the succeeding rib4 ,shape4--,a series of thin triangular-shaped muscles4 ,relations4--,internally1 with the intercostales4 ,action4--,aids in respiration4 ,,the ,,anterior ,,pectoral ,,group ,tensor patagii longus ,tensor patagii brevis ,tensor ,patagii ,longus 7,fig4 #ae;,c1 ,no4 #a2 ,fig4 #ad1 ,no4 #b74 ,location4--,anterior shoulder region1 in the triangular patagium of the wing4 ,origin4--,by a flat tendon common to it and the tensor patagii brevis from the supero-mesial line of the head of the clavicle4 ,insertion4--,by a long slender tendon extending in the duplicature of the patagium1 with which the fibers blend4 ,passing to the side of the extensor metacarpi radialis longus1 it extends over the end of the radius and is inserted to the os carpi radiale1 and to the fascia which binds down the other tendons on the anterior part of the wrist-joint4 ,shape4--,cone-shaped belly terminating in a long tendon4 ,relations4--,externally1 with the skin2 by its tendon1 with the border of the extensor metacarpi radialis longior4 ,action4--,tenses the soft part in the fold of the wing1 and aids in flexing the forearm4 ,tensor ,patagii ,brevis 7,fig4 #ad1 ,no4 #c74 ,location4--,in the triangular patagium of the wing4 ,origin4--,from the head of the clavicle in common with the preceding4 ,insertion4--,the tendon bifurcates1 one branch blending with the fascia of the extensor metacarpi radialis longior1 the other inserting just below the tubercle on the external condyle of the humerus4 ,shape4--,fleshy2 somewhat broader and longer than the preceding4 ,relations4--,interiorly1 with the preceding4 ,action4--,assists the tensor patagii longus in flexing the forearm4 ,,the ,,pectoral ,,muscles ,pectoralis major ,pectoralis secundus ,pectoralis tertius ,pectoralis ,major 7,fig4 #ac1 ,no4 #e74 ,location4--,on the lateral side of the sternum4 ,origin4--,from the posterior portion of the lateral wing of the sternal body1 from the outer marginal third of the keel of the sternum1 and from the entire outer side of the limb of the furcula or clavicle4 ,insertion4--,the fibers converging form toward the proximal third of the humerus a broad tendon which by its insertion covers the entire palmar part of the pectoral crest4 ,a few of the tendinous fibers pass over the shoulder-joint and blend with the long head of the biceps4 ,near this point it receives the insertion of the dermo-humeralis4 ,relations4--,interiorly1 with the skin2 superiorly1 in the sternal region1 with the pectoralis secundus and the pectoralis tertius4 ,shape4--,fleshy2 largest of the pectorales4 ,action4--,powerfully depresses the humerus4 ,the chief muscle of flight4 ,pectoralis ,secundus 7,fig4 #ac1 ,no4 #i2 ,fig4 #ae1 ,no4 ,a1 #f74 ,location4--,the entire lateral side of the sternum4 ,origin4--,from the anterior sternal extremity of the lower third of the coracoid1 from the keel and sternal wing1 and by a tendon from a membraneous expansion between the coracoid and the clavicular bones and from the lower third of the coracoid4 ,insertion4--,the fibers converge into a tendon1 which passes upward around the coracoid to its posterior through a canal formed by the scapula1 the coracoid1 and the clavicle1 the foramen triosseum 7,fig4 #ae1 ,no4 ,a1 #g74 ,this tendon then passes outward and downward1 and becoming flat1 inserts to the humerus just anterior to the radial crest and nearer to the humeral head than does the pectoralis major4 ,relations4--,internally1 with the breast-bone2 externally1 with the pectoralis major2 and superiorly1 with the pectoralis tertius4 ,shape4--,long1 fusiform1 fleshy4 ,action4--,raises the wing4 ,pectoralis ,tertius 7,fig4 #ac1 ,no4 #f2 ,fig4 #ae1 ,no4 ,a1 #e74 ,location4--,on the antero-lateral side of the sternum4 ,origin4--,from the anterior half of the exterior of the body of the sternum1 from the fascia of the subclavius on the outer border of the costal process1 and from the outer1 lower third of the coracoid process4 ,insertion4--,the fibers pass upward to the outer side of the coracoid1 and becoming tendinous as they reach the humerus1 by a strong flattened tendon insert to the ulnar crest of the humerus on the proximal margin at about a middle point of the pneumatic fossa4 ,relations4--,externally1 with the pectoralis major2 interiorly1 with the pectoralis secundus2 internally1 with the fascia of the subclavius and the sternum4 ,shape4--,fleshy1 fusiform4 ,action4--,assists the pectoralis secundus in elevating the humerus4 ,,muscles ,,of ,,the ,,scapular ,,region ,coraco-humeralis ,scapulo-humeralis ,supraspinatus ,subclavius ,coraco-brachialis ,teres minor ,levator scapul ,thoraco-scapularis ,subscapularis ,coraco-humeralis4 ,location4--,the scapulo-humeral region4 ,origin4--,from the outer side of the head of the coracoid1 supero-laterally to the long head of the biceps4 ,insertion4--,to the palmar part of the head of the humerus just inside of the insertion of the pectoralis major4 ,shape4--,a delicate subcylindrical muscle4 ,relations4--,superior to the head of the humerus4 ,action4--,aids in extending the humerus4 ,scapulo-humeralis 7,fig4 #ad1 ,no4 #aj74 ,location4--,the scapulo-humeral region4 ,origin4--,from the inner side of the neck of the scapula just within the head of the deltoid4 ,insertion4--,passing over the top of the shoulder-joint it is inserted to the palmar part of the humeral head between the insertion of the pectoralis major and the pectoralis secundus4 ,shape4--,narrow1 flat ribbon4 ,relations4--,along the upper margin of the larger portion of the deltoid4 ,action4--,aids in extending the humerus4 ,supraspinatus 7,fig4 #ai1 ,no4 #bb74 ,location4--,scapular region4 ,origin4--,from the superior surface and outer third of the scapula4 ,insertion4--,to the lower border of the pneumatic fossa of the humerus4 ,shape4--,thin1 flat1 triangular4 ,relations4--,externally1 with the trapezius and posteriorly1 with the teres et infraspinatus4 ,action4--,if the scapula is the fixed point it will pull the humerus upward and backward4 ,subclavius4 ,location4--,anterior sternal region4 ,origin4--,from the entire outer surface of the sternal process of the sternum and the adjacent outer surfaces of three or four of the hemapophyses4 ,insertion4--,to the inferior margin of the coracoid bone1 the longer fibers passing over to the fossa in the lower third of the posterior part of the coracoid4 ,shape4--,rather small1 fleshy4 ,relations4--,overlapped by the pectoralis tertius4 ,action4--,pulls the coracoid outward4 ,also aids in keeping the coracoid in place4 ,coraco-brachialis 7,fig4 #ac1 ,no4 #ae74 ,location4--,along the coracoid shaft4 ,origin4--,by a delicate tendon from a small circular point on the postero-mesial part of the shaft of the coracoid immediately above the attachment of the subclavius and the fossa at that point4 ,insertion4--,to the top of the ulnar tuberosity of the humerus4 ,this subcircular space is common to the teres minor and to this muscle4 ,shape4--,long1 fusiform4 ,relations4--,with the shaft of the coracoid between the teres minor and subscapularis4 ,action4--,to depress the wing4 ,teres ,minor 7,fig4 #ac1 ,no4 #ad74 ,location4--,the coraco-scapular region4 ,origin4--,from under the side of the anterior tip of the scapula4 ,insertion4--,passing outward behind the coracoid head and beneath the neck of the scapula1 it is attached by a small tendon to the top of the ulnar tuberosity of the humerus in common with the coraco-brachialis1 with which tendon it fuses4 ,shape4--,small1 chunky4 ,relations4--,anteriorly1 with the tip of the scapula and behind the coracoid head4 ,posteriorly1 with the coraco-brachialis4 ,action4--,aids in the downward stroke of the wing4 ,levator ,scapul4 ,location4--,scapular region4 ,origin4--,by two strong digitations1 one from each of the lateral processes of the first cervical vertebra4 ,insertion4--,to the middle third of the inferior part of the blade of the scapula4 ,shape4--,small and flat4 ,relations4--,inferior to the scapula4 ,action4--,pulls the scapula forward1 and with it the entire shoulder girdle1 which articulates like a hinge-joint at the costo-sternal juncture4 ,thoraco-scapularis4 ,location4--,lateral side of the chest4 ,origin4--,from the outer part of the lower half of the first free rib1 the outer side of the next succeeding rib and its epineural appendage1 and from a similar surface on the next rib4 ,insertion4--,by a broad1 flat tendon which passes between the two divisions of the subscapularis and inserts at a point at the juncture of the anterior and middle third of the outer margin of the scapula4 ,shape4--,broad1 flat4 ,relations4--,internally1 with the ribs and the scapula4 ,action4--,when the scapula is fixed it is a muscle of inspiration4 ,when the ribs are fixed1 it draws the scapula downward4 ,subscapularis4 ,location4--,scapulo-humeral region4 ,origin4--,from the anterior and outer half of the scapula4 ,insertion4--,by a strong and subcylindrical tendon to the top of the ulnar tuberosity of the humerus close to the combined tendons of the coraco-brachialis and teres minor4 ,shape4--,a large and powerful muscle4 ,relations4--,the flat tendon of the thoraco-scapularis divides the posterior portion of the belly into two portions4 ,action4--,a powerful rotary muscle of the head of the humerus2 aids in keeping the humeral head in the glenoid cavity4 ,,the ,,muscles ,,of ,,the ,,brachial ,,region ,biceps ,triceps ,deltoid ,brachialis anticus ,biceps 7,fig4 #ac1 ,no4 #h74 7,synonym4--,biceps brachii47 ,location4--,the anterior brachial region4 ,origin4--,by a broad tendon it covers the top of the shoulder-joint1 dividing into two heads1 giving rise to the long and the short heads4 ,the long is inserted into the outer part of the head of the coracoid just beyond the glenoid cavity2 the short head to the distal angle of the ulnar tuberosity of the humerus4 ,insertion4--,to the ulna just in front of the articular cavity for the trochlear surface of the distal extremity of the humerus4 ,shape4--,large1 subfusiform4 ,relations4--,on one side by the triceps and the other the deltoid and anteriorly partially covered by the patagii muscles4 ,action4--,a powerful flexor of the forearm4 ,deltoid 7,fig4 #ac1 ,no4 #ab2 ,fig4 #ae1 ,no4 #h74 ,location4--,occupying the lateral side of the humerus2 the brachial region4 ,origin4--,divided into two portions1 the long narrow head extends from the clavicular process of the scapula and from the adjacent surface of the same bone4 ,these fibers then extend around the back of the shoulder-joint1 and are joined by the fibers that arise from the entire outer surface of the large os humero-scapulare4 ,these latter fibers are inserted upon an extensive area upon the anconal part of the bone beyond the humeral articular head1 and to almost the entire shaft below it4 ,insertion4--,by a subcylindrical tendon to the proximal side of the tubercle of the external condyle1 and above the insertion of the extensor metacarpi radialis longus4 ,shape4--,large1 fleshy1 with tendinous attachment4 ,relations4--,on one side by the biceps and the other by the triceps also the patagii4 ,action4--,to extend the arm4 ,triceps 7,fig4 #ae1 ,no4 #g74 7,synonym4--,triceps brachii47 ,location4--,the posterior humeral region4 ,origin4--,by three portions3 by the internal and external heads1 and by the long scapular head4 ,the internal and the external heads are blended except at their proximal extremities4 ,each head arises from the anconal surface of the shaft of the humerus4 ,the internal head being located toward the deltoid attachment and the external head into the pneumatic fossa4 ,the long head extends from a circumscribed area just posterior to the glenoid cavity of the scapula4 ,the fibers pass around the shoulder-joint1 beneath the deltoid4 ,insertion4--,the broad tendon passes over the elbow-joint and is inserted to the entire under surface of the olecranon of the ulna4 ,shape4--,long1 large1 fleshy4 ,relations4--,the supraspinatus passes between the internal and the external heads4 ,it is bounded by the biceps and the deltoid4 ,action4--,an extensor of the antibrachial region directly antagonizing the biceps4 ,brachialis ,anticus 7,fig4 #ae1 ,no4 #i2 ,fig4 #ad1 ,no4 #e74 ,location4--,in the flexure of the humerus and the ulna4 ,origin4--,it arises fleshy from a circumscribed area on the inner side of the anconal part of the distal extremity of the humerus4 ,insertion4--,the fibers passing directly over the elbow-joint become inserted to the lateral surface of the proximal end of the ulna close to the margin of the sigmoid cavity4 ,shape4--,small1 fleshy4 ,relations4--,with the joint4 ,action4--,assists in flexing the forearm upon the arm4 ,protects the structures in the anterior part of the elbow-joint4 ,,the ,,muscles ,,of ,,the ,,forearm ,,and ,,the ,,hand ,extensor metacarpi radialis longior ,supinator brevis ,extensor digitorum communis ,pronator brevis ,flexor metacarpi radialis ,extensor ossis metacarpi pollicis ,pronator longus ,extensor indicis longus ,flexor digitorum sublimis ,flexor digitorum profundus ,flexor carpi ulnaris ,flexor carpi ulnaris brevior ,extensor ,metacarpi ,radialis ,longior 7,fig4 #ac1 ,no4 #ag74 ,location4--,superior to the radius4 ,origin4--,by two strong tendinous heads2 the outer from the tubercle of the external condyle of the humerus1 just above the origin of the tendon of the tensor patagii brevis2 the inner and stronger portion from the tubercle found above the oblique trochlear facet of the distal end of the radius4 ,insertion4--,becoming a flat1 broad1 and strong tendon at about the middle of the forearm1 finally becomes inserted to the apex of the anchylosed first metacarpal of the carpo-metacarpus4 ,shape4--,a thick1 fusiform belly1 tendinous at both extremities4 ,relations4--,by the side of the pronator brevis4 ,action4--,raises the hand1 and draws it forward toward the radial margin of the forearm and retains it on the same side4 ,extensor ,digitorum ,communis 7,fig4 #ae1 ,no4 #b74 ,location4--,the upper metacarpal region4 ,origin4--,immediately below the tubercle of the external condyle of the humerus4 ,insertion4--,by a small tendon to the outer side of the base of the pollex1 and at a mid-point upon the anterior rim of the proximal phalanx of the middle finger4 ,shape4--,small spindle-shaped1 becoming tendinous at about the middle of the forearm4 ,relations4--,occupies the middle of the group of muscles on the outer side of the forearm4 ,action4--,an extensor of the digit4 ,supinator ,brevis 7,fig4 #ad1 ,no4 #g74 ,location4--,the superior part of the radius4 ,origin4--,from the external condyle of the humerus below the origin of the tendon of the extensor digitorum communis4 ,insertion4--,to the outer side of the shaft of the radius1 for nearly one-third of its length4 ,shape4--,thin1 slender4 ,relations4--,inferiorly1 with the bone4 ,action4--,a supinator of the radial region1 and antagonistic to the pronators4 ,flexor ,metacarpi ,radialis 7,fig4 #ae1 ,no4 #aj74 ,location4--,the lowest of the group of three muscles on the outer part of the forearm4 ,origin4--,by two tendinous heads1 the longer from the external condyle of the humerus1 and the other just beyond the base of the olecranon4 ,insertion4--,becomes tendinous at about the middle of the shaft of the ulna and inserts to a prominent process on the proximal third of the posterior part of the shaft of the mid-metacarpal4 ,shape4--,fusiform4 ,relations4--,inferiorly1 the anconeus and superiorly1 the extensor digitorum communis4 ,action4--,a powerful flexor of the hand4 ,pronator ,brevis 7,fig4 #ac1 ,no4 #ah74 ,location4--,supero-lateral side of the forearm4 ,origin4--,from just above the internal condyle of the humerus4 ,insertion4--,the tendon passing obliquely across the interosseous space and is inserted to the ulnar side of the shaft of the radius1 just beyond the juncture of the proximal and the middle thirds4 ,shape4--,fusiform4 ,relations4--,superior to the pronator longus4 ,action4--,pronates the forearm1 and flexes the forearm upon the arm4 ,pronator ,longus 7,fig4 #ad1 ,no4 #f74 ,location4--,lateral side of the radio-ulnar region4 ,origin4--,from the middle of the internal condyle of the humerus4 ,insertion4--,to the shaft of the radius just beneath the pronator brevis4 ,shape4--,massive1 ellipsoidal4 ,relations4--,between the pronator brevis and flexor digitorum profundus4 ,action4--,a pronator4 ,extensor ,ossis ,metacarpi ,pollicis 7,fig4 #ac1 ,no4 #bc74 ,location4--,slightly interposed between the ulna and radius4 ,origin4--,immediately in front of the greater sigmoid cavity of the ulna4 ,insertion4--,to the palmar side of the base of the first metacarpal1 in common with the extensor metacarpi radialis longior4 ,shape4--,delicate1 straight4 ,relations4--,superiorly1 the extensor indicis longus1 and inferiorly1 the anconeus and the flexor digitorum profundus4 ,action4--,extends the hand upon the forearm4 ,anconeus 7,fig4 #ae1 ,no4 #d74 ,location4--,between the ulna and the radius4 ,origin4--,by a short1 strong1 subcylindrical tendon from the lower posterior of the external condyle of the humerus4 ,insertion4--,to the latero-radial side of the ulna somewhat beyond its middle4 ,shape4--,fusiform4 ,relations4--,superiorly1 the extensor indicis longus1 and inferiorly1 the ulna4 ,action4--,a flexor of the forearm4 ,extensor ,indicis ,longus 7,fig4 #ac1 ,no4 #bb2 ,fig4 #ae1 ,no4 #ac74 ,location4--,infero-lateral to the radius4 ,origin4--,from about one-half the surface of the proximal portion of the radius4 ,insertion4--,possesses a long tendon which passing over a groove at the distal end of the ulna and receiving muscular fibers at the base of the metacarpus1 extends down the anterior part of the hand and is inclosed in a sheath in front of the superior part of the first phalanx of the index-finger4 ,this tendon is inserted into the anterior upper rim of the distal phalanx4 ,shape4--,small1 thin4 ,relations4--,supero-laterally with the radius4 ,action4--,extensor of the digit4 ,flexor ,digitorum ,sublimis4 ,location4--,the forearm4 ,origin4--,from the internal condyle of the humerus4 ,insertion4--,passing over the wrist1 it is inserted to the middle phalanx of the hand4 ,shape4--,a musculo-tendinous band1 rather delicate and rudimentary4 ,relations4--,closely adhering to the integument that stretches from the internal condyle of the humerus to the wrist4 ,action4--,assists these muscles4 ,a flexor4 ,flexor ,digitorum ,profundus 7,fig4 #ac1 ,no4 #ba74 ,location4--,lateral side of the ulna4 ,origin4--,by two heads from the proximal extremity of the ulna1 between which the brachialis anticus passes4 ,insertion4--,the two bellies uniting are attached to the under side of the shaft of the ulna4 ,it becomes tendinous about the middle of the shaft1 and inserts to the ulnar side of the base of the distal joint of the index-finger4 ,shape4--,a fleshy belly with long tendon4 ,relations4--,inferiorly1 with the flexor carpi ulnaris1 superiorly1 with the pronator brevis4 ,action4--,a flexor of the digit4 ,flexor ,carpi ,ulnaris 7,fig4 #ac1 ,no4 #ai74 ,location4--,inferior part of the forearm4 ,origin4--,by two strong tendons2 one from the side and posterior of the internal condyle of the humerus1 passing through the humero-ulnar pulley at the side of the base of the olecranon process2 the other1 to the posterior of the internal condyle of the humerus4 ,it does not pass through a pulley4 ,insertion4--,a subcylindrical tendon extends back of the ulnare ossicle of the carpus giving off a tendinous slip to the flexor digitorum profundus1 and becomes inserted to the anterior rim of the proximal phalanx of the index digit4 ,it has an attachment at the carpus4 ,shape4--,a strong fleshy belly terminating in a long tendon4 ,relations4--,the outermost inferior muscle of the forearm4 ,action4--,a powerful flexor of the hand upon the forearm4 ,flexor ,carpi ,ulnaris ,brevior 7,fig4 #ac1 ,no4 #bj74 ,location4--,inferior part of the antibrachial region4 ,origin4--,from a broad area on the middle third of the upper side of the shaft of the ulna4 ,insertion4--,near the top of the outer edge of the anchylosed os magnum of the carpo-metacarpus4 ,shape4--,thin1 somewhat flat4 ,relations4--,to the inside of the flexor digitorum profundus4 ,action4--,flexes the hand upon the forearm and rotates the hand toward the body4 ,,other ,,muscles ,,of ,,the ,,digits ,extensor proprius pollicis ,flexor minimi digiti ,abductor minimi digiti ,interosseous palmaris ,flexor brevis pollicis ,flexor minimi digiti brevis ,interosseous dorsalis ,flexor metacarpi brevis ,extensor ,proprius ,pollicis 7,fig4 #ac1 ,no4 #bi;a74 ,location4--,anterior to the radio-carpal joint4 ,origin4--,from the ulnar side of the tendon of the extensor metacarpi radialis longior4 ,insertion4--,to the antero-ulnar side of the pollex4 ,shape4--,small1 spindle-shaped2 tendinous at both attachments4 ,relations4--,inferiorly1 with the proximal and anterior part of the metacarpus4 ,action4--,an extensor of the pollex4 ,flexor ,brevis ,pollicis 7,fig4 #ac1 ,no4 #bh;a74 ,location4--,anterior to the pollex4 ,origin4--,from the shaft of the mid-metacarpal bone1 just below the pollex4 ,insertion4--,distal apex of the pollex4 ,shape4--,short1 small1 fleshy4 ,relations4--,superiorly1 with the inferior part of the pollex4 ,action4--,flexes the pollex4 ,flexor ,minimi ,digiti4 ,location4--,inferior side of the metacarpus4 ,origin4--,from the posterior part of the median metacarpal close to the os carpi ulnare4 ,a few fibers extend to the ulna4 ,insertion4--,into the base of the median phalanx4 ,shape4--,small1 slender1 short4 ,relations4--,superiorly1 with the metacarpal bone4 ,action4--,a flexor of the digit4 ,flexor ,minimi ,digiti ,brevis 7,fig4 #ac1 ,no4 #cj74 ,location4--,inferior to the third1 or small finger4 ,origin4--,from the lower and posterior end of the median metacarpal and from the adjacent tendon of the preceding4 ,insertion4--,inserted to the apex of the small finger4 ,shape4--,small and rather rudimentary4 ,relations4--,inferior to the small finger4 ,action4--,acts as a posterior ligament of this joint4 ,abductor ,minimi ,digiti4 ,location4--,supero-lateral side of the small finger4 ,origin4--,from the proximal extremity of the anterior aspect of the third finger4 ,insertion4--,to the posterior border of the proximal phalanx of the second1 or index-finger at a point just above the tip of the third finger4 ,shape4--,a few muscular fibers with some tendinous material4 ,relations4--,at the base of the median segment of the index-finger and to the side of the third4 ,action4--,antagonizes the powerful flexors on the back of the joint4 ,interosseus ,dorsalis 7,fig4 #ac1 ,no4 #ca74 ,location4--,by the side of the metacarpus4 ,origin4--,from the margin of the shaft of the median metacarpal4 ,insertion4--,to the anterior part of the base of the distal phalanx of the index digit4 ,shape4--,short1 delicate1 with long tendon4 ,relations4--,internally1 the metacarpal bone4 ,action4--,extends the last bone of the middle finger4 ,interosseus ,palmaris 7,fig4 #ac1 ,no4 #cb74 ,location4--,on the opposite side of the bone from the interosseous dorsalis4 ,origin4--,from the shaft of the median metacarpal under the preceding4 ,insertion4--,to the apex of the last joint of the second1 or middle finger4 ,shape4--,small1 delicate1 with long slender tendon4 ,relations4--,beneath the preceding and along the metacarpal bone4 ,action4--,flexes the terminal phalanx4 ,flexor ,metacarpi ,brevis4 ,location4--,to the lateral side of the metacarpal bone4 ,origin4--,from the outer side of the distal extremity of the ulna4 ,insertion4--,to the base1 in front1 and on the ulnar side of the proximal phalanx of the index digit4 ,shape4--,delicate1 with long slender tendon4 ,relations4--,on the lateral side of the ulna and the metacarpal bone4 ,action4--,flexes the metacarpus4 ,,muscles ,,of ,,the ,,posterior ,,limb ,sartorius ,gluteus medius ,extensor femoris ,biceps flexor cruris ,semitendinosus accessorius ,femoro-caudal ,obturator internus ,abductor longus ,gluteus primus ,gluteus minimus ,vastus internus ,semitendinosus ,semimembranosus ,obturator externus ,gemellus ,adductor magnus ,sartorius 7,fig4 #bc1 ,no4 #g74 ,location4--,extreme anterior portion of the thigh4 ,origin4--,from the outer two-thirds of the superior surface of the raised emarginations of the anterior border of the ilium1 and by fascia from the neural spines of the fourth dorsal vertebra4 ,insertion4--,obliquely by a semitendinous fascia to the inner edge of the ligamentum patella1 and to the inner and adjacent border of the anterior half of the summit of the tibia4 ,shape4--,large1 fleshy4 ,relations4--,posteriorly1 with the gluteus primus and the vasti4 ,action4--,extends the leg1 flexes and adducts the thigh4 ,gluteus ,primus 7,fig4 #bc1 ,no4 #h and #i74 ,location4--,the outer flat massive muscle of the thigh4 ,origin4--,by a thin fascia from nearly the entire length of the supero-internal margin of the pre-acetabular portion of the ilium1 above the antitrochanter1 and from the entire length of the post-acetabular ridge4 ,insertion4--,near the patella it joins the tendon of the extensor femoris1 and by aponeurosis spreads over the knee and is inserted to the crest of the upper border of the tibia1 the patella being incorporated in its aponeurotic ligament4 ,shape4--,triangular in shape1 it is aponeurotic anteriorly and more fleshy posteriorly4 ,relations4--,anteriorly1 covers over the posterior portion of the sartorius and the body of the gluteus medius2 posteriorly1 bordered by the semitendinosus and the biceps4 ,action4--,abducts the thigh4 ,gluteus ,medius 7,fig4 #bd1 ,no4 #aa74 ,location4--,supero-anterior part of the ilium under the gluteus primus4 ,origin4--,from the entire supero-internal margin of the pre-acetabular surface of the ilium and the concave surface on the adjacent bone4 ,insertion4--,by a strong tendon which passes over a bursa on the anterior rim of the trochanter and is inserted obliquely to this trochanter4 ,shape4--,a fleshy muscle filling the concavity of the pre-acetabular division of the ilium4 ,relations4--,superiorly1 with the gluteus primus2 inferiorly1 with the gluteus minimus4 ,action4--,abducts and pulls the femur forward4 ,gluteus ,minimus 7,fig4 #bd1 ,no4 #ab74 7,synonym4--,gluteus profundus47 ,location4--,beneath the medius and the smaller of the two4 ,origin4--,to the anterior margin of the outer border of the ilium1 and from the supero-external surface of the last rib4 ,insertion4--,the fibers extending downward and backward and outward become tendinous and are inserted below the trochanter of the outer part of the upper third of the femur4 ,shape4--,small1 fleshy4 ,relations4--,inferiorly1 with the bone and superiorly1 with the gluteus medius4 ,action4--,abducts and pulls the thigh forward4 ,extensor ,femoris 7,fig4 #bd1 ,no4 #ae74 ,location4--,anterior femoral region4 ,it is divided into two parts3 the vastus externus and the crureus4 ,origin4--,the vastus extemus 7,fig4 #bd1 ,no4 #ad7 arises tendinous from the base of the trochanter of the outer part of the femur and from this point down the bone approximately to the condyle4 ,the crureus 7,fig4 #bd1 ,no4 #ac7 originates by a tendon from the anterior upper prominent rim of the trochanter1 from this point extending down the antero-external part of the shaft of the femur4 ,insertion4--,merges with the gluteus primus1 and1 by a fascia-like arrangement1 spreads over the front of the knee-joint inserts to the patella and is also inserted into the crest of the tibia4 ,shape4--,large1 fleshy4 ,relations4--,posteriorly1 with the femur and anteriorly1 with the sartorius4 ,action4--,extends strongly the leg upon the thigh4 ,vastus ,internus 7,fig4 #af1 ,no4 #c74 ,location4--,internal and lateral side of the femur4 ,origin4--,from the postero-internal part of the shaft of the femur just below the head1 and in a straight line extending down the femur4 ,insertion4--,by a broad tendon along the thickened inner border of the summit of the tibia4 ,shape4--,thick1 long4 ,relations4--,anteriorly1 with the bone2 surrounded by the other crural muscles4 ,action4--,extends the leg upon the knee2 a powerful assistant of the extensor femoris4 ,biceps ,flexor ,cruris 7,fig4 #ag1 ,no4 ,d1 #a74 ,location4--,posterior tibial region4 ,origin4--,by a tendinous fascia from the post-acetabular ridge1 extending between the antitrochanter and the anterior point of the insertion of the semitendinosus4 ,insertion4--,to the tuberosity on the external part of the shaft of the fibula a short distance below the head4 ,shape4--,large1 rather cone-shaped with base directed upward4 ,relations4--,anteriorly1 with the vastus externus2 posteriorly1 with the semitendinosus4 ,the inferior tendinous portion passes through a tendinous sling or pulley called the biceps band4 ,action4--,flexes the leg upon the thigh4 ,semitendinosus 7,fig4 #bc1 ,no4 #aj74 ,location4--,posterior femoral region4 ,origin4--,by a tough1 strong fascia from the surface of the caudal muscles and from the posterior third of the post-acetabular ridge4 ,insertion4--,the fibers pass downward and forward1 and insert to the tendinous raphe along the posterior margin of the semitendinosus accessorius2 lower down it merges with the median fascia of the inner head of the gastrocnemius4 ,shape4--,fleshy1 broad1 flat and long4 ,relations4--,internally1 with the semimembranosus and anteriorly1 with the biceps flexor cruris4 ,action4--,flexes the leg4 ,semitendinosus ,accessorius4 ,location4--,posterior femoral region4 ,origin4--,from an oblique line just above the condyle1 on the posterior of the shaft of the femur4 ,insertion4--,its fibers1 passing upward and backward1 attach themselves to the tendinous raphe common to this muscle and the semitendinosus1 and are finally inserted to the inner side of the shaft of the tibia4 ,shape4--,flat1 oblong4 ,relations4--,posteriorly to the shaft of the femur1 and externally to the long adductors of the thigh4 ,action4--,aids the preceding in flexing the leg4 ,semimembranosus 7,fig4 #bd1 ,no4 #ag74 ,location4--,postero-internal to the semitendinosus4 ,origin4--,from the outer surface of the ischium1 beginning at the lower margin of its notch on the posterior pelvic border1 extends on a curved line on the adjacent surface beyond4 ,insertion4--,the fibers1 passing downward and forward1 insert by a broad1 thin tendon to the shaft of the tibia a short distance below the head and on a line parallel to the long axis of the tibia4 ,shape4--,long1 narrow1 ribbon-shaped4 ,relations4--,lies adjacent to the semitendinosus and in the same plane4 ,action4--,directly flexes the leg4 ,femoro-caudal 7,fig4 #bd1 ,no4 #h74 ,location4--,infero-lateral to the caudal and post-femoral region4 ,origin4--,by a delicate tendon from the base of the pygostyle4 ,insertion4--,by a thin1 flat tendon upon the outer part of the shaft of the femur below the trochanter and at about the juncture of the upper and middle third of the bone4 ,illustration3 ,,fig4 #bd4--,second layer of muscles of the thigh of a cock4 ,outside view4 #a1 ,appendico-costales4 #b1 ,levatores costarum4 #c1 ,sacro-lumbalis4 #d1 ,longissimus dorsi4 #e1 ,intercostales4 #f1 ,longissimus dorsi4 #g1 ,latissimus dorsi4 #h1 ,femoro-caudal4 #i1 ,edge of obturator externus4 #aa1 ,gluteus medius4 #ab1 ,gluteus minimus4 #ac1 ,crureus4 #ad1 ,vastus externus4 #ae1 ,extensor femoris4 #af1 ,biceps flexor cruris4 #ag1 ,semimembranosus4 #ah1 ,adductor magnus4 #ai1 ,adductor longus4 #bj1 ,external abdominal oblique4 #ba1 ,depressor coccygis4 #bb1 ,tibialis anticus4 #bc1 ,tibialis posticus4 #bd1 ,flexor perforans digitorum profundus4 #be1 ,flexor perforatus medius secundus pedis4 #bf1 ,flexor longus hallucis4 ,shape4--,long1 narrow1 spindle-shaped1 flattened from side to side4 ,relations4--,interiorly to the obturator externus1 and along the upper border of the long adductors of the thigh and the semimembranosus4 ,action4--,pulls the tail down and to one side4 ,obturator ,externus 7,fig4 #bd1 ,no4 #i74 ,location4--,external posterolateral side of the pelvis4 ,origin4--,from the posterior half of the periphery of the ischiatic foramen and the concavity found on the external surface of the lateral part of the pelvis4 ,insertion4--,the fibers pass across to the femur and are inserted by a broad1 flat tendon to the shaft of the femur just below the trochanter4 ,shape4--,thick1 fleshy4 ,relations4--,lies just above the femoro-caudal muscle1 the sciatic nerve and femoral artery pass over and external to its tendon4 ,action4--,pulls the head of the femur backward4 ,obturator ,internus 7,fig4 #af1 ,no4 ,e1 #a74 ,location4--,occupies the space between the ischium and the pubis4 ,origin4--,from the ventral surface of the ischium1 including the posterior border1 from the inner line of the corresponding post-pubis1 and from the membrane covering the space between these two bones4 ,insertion4--,becoming dense1 subcylindrical1 and strong1 it passes through the obturator foramen and is inserted to the outer part of the trochanter of the femur1 in common with the gemellus and opposite to the insertion of the gluteus medius4 ,shape4--,subtriangular and flat with a central tendon2 bipenniform4 ,relations4--,outside the pelvis the tendon lies upon the gemellus and is external to it4 ,fills the obturator foramen and the space between the ischium and the pubis4 ,action4--,acts as a posterior stay to the head of the femur4 ,gemellus 7,fig4 #be1 ,no4 #e74 ,location4--,posterior to the head of the femur4 ,origin4--,from the fossa between the acetabulum and the obturator foramen1 and on the outer side of the pelvis4 ,insertion4--,its fibers are attached by fascia to the tendon of the obturator internus1 and pass directly to the trochanter of the femur where they insert in common with that of the obturator internus4 ,shape4--,strong1 thick1 chunky4 ,relations4--,postero-external to the head of the femur4 ,action4--,like the two preceding1 when the head of the femur is fixed1 it pulls the pelvis forward and steadies it on the head of the femur4 ,adductor ,longus 7,fig4 #bd1 ,no4 #ai74 ,location4--,in the posterior femoral region4 ,origin4--,from a line on the lateral part of the pelvis4 ,insertion4--,the fibers1 passing downward and forward1 are inserted on a longitudinal line along the posterior part of the shaft of the femur4 ,shape4--,broad1 flat1 fleshy4 ,relations4--,posteriorly to the femur1 and anteriorly to the adductor magnus4 ,action4--,adducts the thigh4 ,adductor ,magnus 7,fig4 #bd1 ,no4 #ah74 ,location4--,posterior femoral region4 ,origin4--,from the fine constituting the lower boundary of the ischiatic fossa on the outer lateral part of the pelvis4 ,insertion4--,the fibers pass downward and are inserted to the superior curve of the internal femoral condyle4 ,the internal head of the gastrocnemius blends with this muscle just above its attachment4 ,shape4--,long1 narrow4 ,relations4--,posteriorly to the adductor magnus and anteriorly to the semimembranosus4 ,action4--,strongly adducts the thigh4 ,,the ,,tibial ,,group ,gastrocnemius ,peroneus longus ,extensor longus digitorum ,tibialis posticus ,flexor longus hallucis ,flexor perforatus annularis primus pedis ,flexor perforatus medius secundus pedis ,flexor perforans digitorum profundus ,soleus ,tibialis anticus ,extensor hallucis brevis ,flexor perforatus indicis secundus pedis ,flexor perforatus medius primus pedis ,flexor perforatus indicis primus pedis ,extensor brevis digitorum ,flexor hallucis brevis ,extensor annularis brevis ,gastrocnemius 7,fig4 #bc1 ,no4 #aa74 ,location4--,posterior tibial region4 ,origin4--,there are three heads3 the internal1 the external1 and the tibial4 ,the external head extends by a short1 flattened1 strong tendon from the postero-external part of the external condyle of the femur2 the internal head extends from the outer surface of the inner condyle of the femur2 and the tibial head extends from the entire inner rim of the tibial summit and from the free edge of the adjacent crest4 ,insertion4--,at the lower fourth of the tibial shaft1 terminates in a broad1 flat tendon which passes over the shallow1 longitudinal groove of the tibial cartilage1 and1 crossing the tibio-tarsal joint1 is inserted to the posterior surface of the hypotarsus of the metatarsal bone1 and finally1 below this point1 merges into the podothecal sheath confining the flexor tendons4 ,shape4--,large1 fleshy1 somewhat cone-shaped with the base upward4 ,relations4--,the posterior fleshy muscle of the post-tibial region located anterior to the soleus4 ,action4--,extends the metatarsus on the tibia4 ,soleus 7,fig4 #be1 ,no4 ,g1 #a74 ,location4--,the posterior tibial region4 ,origin4--,from the posterior part of the head of the tibia4 ,insertion4--,by a long slender tendon to the proximal end and toward the inner angle of the tibial cartilage1 some of the fibers passing to the tendon of the gastrocnemius4 ,shape4--,small1 flattened4 ,relations4--,anteriorly1 with the flexor perforans digitorum profundus and posteriorly1 with the gastrocnemius4 ,action4--,similar to that of the gastrocnemius4 ,peroneus ,longus 7,fig4 #bc1 ,no4 #ab74 ,location4--,antero-lateral tibial region4 ,origin4--,from the raised crest in front of the head of the tibia1 and from the fascia that covers the outer side of the knee-joint4 ,insertion4--,the fibers1 passing downward1 then downward and outward1 terminate in a small tendon at the lower third of the tibia4 ,this tendon bifurcates just above the tibial condyles at the outer part of the limb1 the shorter and stronger attaches to the fibrous fascia covering the tibial cartilage1 the other merging with the tendon of the flexor perforatus medius primus pedis about #a centimeter below the hypotarsus of the tarso-metatarsus4 ,relations4--,covers over all the muscles of the anterior tibial region4 ,shape4--,a broad muscular sheet4 ,action4--,assists the flexor perforatus medius primus pedis4 ,tibialis ,anticus 7,fig4 #bd1 ,no4 #bb74 ,location4--,in the anterior tibial region4 ,origin4--,the muscular belly may be easily divided into two parts4 ,the inner head extends from the head of the tibia immediately beneath the peroneus longus4 ,the outer head arises by a strong tendon from a depression on the antero-inferior ridge of the outer condyle of the femur4 ,insertion4--,the tendon passing through the fibrous ligamentous loop just above the tibial condyles1 inserts to a tubercle on the shaft just below the head of the tarso-metatarsus4 ,shape4--,large1 fusiform4 ,relations4--,beneath the peroneus longus4 ,action4--,flexes the metatarsus upon the tibia4 ,extensor ,longus ,digitorum 7,fig4 #be1 ,no4 ,g1 #f74 ,location4--,anterior tibial region4 ,origin4--,from the inferior portion of the crest and a portion of the shaft of the fibula4 ,insertion4--,it becomes tendinous at the lower third of the bone1 passing under the bony ridge just above the condyle in front1 and over the ankle-joint4 ,it is bound down by firm fascia1 and at the trochlea of the basal toe joints1 divides into three small tendinous slips4 ,these pass over the superior part of the second1 the third1 and the fourth toes1 bifurcating in their course1 and are inserted to the distal ones4 ,shape4--,long1 penniform1 with a long1 slender tendon4 ,relations4--,immediately below the tibialis anticus4 ,action4--,extends the digits as their long extensor4 ,extensor ,hallucis ,brevis 7,fig4 #be1 ,no4 ,g1 #d74 ,location4--,the anterior metatarsal region1 along the antero-internal edge4 ,origin4--,from just below the summit of the antero-internal part of the head of the tarso-metatarsus1 and from the adjacent shaft below1 and from the tendon of the tibialis anticus4 ,insertion4--,into the process at the superior part of the bone of the bony claw of the hallux4 ,shape4--,slender1 thin in diameter1 with a long1 slender tendon4 ,relations4--,superiorly1 with the antero-internal edge of the metatarsus and interiorly1 its tendon with the top of the hallux4 ,action4--,extends the hallux4 ,extensor ,brevis ,digitorum4 ,location4--,on the anterior surface of the metatarsus4 ,illustration3 ,,fig4 #be4--;,inner layer of muscles of the thigh of a hen4 ,outside view4 ,a4 ,pad of fibrocartilage or meniscus of femoro-tibial articulation4 #a1 ,inner semi-lunar fibrocartilage4 #b1 ,external semi-lunar cartilage4 #c1 ,anterior border4 ,b4 ,tarsal meniscus or pad of fibrocartilage4 ,c4 ,articular surface of the tarsal joint4 #a1 ,posterior ligamentum cruciatum genu4 #b1 ,femoral tendinous insertion of tibialis anticus4 #c1 ,ligamentum tibio-fibulare4 #d1 ,ligamentum interosseum4 #e1 ,ligamentum transversum of the meniscus4 #f1 ,anterior ligamentum cruciatum genu4 ,d4 #a1 ,tibia4 #b1 ,fibula4 #c1 ,femur4 #d1 ,external ligamentum laterale genu4 ,e4 ,inferior surface of the tail of a hen4 #a1 ,infracoccygis4 #b1 ,lateralis coccygis4 ,f4 ,outside pelvic view4 #a1 ,obturator ligament4 #b1 ,tendon of the obturator internus4 #c1 ,ligamentum oblongum4 #d1 ,ligamentum capsulare4 #e1 ,gemellus4 ,g4 ,outside view of leg of a cock4 #a1 ,soleus4 #b1 ,flexor longus hallucis4 #c1 ,flexor perforans digitorum profundus4 #d1 ,extensor brevis hallucis4 #e1 ,extensor brevis annularis4 #f1 ,extensor longus digitorum4 #g1 ,tendon of the tibialis posticus4 ,h4 #a1 ,transversalis abdominalis4 #b1 ,cotyloid cavity4 ,origin4--,by a small fleshy belly to the anterior part of the proximal end of the metatarsus4 ,insertion4--,it becomes tendinous about the middle third of the metatarsus4 ,extending down the anterior face of the metatarsus it is inserted to the inner tubercle of the base of the first phalanx of the outer or fourth toe4 ,shape4--,long1 slender4 ,relations4--,posteriorly with the metatarsus4 ,action4--,pulls the fourth toe upward and inward4 ,flexor ,hallucis ,brevis4 ,location4--,postero-internal side of the metatarsus4 ,origin4--,side and lower margin of the inner aspect of the hypotarsus of the tarso-metatarsus and from the shaft of this bone immediately below it4 ,insertion4--,winds round inner side of basal joint of the hallux and is inserted on its under side4 ,shape4--,small flat muscle gradually tapering into a tendon4 ,relations4--,posteriorly with the metatarsus4 ,action4--,to flex the hallux4 ,extensor ,annularis ,brevis4 ,location4--,on postero-external side of metatarsus4 ,origin4--,external aspect of the hypotarsus and the shaft below4 ,insertion4--,supero-external part of the basal phalanx of the fourth toe4 ,shape4--,small flat muscle4 ,relations4--,posteriorly with the metatarsus4 ,action4--,extensor of the fourth toe4 ,tibialis ,posticus 7,fig4 #bd1 ,no4 #bc74 ,location4--,in the posterior tibial region4 ,origin4--,from the whole shaft of the fibula below the insertion of the biceps flexor cruris1 and from the shaft of the tibia a short distance below this insertion4 ,also from the interosseous membrane1 and the adjacent surface of the tibial shaft4 ,insertion4--,passing in front of the external malleolus1 crossing the ankle-joint1 finally inserted into the outer edge of the summit of the tarso-metatarsal bone4 ,shape4--,long1 subcylindrical4 ,relations4--,medially1 with the flexor perforans digitorum pedis2 superiorly1 with the postero-external portion of the tibia4 ,action4--,extends the metatarsus upon the tibia4 ,flexor ,perforatus ,indicis ,secundus ,pedis 7,fig4 #ag1 ,no4 #e74 ,location4--,the posterior tibial region4 ,origin4--,from the external surface of the outer condyle of the femur1 just below the head of the gastrocnemius4 ,insertion4--,passing in an oblique manner along posterior to the tibia1 extends through the superficial part of the tibial cartilage to the outer side of the leg2 then crossing the tibio-tarsal joint1 it passes through a special canal of the hypotarsus1 down the back of the tarso-metatarsus1 under the annular ligament of the sole of the foot and a cartilaginous structure below this ligament1 over the trochlea1 and is inserted to the middle shaft of the second phalanx of the second toe4 ,shape4--,thin1 flat1 broadly spindle-shaped4 ,relations4--,posteriorly1 with the flexor perforatus medius secundus pedis1 and anteriorly1 with the flexor perforatus annularis primus pedis4 ,action4--,flexes the toes4 ,flexor ,longus ,hallucis 7,fig4 #ag1 ,no4 #g2 ,fig4 #be1 ,no4 #b74 ,location4--,the posterior tibial region4 ,origin4--,by two tendinous heads3 one from the posterior part of the femur1 just below the two condyles2 the other from the outer part of the external condyle of the femur4 ,the deep flexor passes between these two heads4 ,insertion4--,becoming tendinous at the lower third of the leg1 passes beneath the superficial flexors in a special canal on the outer side of the tibial cartilage1 and extends through the large canal of the hypotarsus 7,fig4 #ab1 ,no4 ,f1 #e7 next to the shaft1 then down to the apex of the accessory metacarpal bone4 ,it is inserted to the tubercle on the inferior proximal end of the ungual phalanx4 ,shape4--,large1 fusiform4 ,relations4--,with the exterior of the deep flexors4 ,action4--,flexes the hallux as its long flexor4 ,flexor ,perforatus ,annularis ,primus ,pedis 7,fig4 #ag1 ,nos4 ,d1 #h and ,c1 #f74 ,location4--,the posterior tibial region4 ,origin4--,from the inner side of the belly of the flexor longus hallucis4 ,insertion4--,becoming tendinous at the lower third of the tibia1 passes a little to the outer side and through the tibial cartilage1 then over the ankle-joint and through the hypotarsal canal 7,fig4 #ab1 ,no4 #e7 to the under side of the outer toe1 where it forms a sheath through which the deep flexors extend4 ,it gives off on either side a tendinous slip which attaches to the basal phalanx4 ,shape4--,long1 slender1 compressed laterally4 ,relations4--,internally1 with the flexor perforatus indicis secundus pedis1 and externally1 with the flexor longus hallucis4 ,action4--,flexes the toes as their long flexor4 ,a second flexor of the outer toe4 ,flexor ,perforatus ,medius ,secundus ,pedis 7,fig4 #ag1 ,no4 #i74 ,location4--,the posterior tibial region4 ,origin4--,from a strong fascia that merges with the knee-joint1 and by a tendon from the external condyle of the femur in common with the tendon of the flexor perforatus indicis secundus pedis4 ,insertion4--,continued as a flattened tendon extending from the lower third of the leg1 passing obliquely through the tibial cartilage and then through the interno-posterior canal of the hypotarsus1 7,fig4 #ab1 ,no4 ,f1 #e7 inserted to the second joint of the middle toe4 ,shape4--,long1 fusiform4 ,relations4--,with the shaft of the fibula1 which it covers4 ,action4--,flexes the middle toe4 ,flexor ,perforatus ,medius ,primus ,pedis 7,fig4 #ag1 ,no4 #b74 ,location4--,posterior tibial region4 ,origin4--,from the inner side of the muscular portion of the flexor perforatus annularis primus pedis4 ,insertion4--,terminating in a flattened tendon1 passes through the tibial cartilage and hypotarsus1 and then extends along the shaft of the basal joint of the third toe1 and1 dividing into two slips1 inserts to either side of its shaft4 ,shape4--,long1 rather small4 ,relations4--,with the flexor perforatus annularis primus pedis on the inner side4 ,action4--,flexes the third toe4 ,flexor ,perforatus ,indicis ,primus ,pedis 7,fig4 #ag1 ,no4 #d74 ,location4--,the posterior tibial region4 ,origin4--,from a thin1 broad tendon1 on the external condyle of the femur1 in common with the flexor perforatus medius secundus pedis4 ,insertion4--,becoming tendinous1 passes through the tibial cartilage and the hypotarsus of the metatarsus 7,fig4 #af1 ,a7 and inserts to the sides of the basal joint of the second toe4 ,shape4--,long1 slender1 fusiform2 somewhat flattened laterally4 ,relations4--,with the flexor perforatus medius secundis pedis1 posteriorly4 ,action4--,a flexor of the toes4 ,flexor ,perforans ,digitorum ,profundus 7,fig4 #bd1 ,no4 #bd and ,fig4 #be1 ,no4 ,g1 #c74 ,location4--,the posterior tibial region4 ,origin4--,from the posterior part of the external condyle of the femur1 from the posterior part of the tibia just below the summit1 and from a point near the origin of the soleus4 ,insertion4--,its heavy flattened tendon passes through the tibial cartilage1 this tendon dividing1 the branches pass along the under side of the toes1 perforating the outer tendons and become inserted to the proximal tubercle at the base of the under side of the ungual phalanxes of the second1 third1 and fourth toes4 ,shape4--,long1 fleshy1 with a long tendon4 ,relations4--,closely with the tibial bone2 the deepest of all the flexors4 ,action4--,flexes the digits4 ,,the ,,muscles ,,of ,,the ,,eye ,orbicularis palpebrarum ,depressor palpebr inferioris ,pyramidalis nictitans ,obliquus inferior ,rectus inferior ,levator palpebr superioris ,quadratus nictitans ,obliquus superior ,rectus superior ,rectus externus ,rectus internus ,orbicularis ,palpebrarum 7,fig4 #g1 ,no4 #cj74 7,synonym4--,orbicularis oculi47 ,location4--,upon the lacrimal and maxillary bones4 ,origin4--,from the lacrimal and maxillary bones and the ciliary margin4 ,insertion4--,to the lower free edge of the tarsal cartilage4 ,shape4--,thin1 delicate layer of fibers4 ,relations4--,externally1 with the skin2 internally1 with the lacrimal and the maxillary bones4 ,action4--,aids in closing the eye4 ,levator ,palpebr ,superioris 7,fig4 #g1 ,no4 #bd74 ,location4--,along the superior roof of the orbit4 ,origin4--,along a longitudinal line found near the middle of the roof of the orbit4 ,insertion4--,to the ciliary margin of the upper lid1 near the outer canthus4 ,shape4--,thin1 delicate layer4 ,relations4--,superiorly1 with the bony wall1 and inferiorly1 with the eyeball4 ,action4--,raises the superior eyelid4 ,depressor ,palpebr ,inferioris 7,fig4 #g1 ,no4 #bi74 7,synonym4--,malaris47 ,location4--,along the inferior border of the eye4 ,origin4--,from the inferior border of the interorbital foramen4 ,insertion4--,to the lower lid4 ,shape4--,thin1 flat1 delicate4 ,relations4--,superiorly1 with the eyeball2 inferiorly1 with the inferior orbital wall4 ,action4--,pulls the lower lid down4 ,quadratus ,nictitans 7,fig4 #bf1 ,no4 ,b1 #g74 ,location4--,above the eyeball along the inferior border of the upper wall of the orbit4 ,origin4--,from the sclerotic from the upper part of the ball4 ,insertion4--,to the upper part of the sheath of the optic nerve near the optic foramen4 ,shape4--,broad1 thin1 quadrate4 ,relations4--,inferiorly1 with the eyeball2 superiorly1 with the orbital wall1 with the superior oblique1 and with the superior rectus4 ,action4--,aids in pulling the nictitating membrane obliquely outward and downward over the forepart of the eyeball4 ,pyramidalis ,nictitans 7,fig4 #bf1 ,no4 ,b1 #h74 ,location4--,inferoposteriorly to the eyeball4 ,origin4--,from the lower nasal side of the eyeball4 ,insertion4--,the fibers converge toward the upper part of the optic nerve1 into a tendon which passes through a pulley at the free margin of the quadratus4 ,inserts to the lower part of the margin of the third eyelid1 the nictitans4 ,shape4--,pyramidal2 of thin layers of fibers4 ,relations4--,internally1 with the bony orbital wall2 externally1 with the eyeball4 ,action4--,aids the quadratus nictitans4 ,obliquus ,superior 7,fig4 #bf1 ,no4 ,b1 #e74 7,synonym4--,obliquus dorsalis47 ,location4--,superior to the eyeball4 ,illustration3 ,,fig4 #bf4--,structures of the eye and nasal passage4 ,a4 #a1 ,the anterior turbinated bone4 #b1 ,the posterior turbinated bones4 #c1 ,orbital gland4 #d1 ,ophthalmic division of the fifth pair of cranial nerves4 #e1 ,section through the cerebrum4 #f1 ,section through the skull showing the air spaces4 #g1 ,section through the comb4 #h1 ,anterior portion of the upper beak4 #i1 ,edge of the hard palate4 ,b4 ,the intrinsic muscles of the eyeball4 #a1 ,superior rectus4 #b1 ,internal rectus4 #c1 ,inferior rectus4 #d1 ,external rectus4 #e1 ,superior oblique4 #f1 ,inferior oblique4 #g1 ,quadratus4 #h1 ,pyramidalis4 #i1 ,optic nerve4 #aj1 ,edge of membrana nictitans4 ,c4 ,posterior part of the eye showing at the inferior portion of the ball the pyramidalis muscle at #a1 and at #b1 the quadratus4 #c1 ,optic nerve4 ,d4 ,inner view of the posterior part of the vitreous chamber4 #a1 ,sclerotic coat4 #b1 ,choroid coat4 #c1 ,retina4 #d1 ,pecten4 ,e4 ,longitudinal section through the eye of a hen4 #a1 ,cornea4 #b1 ,anterior chamber4 #c1 ,scleral ring4 #d1 ,crystalline lense4 #e1 ,iris4 #f1 ,retina4 #g1 ,sclerotic4 #h1 ,choroid4 #i1 ,pecten4 #aj1 ,optic nerve4 #aa1 ,vitreous chamber4 ,f4 ,an edge view of the crystalline lense of a hen showing it to be asymmetrical biconvex4 #a1 ,the anterior side4 #b1 ,the posterior side4 ,g4 ,the upper section through the anterior portion of the anterior turbinated bone showing one complete circle and the lower a section through the middle turbinated showing one and one-half turns4 ,origin4--,from the orbital septum just back of the inner canthus1 the fibers passing backward and forward4 ,insertion4--,into the sclera1 anterior to the sclerotic plates4 ,shape4--,small1 thin1 fan-shaped4 ,relations4--,with the eyeball1 superiorly2 at its extremities with the superior rectus1 interiorly4 ,action4--,rotates the eyeball4 ,obliquus ,inferior 7,fig4 #bf1 ,no4 ,b1 #f74 7,synonym4--,obliquus ventralis47 ,location4--,inferior to the eyeball4 ,origin4--,from the interorbital septum near the inner canthus of the eye4 ,insertion4--,by a broad expansion to the inferior portion of the eyeball4 ,shape4--,tendinous at its insertions2 fan-shaped as it passes downward and outward4 ,relations4--,internally1 with the eyeball2 and externally1 with the bony orbital wall1 with the inferior rectus muscle1 inferiorly4 ,action4--,aids in rotating the eye2 opposes the obliquus superior4 ,rectus ,superior 7,fig4 #bf1 ,no4 ,b1 #a74 7,synonym4--,rectus dorsalis47 ,location4--,superior to the eyeball4 ,origin4--,along the supero-posterior border of the optic foramen4 ,insertion4--,to the sclera just within the margin of the bony circle of the eye4 ,shape4--,flat1 thin4 ,relations4--,internally1 with the obliquus superior2 superiorly1 with the bony wall of the orbit4 ,action4--,to pull the eyeball upward4 ,rectus ,inferior 7,fig4 #bf1 ,no4 ,b1 #c74 7,synonym4--,rectus ventralis47 ,location4--,inferior to the eyeball4 ,origin4--,from the inferior border of the optic foramen4 ,insertion4--,to the lower portion of the eyeball within the margin of the bony circle of the eye4 ,shape4--,thin1 fan-shaped4 ,relations4--,superiorly1 with the eyeball2 inferiorly1 with the bony wall of the orbit4 ,action4--,pulls the eyeball downward4 ,rectus ,externus 7,fig4 #bf1 ,no4 ,b1 #d74 7,synonym4--,rectus lateralis47 ,location4--,external to the eyeball4 ,origin4--,by two heads infero-laterally to the optic foramen4 ,insertion4--,to the postero-external side of the eyeball4 ,shape4--,short1 fan-shaped4 ,relations4--,internally1 with the eyeball2 externally1 with the bony wall of the orbit4 ,action4--,pulls the eyeball outward4 ,rectus ,internus 7,fig4 #bf1 ,no4 ,b1 #b74 7,synonym4--,rectus medialis47 ,location4--,inner side of the eyeball4 ,origin4--,from the supero-anterior border of the optic foramen4 ,insertion4--,to the sclera on the anterior portion of the eyeball4 ,shape4--,thin1 fan-shaped4 ,relations4--,internally1 with the eyeball and with the pyramidalis2 externally1 with the bony wall of the orbit4 ,action4--,pulls the eyeball inward4 ,,the ,,muscles ,,of ,,the ,,ear ,circumconcha ,tensor tympani ,circumconcha 7,fig4 #g1 ,no4 #cb74 ,location4--,surrounds the external ear4 ,origin and ,insertion4--,the circumconcha1 surrounding the periphery of the ear1 is adherent to the skull and loosely to the skin1 and is attached to the outer terminus of the supra-occipital crest4 ,relations4--,internally1 with the skull2 externally1 with the skin4 ,action4--,relaxes the tympanum4 ,tensor ,tympani 7,fig4 #g1 ,no4 #ca74 ,location4--,external to the quadrate and to the external auditory meatus4 ,origin and ,insertion4--,from the surface of the quadrate and the inner end of the quadrato-jugal to the inner surface of the tympanum4 ,shape4--,a few fibers4 ,relations4--,internally1 with the quadrate and the quadrato-jugal2 externally1 the integumental duplicature4 ,action4--,tenses the tympanum4 ,,functions ,,of ,,muscles ,to cause the feathers on the top of the head to lie flat3 ,dermo-frontalis4 ,to raise the feathers along the superior part of the neck and along the dorsal region3 ,dermo-dorsalis4 ,to tense the patagial region3 ,dermo-tensor patagii1 ,dermo-temporalis4 ,to cause the feathers to lie close to the body3 ,dermo-humeralis1 ,dermo-pectoralis4 ,to tense the lateral cervical integument3 ,dermo-temporalis4 ,to support the lingual apparatus and superior larynx3 ,platysma myoides4 ,to manipulate the feathers and skin of the inferior part of the neck3 ,cleido-trachealis4 ,to control the skin in the shoulder region3 ,dermo-spinalis4 ,to cause the feathers of the back to lie close to the skin3 ,dermo-iliacus4 ,to depress the humeral region3 ,dermo-ulnaris4 ,to close the jaw3 ,temporalis1 ,pterygoideus internus1 ,pterygoideus externus1 ,masseter4 ,to open the jaw3 ,biventer maxilla1 ,entotympanic4 ,to raise the trachea and hyoid apparatus3 ,digastricus4 ,to elevate the tongue3 ,mylo-hyoideus4 ,to pull the tongue to one side3 ,singly#e-- ,cerato-hyoideus1 ,stylo-hyoideus4 ,alone when the larynx is fixed-- ,sterno-hyoideus4 ,those which protrude the tongue from the mouth3 ,together-- ,cerato-hyoideus1 ,genio-hyoideus4 ,to aid in deglutition3 ,when the base of the tongue is fixed-- ,sterno-hyoideus4 ,to depress the tongue3 ,together-- ,sterno-hyoideus4 ,to depress the tip of the tongue and elevate the base3 ,depressor glottis4 ,to elevate the hyoid arches3 ,cerato-glossus4 ,to extend the head3 ,complexus1 ,rectus capitis anticus minor4 ,to flex the head upon the neck3 ,flexor capitis inferior4 ,to extend the head on the neck and elevate the neck3 ,biventer cervicis4 ,to raise the neck upward3 ,longus colli posticus4 ,to flex each vertebra on the preceding or succeeding laterally3 ,obliquus colli1 ,intertransversales4 ,to pull the neck downward3 ,longus colli anterior4 ,to pull the head downward3 ,together-- ,rectus capitis lateralis1 ,trachelo-mastoideus4 ,to pull the head downward and to one side3 ,singly-- ,rectus capitis lateralis1 ,trachelo-mastoideus4 ,to approximate the spinous processes of the vertebr3 ,interspinales4 ,to approximate the vertebr in a supero-lateral direction3 ,interarticulares4 ,to flex the vertebr supero-laterally3 ,obliquo-transversales4 ,to extend the neck3 ,together when the first rib is fixed-- ,scalenus medius4 ,to close the glottis3 ,constrictor glottidis4 ,to open the glottis3 ,thyreo-arytenoideus4 ,to approximate the tracheal rings3 ,tracheo-lateralis4 ,to tense the inferior larynx3 ,broncho-trachealis posticus1 ,broncho-trachealis anticus1 ,broncho-trachealis brevis1 ,bronchialis posticus1 ,bronchialis anticus4 ,to relax the inferior larynx3 ,sterno-trachealis4 ,to aid in respiration3 ,when the first rib is fixed-- ,intercostales4 ,when wing is fixed-- ,latissimus dorsi1 ,dermo-cleido dorsalis4 ,when the scapula is fixed-- ,serratus magnus anticus1 ,serratus parvus anticus1 ,thoraco-scapularis1 ,levatores costarum1 ,appendico-costales1 ,triangularis sterni4 ,to flex the shoulder-joint3 ,latissimus dorsi4 ,to elevate the humerus3 ,latissimus dorsi4 ,to draw the scapula forward3 ,trapezius1 ,rhomboideus4 ,to close the wing3 ,teres et infraspinatus4 ,to extend the humerus3 ,coraco-humeralis1 ,scapulo-humeralis4 ,to pull the humerus upward and backward3 ,when the scapula is fixed-- ,supraspinatus4 ,to pull the coracoid outward3 ,subclavius4 ,to depress the wing3 ,coraco-brachialis4 ,to depress the scapula3 ,when the ribs are fixed-- ,thoraco-scapularis4 ,to rotate the humerus3 ,subscapularis4 ,to flex the forearm3 ,pronator brevis1 ,biceps1 ,brachialis anticus1 ,anconeus1 ,tensor patagii longus1 ,tensor patagii brevis4 ,to extend the arm3 ,deltoid4 ,to extend the antibrachial region3 ,triceps4 ,to raise and to draw the hand forward3 ,extensor metacarpi radialis longior4 ,to extend the digit3 ,extensor indicis longus1 ,extensor digitorum communis1 ,extensor proprius pollicis1 ,interosseous dorsalis4 ,to supinate the radial region3 ,supinator brevis4 ,to flex the hand3 ,flexor metacarpi radialis4 ,to pronate the forearm3 ,pronator brevis1 ,pronator longus4 ,to extend the hand on the forearm3 ,extensor ossis metacarpi pollicis4 ,to flex the digit3 ,flexor minimi digiti1 ,flexor digitorum sublimis1 ,flexor brevis pollicis1 ,flexor digitorum profundus1 ,interosseous palmaris4 ,to flex the hand upon the forearm3 ,flexor carpi ulnaris1 ,flexor carpi ulnaris brevior4 ,to rotate the hand toward the body3 ,flexor carpi ulnaris brevior4 ,to abduct the digits3 ,abductor minimi digiti4 ,to flex the metacarpus3 ,flexor metacarpi brevis4 ,to extend the leg3 ,sartorius4 ,to adduct the thigh3 ,sartorius1 ,adductor longus1 ,adductor magnus4 ,to abduct the thigh3 ,gluteus primus1 ,gluteus medius1 ,gluteus minimus4 ,to pull the thigh forward3 ,gluteus minimus1 ,gluteus medius4 ,to extend the leg upon the thigh3 ,extensor femoris1 ,vastus internus4 ,to extend the leg upon the knee3 ,vastus internus4 ,to flex the leg upon the thigh3 ,biceps flexor cruris1 ,semitendinosus1 ,semitendinosus accessorius1 ,semimembranosus4 ,to pull the tail down and to one side3 ,femoro-caudal4 ,to pull the head of the femur backward3 ,obturator externus4 ,to act as a posterior stay to the head of the femur3 ,obturator internus4 ,to pull the pelvis forward and to steady it on the head of the femur3 ,gemellus1 ,obturator internus1 ,obturator externus4 ,to extend the metatarsus on the tibia3 ,gastrocnemius1 ,soleus1 ,tibialis posticus4 ,to flex the toes3 ,peroneus longus1 ,flexor perforatus medius primus pedis1 ,flexor perforatus indicis secundus pedis1 ,flexor perforatus medius secundus pedis1 ,flexor perforatus indicis primus pedis1 ,flexor perforans digitorum profundus1 ,flexor longus hallucis1 ,flexor perforatus annularis primus pedis4 ,to flex the metatarsus on the tibia3 ,tibialis anticus4 ,to extend the toes3 ,extensor longus digitorum1 ,extensor hallucis brevis4 ,to flex the back laterally and to aid in raising the body4 ,sacro-lumbalis1 ,longissimus dorsi4 ,to elevate the tail3 ,levator coccygis1 ,levator caud4 ,to depress the tail3 ,depressor caud1 ,infracoccygis4 ,together-- ,depressor coccygis1 ,lateralis caud4 ,to pull the tail downward and to one side3 ,singly-- ,lateralis coccygis4 ,depressor coccygis1 ,lateralis caud4 ,to close the eyelids3 ,orbicularis palpebrarum4 ,to raise the superior eyelid3 ,levator palpebr superioris4 ,to pull the lower eyelid downward3 ,depressor palpebr inferioris4 ,to pull the membrana nictitans over the eyeball3 ,quadratus nictitans1 ,pyramidalis nictitans4 ,to rotate the eyeball3 ,obliquus superior1 ,obliquus inferior4 ,to pull the eyeball upward3 ,rectus superior4 ,to pull the eyeball downward3 ,rectus inferior4 ,to pull the eyeball outward3 ,rectus externus4 ,to pull the eyeball inward3 ,rectus internus4 ,to tense the ear drum3 ,tensor tympani4 ,to relax the ear drum3 ,circumconcha4 ,to depress the humerus3 ,pectoralis major4 ,to raise the humerus3 ,pectoralis secundus1 ,pectoralis tertius4 ,footnote #e3 ,muscles are arranged in pairs4 ,singly means one muscle acting alone1 i4e41 without its fellow2 together means acting both at the same time4 ,,splanchnology ,the ,digestive ,apparatus4--,this apparatus1 apparatus digestorius1 consists of the organs directly concerned in the reception of food1 in its passage through the body1 and in the expulsion of the unabsorbed portion4 ,for convenience1 these organs are grouped as follows3 the alimentary canal and the accessory organs4 ,the alimentary canal is a tube which extends from the mouth to the anus4 ,it has a complete lining of mucous membrane1 external to which is an almost continuous muscular coat4 ,the abdominal portion of the tube is largely covered with a serous membrane1 the visceral peritoneum4 ,the canal consists of the following consecutive segments3 mouth1 pharynx1 first portion of the esophagus1 crop1 second portion of the esophagus1 proventriculus1 gizzard1 small intestine1 large intestine1 and cloaca4 ,the accessory organs are beak1 tongue1 salivary glands1 liver1 and pancreas4 ,the ,mouth 7,fig4 #bg74--,the distinctive character of the mouth of the fowl consists1 in the absence of lips and teeth and instead of jaw bones of other animals1 of a beak4 ,the edge of the beak is covered by a horn-like gum4 ,the shape of the beak differs in the various classes of birds4 ,in the chicken the beak is short1 strong1 thick1 and pointed2 in palmipeds it is flattened4 ,the upper mandible extends out over the lower mandible4 ,the outer portion of the upper and the lower beaks is covered by a horny sheath4 ,there is no velum1 and the mouth cavity is extended rather continuously into the pharynx 7,fig4 #bg1 ,no4 #d74 ,the posterior cross bar of the hard palate 7,fig4 #bg1 ,no4 #e71 which possesses a row of filiform papill projecting backward1 marks the upper boundary line of the mouth2 while the posterior end of the tongue 7,fig4 #bg1 ,no4 #f71 likewise with a row of filiform papill1 marks its lower boundary line4 ,parts of the ,mouth4--,the mouth of fowls is divided into an upper and a lower half4 ,the upper half is divided into an anterior and a posterior part4 ,the anterior part extends from the anterior tip of the beak to the posterior nares4 ,it is further divided into an outer hard part and an inner soft part4 ,the outer part is covered by epithelium which may be considered as a continuation from the upper outer portion of the beak4 ,a portion of this is cornified4 ,the inner part is covered by a mucous membrane containing mucous glands1 nerves1 and blood-vessels4 ,in the posterior part of the upper half of the mouth1 are situated the posterior nares 7,fig4 #bg1 ,no4 #aj7 which appear as a longitudinal slit in the center of the hard palate4 ,there is also found in this part a furrow which contains the opening of the ,eustachian tubes1 or tub auditiv4 ,there are also two ridges near the same posterior part in which are red and white papill1 which may appear in rows1 and which contain mucous glands4 ,illustration3 ,,fig4 #bg4--,mouth and pharynx of a cock laid open4 #a1 ,eye4 #b1 ,edge of beak covered with a horn-like gum4 #c1 ,tongue4 #d1 ,pharynx4 #e1 ,posterior cross bar of hard palate4 #f1 ,posterior end of tongue4 #g1 ,anterior end of esophagus4 #h1 ,phrenum4 #i1 ,palatal papillaries4 #aj1 ,posterior nares4 ,the lower half of the mouth lies between the lower jaw bones and the walls of the mouth cavity4 ,the tongue is attached here by means of the phrenum 7,fig4 #bg1 ,no4 #h74 ,this half of the mouth forms a pocket-like structure which aids in taking up the food4 ,the mouth cavity is lined with stratified squamous epithelium1 continuous with that of the pharynx and the esophagus4 ,taste buds are located in the mucous membrane of the mouth4 ,illustration3 ,,fig4 #bh4--,various anatomical parts of the fowl4 ,c4 ,a section through the nasal region of the fowl4 #a1 ,nasal passages showing the turbinated bones dividing the nasal passage into the superior1 middle and inferior meati4 #b1 ,the infraorbital sinus4 #c1 ,the hard palate4 ,d4 ,herbst's touch corpuscle from the beak of a quail4 ,e4 ,a vertical section through the ductus cochlearis of a pigeon4 #a1 ,a blood-vessel4 #b1 ,the periosteum4 #c1 ,the bony structure4 #d1 ,the vascular integument4 #e4 ,the scala vestibuli4 #f1 ,the inner hyaline cylindrical cells4 #g1 ,the membrana tectoria4 #h1 ,the papilla acustica basilaris4 #i1 ,the membrana basilaris4 #aj1 ,the scala tympani4 #aa1 ,the ganglion of the cochlear nerve in the ramus basilaris4 #ab1 ,the periosteum 7,gadow74 ,f4 ,a corpuscle of the soft papilla of a duck's tongue4 ,j4 ,a transverse section through a feather papilla4 #a1 ,the pulp4 #b1 ,the malpighian layer4 #c1 ,the corium4 #d1 ,the stratum corneum of the papilla4 #e1 ,the malpighian cell group of the main shaft4 #f1 ,the horny sheath4 ,in many water fowls1 as geese and ducks1 the gum edge of the mandible has grooves extending crosswise1 in which are numerous terminals of the trigeminus nerve arranged as taste organs 7,fig4 #bi1 ,g and ,fig4 #bh1 ,d and ,f74 ,in many birds of prey and in water birds1 e4g41 the goose and the duck1 there is found at the base of the beak1 a very thin1 nervous or sensitive skin1 waxy in appearance1 called the ceroma4 ,illustration3 ,,fig4 #bi4--,various anatomical parts of the fowl4 ,a4 #a1 ,the superior semicircular canal4 #b1 ,the vestibular nerve4 #c1 ,the meatus auditorius internus--the entrance of the auditory nerve4 #d1 ,the entrance of the cochlear nerve4 #e1 ,posterior semicircular canal4 #f1 ,the ampulla4 ,b4 ,side papilla of the tongue4 #a and #b1 ,papill showing a fibrous central core supporting blood-vessels and nerves4 #c1 ,the basement membrane consisting of connective tissue4 ,g4 ,herbst's corpuscle of the tongue of a duck1 showing the capsule1 lamella and around the nerve zone1 numerous round bodies arranged in two rows4 ,h4 ,from the crist acoustica of the ampulla of the dove4 ,a1 ,a vertical section with isolated fiber cells4 #a and #b1 ,the nerve fibers4 #c1 ,the hair cells4 ,i4 ,a longitudinal section through a feather papilla showing a young feather4 #a1 ,the developing feather4 #b1 ,the horny sheath4 #c1 ,the epithelium4 #d1 ,stratum corneum4 #e1 ,stratum malpighi4 #f1 ,corium4 #g1 ,malpighian cell group of the follicle4 ,the ,hard ,palate4--,the hard palate1 palatum durum1 forming the roof of the mouth has for its boundaries the beak anteriorly1 the mandibular arches laterally1 and the pharynx posteriorly4 ,it has four or five transverse bars1 projecting posteriorly from each of which is a row of filiform papill 7,figs4 #bg and #bi74 ,illustration3 ,,fig4 #cj4--;,a section through the wall of the crop of a hen4 #a1 ,the outer muscular layer showing longitudinal fibers4 #b1 ,the inner muscular layer showing the sectioned ends of the bundles of muscle fibers4 #c1 ,stratified squamous epithelium4 #d1 ,the outer surface or lumen of a fold4 #e1 ,the stroma1 muscularis mucosa1 and submucosa4 ,the beak 7,fig4 #d1 ,no4 #a7 with little if any aid from the tongue1 is the prehensile organ4 ,the ,tongue 7,fig4 #bg1 ,no4 #c74 ,location4--,the tongue 7lingua7 of the fowl is situated in the floor of the mouth between the rami of the lower mandible1 and is slung to the cranium by the cerato-branchial element of the os hyoideum 7,fig4 #ah1 ,no4 #b74 ,shape4--,the tongue1 is pointed in front and wide behind1 shaped like an ,indian arrow-head1 and is supported by the bony and cartilaginous hyoid apparatus 7,fig4 #i1 ,a74 ,illustration3 ,,fig4 #ca4--,the visceral organs of the hen4 #a1 ,tongue4 #b1 ,larynx4 #c1 ,glottis4 #d1 ,first portion of the esophagus4 #e1 ,crop4 #f1 ,second portion of the esophagus4 #g1 ,proventriculus4 #h1 ,duodenum4 #i1 ,free or floating portion of the small intestine4 #aj1 ,mesentery supporting the free portion of the small intestine4 #aa1 ,cca4 #ab1 ,rectum or large intestine4 #ac1 ,cloaca4 #ad1 ,anus4 #ae1 ,liver4 #af1 ,gall-bladder4 #ag1 ,pancreas4 #ah1 ,gizzard4 #ai1 ,trachea4 #bj1 ,lungs4 #ba1 ,spleen4 ,structure4--,the free part of the tongue consists of two long tubes which are formed by the rolling in of the ventral sides of its horny coverings4 ,the dorsal plate1 which constitutes one-half of the horny sheath1 does not form a part of the tubes1 but ends in the region of the point of the entoglossum4 ,the top surface is covered by a thick stratum corneum1 giving it a rather horny surface4 ,glands occur in the posterior part of the tongue4 ,while not so freely movable as in mammals1 the tongues of birds are very flexible4 ,the ,pharynx 7,fig4 #bg74 ,location4--,the anterior part of the pharynx joins with the mouth and the posterior part with the upper portion of the esophagus and the superior larynx4 ,the pharynx is bounded anteriorly by the base of the tongue and by the posterior edge of the hard palate4 ,posteriorly1 it is marked by the entrance of the esophagus and by a ridge of filiform papill located on the supero-posterior part of the larynx1 called the palatal papillaries4 ,a few filiform papill stud the roof4 ,the pharynx communicates anteriorly with the posterior nares and the mouth1 and1 posteriorly1 with the esophagus and the larynx4 ,shape4--,the pharynx is a musculo-membranous sac4 ,structure4--,the pharynx is lined with a mucous membrane covered by squamous epithelium4 ,the mucous membrane is thrown into irregular folds4 ,the bird has two ,eustachian tubes4 ,pneumatic apertures conduct the air from the ,eustachian tubes to the pericranial diplo4 ,in the posterior pharyngeal roof is situated the infundibular crevice4 ,function4--,the function of the pharynx is to give passage for the air from the posterior nares to the larynx1 and to give passage for the food from the mouth to the esophagus4 ,glands ,adjacent to the ,mouth and to the ,pharynx4--,the mucous membrane adjacent to the glottis and in the roof of the mouth contains alveolar glands4 ,the angular gland of the mouth1 located beneath the zygomatic arch1 by some anatomists is considered the rudimentary parotid gland4 ,the sublingual glands1 or glandul sublinguales1 are well developed 7,fig4 #ag1 ,no4 ,b1 #d74 ,they form conical masses1 with the apex directed anteriorly1 and occupy a portion of the intermaxillary space4 ,several ducts from these glands open into the mouth cavity4 ,in the palatine region there are also located glands called the palatine glands1 which open by many stomata upon the surface4 ,the ,esophagus 7,fig4 #ah1 ,no4 #f74 ,location and ,shape4--,the esophagus is a musculo-membranous tube1 capable of great distension1 which extends from the pharynx to the proventriculus 7,fig4 #ce1 ,no4 #a1 and #c74 ,the esophagus communicates anteriorly with the pharynx4 ,it extends down the neck1 lying supero-laterally with regard to the trachea and toward the right side4 ,it enters the thorax above the trachea1 and1 passing through between the bronchi1 terminates into the proventriculus4 ,at the entrance of the thorax and just to the right of the median line1 it expands into the crop which divides it into two portions1 designated as the first and the second4 ,the first portion of the esophagus is the longer1 the length depending upon the size and kind of fowl4 ,structure4--,the wall is composed of four coats1 the mucous membrane1 the submucosa1 the muscular coats1 and the fibrous sheath or tunic4 ,the mucous membrane is pale and is covered with stratified squamous epithelium4 ,the mucous membrane is loosely attached to the muscular coat by the submucosa4 ,except during deglutition it lies in longitudinal folds which obliterate the lumen4 ,opening from the mucosa are lenticular glands1 which may be seen on inflating an esophagus and looking through its transparent walls4 ,the muscular coat of the esophagus is divided into two layers1 an outer longitudinal and an inner circular layer4 ,the outer fibrous sheath connects the esophagus loosely to the surrounding structures4 ,function4--,the function of the esophagus is to give passage way for the food from the pharynx to the crop and from the crop to the proventriculus4 ,the ,crop 7,fig4 #ce1 ,no4 #b2 ,figs4 #cj and #ca74 ,location and ,shape4--,the crop1 or ingluvies1 saccular in shape1 is located at the entrance of the thorax and just to the right of the median line4 ,the first portion of the esophagus empties into the crop superiorly and inferiorly the crop opens into the second portion of the esophagus4 ,like the esophagus the crop is capable of great distension4 ,structure4--,the wall of the crop is composed of four coats1 the mucous membrane1 submucosa1 muscular and the outer fibrous4 ,the crop is lined with mucous membrane containing mucous glands which secrete a mucus to keep the surface moist4 ,the surface of the mucous membrane is covered by stratified squamous epithelium4 ,the submucosa connects the mucous membrane to the muscular coat4 ,the wall of the crop is provided with strong muscles4 ,the fibrous coat1 or tunic1 connects it with the surrounding structures4 ,function4--,the crop is a storehouse for the food during the hours of feeding1 the food when needed by the stomach being gradually discharged from the crop by the contraction of its muscular walls4 ,the subcutaneous cervical muscles which cover this reservoir aid in this discharge4 ,in the act of deglutition1 the food1 after being subjected to the fluid supplied in the mouth by the adjacent glands1 is poised upon the tongue and swallowed partly by a sudden jerk of the head1 and partly by means of the pressure of the tongue against the hard palate1 the food then passes down the esophagus and lodges first in the crop1 till needed by the stomach1 when it is passed through the second portion of the esophagus to the first portion of the stomach1 the proventriculus4 ,the time during which food remains in the crop depends upon the nature of the food4 ,animal food will1 in part1 be retained about eight hours and vegetable foods may not all be passed on for from sixteen to eighteen hours4 ,the ,stomach 7,fig4 #ca1 ,no4 #g2 ,fig4 #cb1 ,b74--,the stomach1 or ventriculus1 of fowls is made up of two portions1 namely1 the pars glandularis1 or proventriculus1 and the pars muscularis1 or gizzard4 ,the ,proventriculus4 ,location4--,the proventriculus lies in the superior part of the groove formed by the two lobes of the liver1 is inferior to the aorta1 and is directed slightly to the left1 communicating anteriorly with the second portion of the esophagus and posteriorly emptying into the pars muscularis1 the gizzard4 ,shape4--,the proventriculus is round transversely and elongated1 in fact1 nearly fusiform4 ,in the hen of average size it measures about #a4fb inches long and #j4h inch in diameter4 ,structure4--,the wall of the proventriculus has four coats1 the mucous1 submucous1 muscular1 and serous4 ,the inner mucous coat which is raised in folds1 is lined with columnar epithelial cells4 ,the mucous membrane contains lymphoid tissue4 ,the mucous coat throughout contains simple tubular glands which secrete a highly acid fluid which finds its way to the surface through small cylindrical ducts lying at right angles to the inner surface of the mucous membrane 7,fig4 #cb1 ,no4 ,b1 #a74 ,illustration3 ,,fig4 #cb4--;,gizzard and stomach of the fowl4 ,a4 #a1 ,alveolar glands4 #b1 ,mucous membrane of the inner surface of the proventriculus showing the tubular glands4 #c1 ,connective tissue between the alveolar glands4 #d1 ,an artery4 #e1 ,muscularis mucosa4 ,b4 ,photograph of the proventriculus and gizzard4 #a1 ,proventriculus showing stomata of glands4 #b1 ,end of duodenum4 #c1 ,gizzard showing hornified epithelium formed into grooves4 #d1 ,the heavy muscular walls4 ,the submucosa1 connects the mucous and muscular coats and the muscularis layer throws the mucous membrane into folds4 ,outside the muscularis mucosa there is another layer 7,fig4 #cb1 ,a71 of simple tubular glands1 grouped in lobules1 and lined by cuboidal cells and separated from each other by clefts4 ,these tubular glands converge toward the center and open into the same cavity4 ,the middle muscular coat can be divided into three layers3 two thin1 longitudinal layers1 and a thick1 circular layer interposed between the other two4 ,function4--,the function of the proventriculus appears to be to soak the food with a secretion4 ,the secretion from the proventriculus is similar to that produced by the fundus glands of the stomach of mammals4 ,it contains acid and a ferment-pepsin4 ,the ,gizzard 7,fig4 #ca1 ,no4 #ah74 ,location4--,the gizzard1 or muscular stomach1 occupies a portion of the central part of the abdominal cavity 7,fig4 #cc1 ,no4 #d74 ,it lies slightly to the left and just behind the liver1 the proventriculus1 and the spleen1 and rests upon a mass of intestines4 ,the gizzard communicates at its anterior portion with the proventriculus and with the duodenum4 ,these openings are close together4 ,the gizzards of a large number of hens of average size averaged in weight as follows3 full1 #j4bae pound2 empty1 #j4abf pound4 ,the gizzard stands perpendicularly and somewhat obliquely in the abdominal cavity4 ,shape4--,in shape the gizzard is roundish1 flattened laterally4 ,structure4--,the walls of the gizzard are very thick and are made up of three coats3 mucous1 muscular1 and serous4 ,the cavity of the gizzard is covered by a thick skin-like structure possessing a heavy stratified squamous epithelial layer which is thrown somewhat into ridges 7,fig4 #cb1 ,b74 ,this membrane becomes thinnest near the edges4 ,the mucous membrane1 being cornified and readily detachable1 is by some anatomists considered as a special membrane 7,fig4 #cg1 ,b74 ,at the pyloric opening there is a valve formed by a fold of the mucous membrane1 which prevents grit and large particles of food from passing out of the gizzard4 ,illustration3 ,,fig4 #cc4--,view of viscera of the left side of a hen4 #a1 ,the base of the heart4 #b1 ,proventriculus4 #c1 ,left lobe of the liver4 #d1 ,gizzard4 #e1 ,end of the duodenal loop4 #f1 ,pancreas4 #g1 ,free portion of the small intestine4 #h1 ,lungs4 #i1 ,diaphragm4 ,illustration3 ,,fig4 #cd4--,view of the viscera of the right side of a hen4 #a1 ,base of the heart4 #b1 ,lungs4 #c1 ,right lobe of the liver4 #d1 ,duodenal loop4 #e1 ,pancreas4 #f1 ,ccum4 #g1 ,large intestine or rectum4 #h1 ,free portion of the floating small intestine4 #i1 ,gall-bladder4 #aj1 ,right kidney4 #aa1 ,the ribs4 ,note the lungs pushing up between them4 ,on each side it has a powerful fleshy muscle1 the muscularis lateralis4 ,these musculares laterales are hemispherical1 consist of very closely packed fibers extending transversely1 and are attached to strong anterior and posterior ligamentous tendons4 ,they are joined at the edge of the organ by a strong aponeurosis4 ,the muscular fibers are red but do not possess cross striations2 they are of the smooth type4 ,the muscularis intermedii1 thinner and less developed than the musculares laterales1 occurs on each of the anterior and the posterior parts of the gizzard4 ,the serous coat covers over the greater part of the external surface of the gizzard and closely adheres to the muscular coat4 ,function4--,the hard callous pads of the gizzard1 operated by the powerful muscles above described1 together with grit1 act like mill stones and make reduction to fineness very complete4 ,at the posterior part there is a sacculated portion containing glands of the long tubular type which secrete a fluid ferment similar to that secreted by the glands of the pyloric portion of the stomach of mammals4 ,these glands also exist in a small band near the entrance of the gizzard4 ,here the food is mixed with strongly acid secretion containing pepsin which makes gastric digestion perfect4 ,illustration3 ,,fig4 #ce4--;,a median antero-posterior section through the body of a #a-pound pullet4 #a1 ,first portion of the esophagus4 #b1 ,crop4 #c1 ,second portion of the intestine4 #d1 ,proventriculus4 #e1 ,gizzard4 #f1 ,spleen4 #g1 ,liver4 #h1 ,heart4 #i1 ,point where duodenum was severed from gizzard4 #aj1 ,point where duodenum was severed4 #aa1 ,duodenum4 #ab1 ,pancreas4 #ac1 ,ccum4 #ad1 ,floating small intestine4 #ae1 ,ovary4 #af1 ,oil sac4 ,the ,small ,intestine 7,fig4 #ca1 ,no4 #h and #i74--,the small intestine1 intestinum tenue1 is the tube which connects the gizzard with the large intestine4 ,it is divided into two parts1 the duodenum and the free portion4 ,of the three parts as considered in the mammalian intestine1 only the first1 the duodenum1 can be distinguished4 ,there is no demarcation between the jejunum and the ileum4 ,the jejunum and the ileum or that part which represents these sections1 are in coils suspended from the free border of the mesentery the other border of which is1 in turn1 attached to the dorsal wall 7,fig4 #fd74 ,the length of the small intestine in a hen of average size is about #fa4g inches4 ,illustration3 ,,fig4 #cf4 ,a4 ,section of the duodenum of the fowl4 #a1 ,villus4 #b1 ,gland4 #c1 ,mass of lymphoid tissue4 #d1 ,muscularis mucosa4 #e1 ,longitudinal layer4 #f1 ,circular muscular layer4 #g1 ,serous layer4 ,b4 ,a section from ,a at a4 #a1 ,the striated free border of the cells4 #b1 ,goblet cell4 #c1 ,columnar cell4 #d1 ,nucleus of cell4 ,the wall of the small intestine is provided with four coats1 as follows3 a mucous1 submucous1 muscular coat made up of two layers--the outer1 longitudinal and the inner circular layer1 and an external serous4 ,illustration3 ,,fig4 #cg4--;,histological studies of various anatomical parts4 ,a4 ,a transverse section of the first portion of the esophagus of a fowl4 #a1 ,the outer longitudinal muscular layer4 #b1 ,the circular muscular layer4 #c1 ,the submucosa4 #d1 ,the muscularis mucosa4 #e1 ,stroma4 #f1 ,epithelial layer4 #g1 ,the lenticular glands4 #h1 ,the lumen4 ,b4 ,a transverse section of the proventriculus4 #a1 ,the outer longitudinal muscular layer4 #b1 ,the middle muscular layer4 #c1 ,the inner longitudinal muscular layer4 #d1 ,stroma4 #e1 ,the muscularis mucosa4 #f1 ,the submucosa4 #g1 ,stroma4 #h1 ,tubular glands4 #i1 ,tubulo-alveolar glands4 #aj1 ,a tubulo-alveolar gland with the tubular glands cut transversely1 #aa1 ,the lumen of the proventriculus4 ,c4 ,a section of the inner wall of the gizzard4 #a1 ,the hyaline mucous membrane4 #b1 ,branched tubular glands4 #c1 ,submucosa4 #d1 ,muscle4 #e1 ,a connective tissue septum4 ,d4 ,a transverse section of the small intestines4 #a1 ,the outer longitudinal muscular layer4 #b1 ,the inner circular muscular layer4 #c1 ,the muscularis mucosa4 #d1 ,the stroma4 #e1 ,brunner's glands4 #f1 ,a villus4 #g1 ,mass of lymphoid tissue4 ,e4 ,a transverse section through the cecum4 #a1 ,the outer longitudinal muscular layer4 #b1 ,the inner circular muscular layer4 #c1 ,the submucosa4 #d1 ,the muscularis mucosa4 #e1 ,the stroma4 #f1 ,tubular glands4 #g1 ,the lumen4 ,f4 ,the cerebellum showing the arbo-vit4 #a1 ,white1 fiber portion4 #b1 ,the granular layer4 #c1 ,the layer of ,purkinje cells4 #d1 ,the molecular layer4 ,the mucous membrane which lines the intestine is thick1 soft1 and highly vascular4 ,it has a velvety appearance1 due to numerous long1 thin projecting villi4 ,the villi 7,fig4 #cf1 ,a7 are concerned in the absorption of the digested food1 absorbing principally the emulsified fats4 ,each villus is covered with a single layer of high columnar epithelial cells4 ,some of these1 the so-called goblet cells1 provide mucin which lubricates the mucous surface4 ,these cells are found in all mucous surfaces and prevent the surface from becoming dry4 ,there are a few goblet cells near the summits of the villi4 ,openings of simple intestinal tubular glands the duodenal glands1 or the glands formerly known as ,brunner's glands1 are located between the villi4 ,these glands secrete the succus entericus1 or intestinal juice4 ,these openings1 or stomata1 are lined with granular cells4 ,the reaction of the contents of the small intestine is strongly acid1 but gradually less so in proportion to the distance down the intestinal tract until the cca are reached1 where the reaction is found to be faintly acid1 neutral1 or slightly alkaline4 ,function4--,the function of the small intestine is that of digestion and absorption4 ,the ,duodenum4 ,location and ,shape4--,the duodenum1 a small tube1 originates from the gizzard about inch to the right of the entrance of the proventriculus4 ,extending from left to right1 it passes under and behind the gizzard along the inner side of the right abdominal wall backward to the posterior portion of the wall1 and a trifle more than half way toward the left side1 where the loop rests4 ,this loop1 the duodenal loop1 is about #e inches in length 7,fig4 #ca1 ,no4 #h74 ,the two branches of the loop the first and the second portions or the descending and ascending limbs1 are loosely held by connective tissue1 and have the pancreas lodged between them4 ,the ,free ,portion of the ,small ,intestine4 ,location4--,that section of the small intestine following the duodenum is called the free portion of the small intestine and occupies the space between the abdominal air-sac and the median line of the abdominal cavity4 ,it is disposed in coils and is suspended from the dorsal wall of the abdomen by a thin membrane1 the mesentery4 ,the bile ducts enter the small intestine about #ad inches from its point of origin4 ,the pancreas also pours its contents into the small intestine4 ,the ,large ,intestine 7,fig4 #ca1 ,no4 #ab74 ,location4--,the large intestine extends in a straight line along the inferior border of the vertebral column communicating anteriorly with the small intestine1 and the cca and posteriorly with the cloaca4 ,shape4--,the diameter of the large intestine is approximately twice that of the small intestine4 ,in fowls of average size its mean length is #d4fa inches4 ,the large intestine has sometimes been spoken of as the rectum1 or straight gut4 ,structure4--,like the small intestine the large intestine has four coats3 an inner mucous1 a submucous1 a middle muscular and an outer serous4 ,the folds of mucous membrane of the large intestine have tubular glands lined with columnar cells 7,fig4 #cg1 ,a1 ,no4 #a74 ,function4--,the large intestine is similar in function to that of the small intestine1 in that digestion and absorption may take place within it4 ,the ,cca 7,fig4 #ca1 ,no4 #aa74 ,location4--,the fowl has two cca extending forward from their point of origin at the juncture of the small and large intestine4 ,shape4--,the cca average #g4fa inches in length4 ,they are large in caliber toward the blind extremity and are constricted near their origin4 ,structure4--,the parietal coats are continued from the small intestine4 ,ebarth has described an elevated body in the ccum1 which is located about #d millimeters from the opening and is composed entirely of lymphoid tissue4 ,illustration3 ,,fig4 #cg;,a4--,photomicrograph of a transverse section of large intestine and oviduct just anterior to the cloaca1 showing the tubular glands of the large intestines1 mucosa of oviduct with intervening structures4 #a1 ,the tubular glands of large intestine1 or rectum4 #b1 ,muscular wall of intestine4 #c1 ,wall of the oviduct4 #d1 ,mucosa of the oviduct4 ,the cca are usually partly filled with a soft pultaceous material of a pasty consistency4 ,the ,cloaca 7,fig4 #ca1 ,no4 #ac74 ,location4--,the rectum opens by a circular1 valvular orifice into the dilated portion just in front of the anus1 which dilatation is called the cloaca4 ,shape4--,the cloaca is saccular in shape4 ,structure4--,the cloaca is divided into two portions1 the coprodeumal and the urodeumal4 ,that portion of the cloaca into which the intestine empties is called the coprodeum2 and the ureter and oviduct empty into the urodeum4 ,the seminiferous tubules1 carrying the semen from the testes in the male empty in teatlike projections on the cloacal mucous membrane into the urodeumal portion4 ,the cloacal walls are similar in structure to the large intestines4 ,on the dorsal wall of the cloaca between it and the spine1 is a small sac1 called the bursa of ,fabricius1 which has a duct communicating with the cloaca4 ,the mucous membrane of this sac is thrown into folds and is studded with glands4 ,the bursa of ,fabricius is larger in the young than in the adult bird4 ,it apparently atrophies as the bird becomes older4 ,when the bird is four months old this bursa is best developed1 and at this age it may be as large as #b or #c centimeters in diameter4 ,function4--,the function of the cloaca is to give passage way to the feces1 the urine1 and the egg and to act as an organ of copulation4 ,course of the ,food4--,the food first enters the mouth1 after being picked up by aid of the beak4 ,from here it passes through the pharynx and first portion of the esophagus to the crop1 without mastication1 as the bird is not provided with teeth4 ,the food is passed from the crop by aid of its muscular walls as needed2 thence through the second portion of the esophagus to the proventriculus1 an expansion in the digestive tube just before it terminates in the gizzard4 ,the glands of the proventriculus produce a secretion in which the food is soaked before passing into the gizzard4 ,the gizzard is provided with strong muscular walls which1 by aid of grit1 thoroughly reduce the food to fineness4 ,from the gizzard the food passes through the first portion of the small intestine1 where it is subjected to the action of the bile from the liver1 the pancreatic juice from the pancreas1 and of the succus entericus from the glands of the intestinal wall4 ,the food is then passed into the cca4 ,the indigestible portion of the food passes from the cca through the large intestine1 or rectum1 to the cloaca and thence to the external world4 ,the digestive functions of the bird are very potent and rapid4 ,this compensates for the waste caused by their extensive1 frequent1 and energetic motions1 and is in accordance with the rapidity of their circulation and their high state of irritability4 ,,the ,,accessory ,,organs ,,of ,,digestion ,the accessory organs of digestion are the liver1 pancreas1 and some anatomists include also the spleen4 ,the first two manufacture fluids containing ferments which aid in splitting or digesting the food4 ,the ,liver 7,figs4 #ca1 #cc and #cd74 ,location4--,the liver1 hepar1 lies ventrally and posteriorly to the heart4 ,it is related anteriorly with the diaphragm1 inferiorly with the sternum1 posteriorly with the gizzard and intestine1 and superiorly with the ovary1 oviduct and proventriculus and laterally with the abdominal wall4 ,shape4--,the liver is a voluminous deep livid brown gland1 soft and friable in texture4 ,it is divided into two principal lobes1 a right and a left4 ,the right lobe is larger than the left4 ,in the hen of average size the liver weighs #ce grams4 ,the parietal surface is convex and smooth4 ,the surface which lies against the viscera is irregularly concave4 ,the visceral surface furnishes exit for the bile duct and passage for the nerves and blood-vessels4 ,this part is called the porta4 ,the left lobe may be cleft from below so deeply as to form two lobes on that side4 ,structure4--,each lobe is covered by a double serous membrane1 one closely adherent1 the other surrounding the structure loosely4 ,these tunics1 which are reflections of the peritoneum1 are continued from the base of the liver1 over both the anterior1 and the posterior surface4 ,the loose layer is formed by the air cells surrounding the lobes4 ,the thin border of the liver is usually free4 ,the two lobes of the liver are connected by a narrow isthmus of liver tissue4 ,occasionally there is a bird in which there occurs a lobus ,spigelii located at the posterior of the liver between the two principal lobes4 ,the apex of the heart sacculates the diaphragm backward1 so that part of this apex lies between the right and the left lobes 7,fig4 #dc1 ,no4 #f and #g74 ,a ligament1 the falciform1 extends from the apex of the pericardial membrane1 and attaching it rather firmly to the central connective tissue1 or interlobar ligament4 ,this ligament also has attachments to the inner surface of the sternum4 ,the broad ligament of the liver is formed posteriorly by a fold of the peritoneum4 ,the interlobar1 or principal1 ligament of the liver is formed by a large and strong duplicature of the peritoneum1 which makes a longitudinal division in the abdominal cavity similar to the lateral division made by the thoracic mediastinum in mammals4 ,it is reflected upon the pericardium from the linea alba and the middle line of the sternum1 and passes deeply into the interspace of the lobes of the liver4 ,it is attached to these lobes throughout their whole length and connects them below to one side of the gizzard4 ,the lateral and posterior part of the liver attach to the adjacent air cells1 and the whole viscus is thus kept fixed in its position during rapid and violent movements of the bird4 ,the remains of the umbilical veins are traceable within the duplicature of the membranes forming the septum4 ,these remains thus represent the round ligament of mammals4 ,illustration3 ,,fig4 #ch4--;,cellular structure of liver1 pancreas1 and trachea4 ,a4 ,liver4 #a1 ,liver cells4 #b1 ,sinusoid4 #d1 ,nucleus of cells4 ,b4 ,pancreas4 #a1 ,island of ,langerhans4 #b1 ,alveolar cells4 #c1 ,duct4 ,c4 ,trachea4 #a1 ,ciliated epithelia4 #b1 ,glands4 #c1 ,hyaline cartilage4 ,d4 ,section of wall of ovum at ,fig4 #eg letter d4 #a1 ,yolk4 #b1 ,granular membrane4 #c1 ,theca4 #d1 ,blood-vessel4 ,a microscopic study of the liver of the fowl shows a compact mass of liver cells polyhedral in shape1 with large nuclei 7,fig4 #ch1 ,a74 ,the liver tissue differs from that of mammals in that there is no clearly outlined lobular arrangement2 neither is the outline of the individual cell so well marked4 ,the parenchymatous portion is made up of columns of liver tissue4 ,these columns anastomose and show narrow channels between4 ,they are best seen in the young chick4 ,function4--,one of the functions of the liver is to secrete bile4 ,a gall-bladder1 which receives part of the bile secreted by the right lobe of the liver1 is located on the posterior face of this lobe4 ,extending from this gall-bladder there is a duct1 the cystic duct1 which empties into the small intestine toward the extremity of the second branch of the duodenal loop4 ,another duct called the hepatic duct1 proceeds directly from the two lobes of the liver and empties into the intestine just in front of the cystic duct4 ,the ,pancreas 7,fig4 #ca1 ,no4 #ag74 ,location and ,shape4--,the pancreas1 an organ lying in the duodenal loop is a yellowish-white1 lobulated gland1 elongated in shape4 ,its average length in fowls of average size is #d4if inches1 and the average weight about #j4jjh pound4 ,the pancreas is divided into lobes1 which in turn are divided into lobules4 ,structure4--,the pancreas has a supporting connective tissue4 ,the lobules are made up of small alveolar glands1 which are lined with columnar epithelial cells4 ,the ducts leading from the alveoli are small2 these unite to form larger ducts in which the epithelium is taller4 ,between the alveoli throughout the pancreas there are clusters of polyhedral cells which form the islands of ,langerhans4 ,these islands are said to produce an internal secretion1 or hormone1 which is absorbed by the blood or lymph capillaries and thus enters the circulation 7,fig4 #ch1 ,b74 ,function4--,the function of the pancreas is to secrete a fluid containing digestive ferments4 ,the ,spleen 7,fig4 #ca1 ,no4 #ba74 ,location4--,the spleen1 or lien1 lies in a triangle formed by the proventriculus1 the liver1 and the gizzard4 ,shape4--,it is a reddish-brown body shaped like a buckeye1 is small in size1 weighing only about #j4jje pound4 ,structure4--,the outer surface of the spleen is covered by a reflection of the peritoneum4 ,after this covering is removed1 there is observed a firm1 white1 fibrous layer1 the cortical portion4 ,this covering sends into the interior small and large trabecul1 forming a framework and dividing it into acini1 or compartments4 ,the spaces are filled with a dark red parenchymatous material called splenic pulp4 ,the framework1 in both deep and surface portions1 are found elastic fibers and smooth muscular fibers4 ,the spleen is essentially a lymphatic organ1 its peculiar structure depending largely upon the arrangement of the blood-vessels4 ,compact lymphatic tissue occurs in the spleen in spherical1 oval1 or cylindrical collections of closely packed lymphoid cells4 ,these masses are known as the ,malpighian bodies1 or splenic corpuscles4 ,they are distributed throughout the splenic pulp4 ,each splenic corpuscle contains one or more small arteries4 ,these extend near the periphery of the corpuscle and more rarely in the center4 ,the splenic artery passes in and the splenic veins out at the hilum which is located on the concave1 or attached1 side of the spleen4 ,the splenic artery1 upon entering the organ1 at once branches1 the trabecul forming a support for the vessels4 ,after the arteries have entered the hilum1 as stated above1 they divide into many branches which follow the septa of the connective tissue4 ,at first the arteries are accompanied by branches of the splenic veins4 ,soon1 however1 the arteries leave the veins and the septa1 and penetrate the splenic pulp4 ,in the splenic pulp the adventitia of the smaller arteries assume the character of reticular tissue1 and become infiltrated with lymphoid cells4 ,this infiltration forms masses which are called the splenic corpuscles1 or ,malpighian bodies4 ,the terminal arteries break up into capillaries1 which still retain an adventitia1 and empty into border spaces1 or sinuses1 sometimes spoken of as ampull4 ,these sinuses in turn empty into cavernous sinuses of the splenic pulp4 ,from these are finally formed the venules2 and the collections of venules form the splenic veins through which the blood gains exit from the spleen4 ,the ,abdominal and ,pelvic ,cavities4--,in birds the abdominal cavity is divided into two smaller cavities by a fibrous septum4 ,the anterior cavity representing the abdominal contains the liver1 and the other representing the pelvic contains the gizzard1 intestines and oviduct4 ,the ,peritoneum and the ,mesentery4--,the abdominal and pelvic cavities are lined by the peritoneum4 ,like all serous membranes this is composed of a parietal and a visceral portion1 which together form a complete sac1 with the organs it covers situated on the outer side4 ,the peritoneum like other serous membranes consists of a mesothelial and a submesothelial portion1 the cells of the former being arranged in a single layer4 ,since a serous membrane is so arranged as to line a closed cavity1 and at the same time to cover its contents1 it follows that the entire membrane must be a closed sac1 the mesothelial layer being on the inside2 such a sac is called a serous sac1 or cavity4 ,synovial membranes are also regarded as a variety of serous membranes4 ,the fold1 or layer1 of the membrane which lines the cavity is called the parietal1 that which covers the greater part of the organs contained therein is called the visceral portion2 the two surfaces contacting1 and gliding upon each other1 are lubricated by a fluid secretion contained in the sac2 hence one use of these membranes is to prevent friction between the walls of cavities and the organs contained therein4 ,serous membranes line the abdominal cavity1 pericardium1 cavities of the heart and is continuous throughout the vascular structures4 ,illustration3 ,,fig4 #ci4--;,a transverse section of body of hen through #ae1 ,fig4 #cd4 ,r1 ,right side4 ,l1 ,left side4 #a1 ,spinal cord4 #b1 ,esophagus4 #c1 ,trachea4 #d1 ,skin4 #e1 ,pectoral muscles4 ,the serous membrane besides covering the external surface of the viscera1 double folds pass from one organ to another1 or from an organ to the parietes of the cavity4 ,these double folds of the peritoneum are known as ligaments1 or as mesenteries4 ,in ligaments the two folds are strengthened by an interposed layer of fibro-elastic tissue4 ,a mesentery is a broad1 double fold of peritoneum1 attached to the abdominal parietes above1 and containing a portion of the intestine in its free or remote extremity4 ,between its folds we find blood-vessels1 nerves1 and lymphatics or lacteals1 hence it permits vascular and nervous communications with the organ attached to it4 ,the free portion of the small intestine is attached to the free margin of the mesentery4 ,,the ,,relations ,,of ,,the ,,visceral ,,organs ,,of ,,the ,,domestic ,,fowl ,illustration3 ,,fig4 #dj4--,transverse section through the body of a hen through #ad1 ,fig4 #cd4 ,r1 ,right side4 ,l1 ,left side4 #a1 ,spinal cord4 #b1 ,esophagus4 #c1 ,trachea near inferior larynx4 #d1 ,lungs4 #e1 ,pectoral muscles4 ,figure #cc shows a fowl with the left abdominal wall and the left thoracic wall removed4 ,no4 #a in this figure shows the base of the heart in front of the left lobe of the liver4 ,above the liver is the proventriculus2 above this1 the diaphragm2 and above the diaphragm and the base of the heart the left lung occupying the superior part of the thoracic cavity1 and that there is no distinct pleural sac1 as in mammals but that the lung pushes out between the ribs1 thus pressing against the ribs on the inner and the lateral sides4 ,the gizzard is back of the liver1 to the left side of the abdominal cavity1 and beneath and in front of the duodenal loop4 ,the small intestine from this side is above the gizzard4 ,supero-anterior to the gizzard is the blind end of the ccum4 ,the pancreas is within the duodenal loop4 ,illustration3 ,,fig4 #da4--,transverse section through the body of a hen at #ab1 ,fig4 #cc4 ,r1 ,right side4 ,l1 ,left side4 #a1 ,spinal cord4 #b1 ,esophagus4 #c1 ,inferior larynx4 #d1 ,base of the heart4 #e1 ,aorta4 #f1 ,vena cava4 #g1 ,lungs4 #h1 ,skin4 #i1 ,pectoral muscles4 ,figure #cd shows the viscera from the right side after the removal of the right abdominal and the right thoracic wall4 ,the base of the heart is in front of the right lobe of the liver4 ,above these the right lung occupies the upper part of the thoracic cavity as in the preceding illustration4 ,just back of this is the anterior lobe of the kidney4 ,the gall-bladder is observed at ,no4 #i on the right lobe of the liver4 ,just inferior to a longitudinal central line is the duodenal loop1 between the limbs of which is seen the pancreas4 ,above this loop the cca are located4 ,the gizzard is not visible from the right side2 on this side posterior to the liver is the small intestine4 ,superior to this at ,no4 #g the rectum4 ,the relative position of the visceral organs in the median line is observed in ,fig4 #ce4 ,no4 #a of this figure shows the stump of the first portion of the esophagus1 and ,no4 #b1 the left wall of the crop4 ,following this1 and located just below the vertebr is the second portion of the esophagus4 ,the major portion of the crop is located on the right side4 ,illustration3 ,,fig4 #db4--,transverse section through the body of a hen at #aa1 ,fig4 #cc4 ,r1 ,right side4 ,l1 ,left side4 #a1 ,spinal cord4 #b1 ,vertebra4 #c1 ,spinous process of vertebra4 #d1 ,lungs4 #e1 ,esophagus4 #f1 ,pericardial sac4 #g1 ,sectioned surface of heart4 #h1 ,auricle of heart4 #i1 ,blood clot in right auricle4 #aj1 ,section of sternum4 #aa1 ,pectoral muscles4 ,it will be noted that the second portion of the esophagus passes over the base of the heart and the superior part of the liver1 and then terminates in the proventriculus4 ,the proventriculus extends downward and empties into the gizzard4 ,this organ lies antero-laterally to the gizzard1 supero-posterior to the liver1 and to the left of the spleen4 ,the spleen lies in a triangle formed by the liver1 the proventriculus1 and the gizzard4 ,the heart is noted to lie supero-anterior to the liver1 and between the anterior portion of the fissure formed by the right and the left lobe4 ,the ovary is located back of the diaphragm at the anterior end of the kidney and below the inferior surface of the bodies of the vertebr4 ,the bulk of the floating portion of the small intestine is located above the gizzard4 ,illustration3 ,,fig4 #dc4--,transverse section through the body of a hen at #ac1 ,fig4 #cd4 ,r1 ,right side4 ,l1 ,left side4 #a1 ,spinal cord4 #b1 ,body of vertebra4 #c1 ,superior spinous process of vertebra4 #d1 ,lungs4 #e1 ,esophagus4 #f1 ,heart4 #g1 ,right and left lobes of liver4 #h1 ,sternum4 #i1 ,skin4 #aj1 ,pectoral muscles4 ,a transverse anterior section of a normal laying hen is shown in ,fig4 #ci1 the section being made at #ae of ,fig4 #cd4 ,at this point the esophagus lies centrally and above the trachea4 ,figure #dj shows a transverse anterior section through the thoracic region at #ad of ,fig4 #cd4 ,at this point the esophagus is slightly to the right of and is superior to the trachea4 ,at this level the apex of the lung is sectioned4 ,this is in the region of the cervical air-sac4 ,figure #da shows a posterior section at #ab of ,fig4 #cc4 ,the esophagus here is above and to the right of the inferior larynx1 and directly below and between the lungs4 ,the inferior larynx is above the base of the heart4 ,figure #db shows a transverse anterior section made at #aa of ,fig4 #cc4 ,it shows that at this level the esophagus is centrally located and passes over the base of the heart4 ,the heart occupies the lower portion of the thorax and the lungs the upper4 ,figure #dc shows a photograph of a transverse anterior section of the body made at #ac of ,fig4 #cd4 ,at this level the apex of the heart lies within the anterior fissure of the liver4 ,the sectioned portion of the heart shows the lower portion of the ventricle4 ,illustration3 ,,fig4 #dd4--,transverse section through the body of a hen at #ab1 ,fig4 #cd4 ,r1 ,right side4 ,l1 ,left side4 #a1 ,spinal cord4 #b1 ,articular surface of vertebral segment4 #c1 ,end of rib4 #d1 ,lungs4 #e1 ,proventriculus4 #f1 ,liver showing ,glisson's capsule4 #g1 ,sternum4 #h1 ,pectoral muscles4 #i1 ,skin4 ,illustration3 ,,fig4 #de4--,transverse section through the body of a hen at #aj1 ,fig4 #cc4 ,r1 ,right side4 ,l1 ,left side4 #a1 ,spinal cord4 #b1 ,body of vertebra4 #c1 ,lungs4 #d1 ,ova4 #e1 ,proventriculus4 #f1 ,liver4 #g1 ,sternum4 #h1 ,skin4 #i1 ,pectoral muscles4 ,in this figure the lungs show1 on the sectioned surface1 the ends of some of the larger bronchi4 ,the esophagus is located above the heart4 ,showing the relations of the visceral organs back of the heart girdle1 photograph number #dd1 gives an anterior section made at #ab1 ,fig4 #cc4 ,the lungs are spread out occupying the posterior thoracic region and below at ,no4 #aj is the diaphragm4 ,the diaphragm does not appear to have that rigidity and firmness of position as in mammals4 ,it is rather rudimentary4 ,below the left lung and above the left lobe of the liver is the proventriculus4 ,note that the viscus is empty and that the mucous membrane is thrown into folds4 ,at this point the liver occupies much of the abdominal cavity4 ,figure #de is a view of an anterior section made at #aj1 ,fig4 #cc4 ,in this section the lungs are decreasing in caliber4 ,the liver occupies much of the space in the lower right abdominal quadrant1 and above and to the right is the ovary with many of the ova developing yolks4 ,below ,no4 #d which is a developing yolk1 is the proventriculus4 ,figure #df is a view of an anterior section made at #i1 ,fig4 #cc4 ,at this level are shown sectioned surfaces of the kidneys1 which lie on either side of the spinal column4 ,below the spinal column and occupying the left upper quadrant is the ovary containing ova in the process of developing yolks4 ,to the right is the sectioned surface of one of the cca and below this and on the right side is the sectioned ends of many of the loops of the floating portion of the small intestine4 ,occupying the left lower quadrant is the sectioned surface of the gizzard and on the abdominal floor and to the right of the gizzard1 the posterior end of the right lobe of the liver4 ,illustration3 ,,fig4 #df4--;,a transverse section through the body of a hen at #i1 ,fig4 #cc4 ,r1 ,right side4 ,l1 ,left side4 #a1 ,spinal cord4 #b1 ,vertebra4 #c1 ,kidneys4 #d1 ,ovary4 #e1 ,ccum4 #f1 ,small intestine4 #g1 ,gizzard4 #h1 ,right lobe of liver4 #i1 ,skin4 #aj1 ,pectoral muscles4 ,,the ,,relations ,,of ,,the ,,visceral ,,organs ,,of ,,the ,,baby ,,chick ,there is approximately #dg per cent4 of the yolk retained in the abdominal yolk sac of the baby chick at hatching4 ,figure #dg shows a photograph of a longitudinal section through a baby chick4 ,this figure shows all the posterior portion of the abdominal cavity occupied with abdominal yolk4 ,the abdominal viscera are pushed forward1 and as the yolk is gradually absorbed the visceral organs gradually occupy their normal position4 ,illustration3 ,,fig4 #dg4--;,an antero-posterior section through the body of a baby chick just hatched4 #a1 ,abdominal yolk sac4 #b1 ,gizzard4 #c1 ,liver4 #d1 ,heart4 #e1 ,intestines4 #f1 ,spinal cord4 #g1 ,cerebrum4 #h1 ,cerebellum4 #i1 ,fat in the post-occipital region4 #aj1 ,the thymus gland4 ,illustration3 ,,fig4 #dh4--,transverse sections of the body of a baby chick at hatching4 ,r1 ,right side4 ,l1 ,left side4 ,a4 ,a transverse section at ,a1 ,fig4 #ej4 #a1 ,spinal cord4 #b1 ,esophagus4 #c1 ,entrance to thorax4 #d1 ,stubs of the wings4 ,b4 ,a transverse section at ,b1 ,fig4 #ej4 #a1 ,spinal cord4 #b1 ,esophagus4 #c1 ,lungs4 #d1 ,heart4 ,c4 ,a transverse section through the body at ,c1 ,fig4 #ej4 #a1 ,spinal cord4 #b1 ,lungs4 #c1 ,esophagus4 #d1 ,liver4 #e1 ,heart4 ,d4 ,a transverse section at ,d1 ,fig4 #ej4 #a1 ,spinal cord4 #b1 ,proventriculus4 #c1 ,liver4 #d1 ,gizzard4 #e1 ,intestine4 #f1 ,kidneys4 #g1 ,gall-bladder4 ,illustration3 ,,fig4 #di4--,transverse section through the body of a baby chick4 ,e at ,e1 ,fig4 #ej4 #a1 ,spinal cord4 #b1 ,kidneys4 #c1 ,gizzard4 #d1 ,intestines4 #e1 ,unabsorbed yolk4 #f1 ,stubs of legs4 ,f4 ,a section at ,f1 ,fig4 #ej4 #a1 ,spinal cord4 #b1 ,kidneys4 #c1 ,intestine4 #d1 ,unabsorbed yolk4 ,g4 ,a section at ,g1 ,fig4 #ej4 #a1 ,anus4 #b1 ,umbilicus4 ,a section through this body ,fig4 #dg at ,a is shown in ,fig4 #dh1 ,a4 ,at this point the esophagus appears below the vertebral column4 ,figure #dh1 ,b1 a section through the body at ,fig4 #dg1 ,b1 shows the apex of the lungs4 ,in a median line and below the lungs is the esophagus4 ,note the mucous membrane thrown into folds4 ,here the heart is sectioned1 showing both auricles and both ventricles4 ,this is a view looking forward4 ,figure #dh1 ,c1 is a view of a posterior section made at ,fig4 #dg1 ,c4 ,it shows the same relations of the esophagus and lungs1 but shows at this level both the right and the left lobe of the liver4 ,between these lobes we note the sectioned apex of the heart4 ,figure #dh1 ,d shows a posterior section at ,fig4 #dg1 ,d4 ,at this level the kidneys are above and infero-laterally to the spinal column4 ,the intestines are below the kidneys2 and on the left side1 between the kidneys and left lobe of the liver1 and near the abdominal wall1 is the proventriculus4 ,occupying the major portion of the inferior abdominal cavity are the right and the left lobe of the liver1 and between these the anterior border of the gizzard4 ,note the gizzard sitting at an angle inclining toward the left side4 ,figure #di1 ,e shows a section at ,fig4 #dg1 ,e4 ,here the gizzard occupies the left lower abdominal quadrant4 ,to the right are the intestines2 and directly above the gizzard is a small portion of the anterior end of the abdominal yolk sac4 ,infero-laterally are the kidneys4 ,figure #di1 ,f1 shows the kidneys similarly located as in the preceding2 and just below is the rectum suspended by the mesentery4 ,the rest of the cavity is occupied by the abdominal yolk4 ,,the ,,uro-,,genital ,,system ,the uro-genital apparatus1 or apparatus uro-genitalis1 consists of two groups of organs3 the urinary and the genital4 ,the former elaborate and remove the chief excretory fluid1 the urine2 and the latter serve for the formation1 development1 and expulsion of the products of the reproductive glands4 ,,the ,,urinary ,,apparatus 7,fig4 #ej and ,fig4 #ea74 ,the urinary apparatus of the bird consists of two kidneys1 from each of which a ureter extends and empties into the cloaca4 ,the ,kidneys4 ,location4--,the kidneys are located in excavations in the pelvic roof4 ,they are related internally with the posterior aorta and vena cava1 supero-internally with the lumbo-sacral vertebr and superiorly and supero-externally with the ilium4 ,the abdominal visceral organs lie below the kidneys4 ,the kidneys are external to or above the peritoneum4 ,shape4--,in the fowl of average size the kidneys are #b inches long and are made up of three irregular lobes4 ,the anterior lobe is usually the largest and the middle the smallest4 ,the anterior border of the first lobe is located opposite the last true dorsal articulation4 ,the anterior lobe is called the anterior pelvic or ilio-lumbar lobe1 the middle the middle pelvic or ilio-sacral lobe1 and the posterior the posterior pelvic lobe4 ,structure4--,the whole kidney has a fine transparent covering4 ,the dark1 brownish-red parenchyme can be seen through this membrane4 ,it has a blood vascular system and a urinary tubular system4 ,the larger arteries1 the veins1 and the nerves pass between the lobules1 and the smaller vessels between the tubules4 ,these form fine network or plexuses4 ,the lymphatic vessels are very few1 and are mainly found on the surface4 ,the kidneys are pierced in their posterior third by the external iliac artery and at about its middle by the venous branches forming the posterior vena cava4 ,the lobes are made up of lobules1 which are plainly perceptible from the external surface4 ,each lobule is apparently a unit within itself4 ,it receives its blood supply from small branches of the renal artery and is made up of a cortical or peripheral portion which contains the glomerules 7,fig4 #eb1 ,a7 and a medullary portion1 which is made up of tubules1 or urinary canals1 arteries1 veins1 and nerves4 ,illustration3 ,,fig4 #ej4--,photograph showing spinal cord and relative positions of the kidney1 lung and heart4 #a1 ,heart4 #b1 ,lung4 ,note the indentations made by the ribs4 #c1 ,the anterior1 middle and posterior lobes of the kidney4 ,the lobules are plainly visible4 #d1 ,the lumbo-sacral segment of the spinal cord4 #e1 ,terminal cord filament4 #f1 ,the cervico-dorsal segment of the spinal cord4 #g1 ,the brachial nerve plexus4 #h and #i1 ,the lumbo-sacral plexus4 #h1 ,the ischiadic nerve4 #i1 ,the lumbar nerves4 ,the urinary canals are divided into two kinds1 namely1 the outer and the inner tubular systems4 ,the outer canals1 called the tubul uriniferi corticalis1 are very small in caliber and are located in the lobules4 ,the renal artery 7,fig4 #ec1 ,no4 ,b1 #c7 breaking up into arterioles in the kidney1 and finally reaching the cortical portion of the lobules1 form capillary plexuses in the shape of minute spheres1 which are the glomerules 7,fig4 #ec1 ,no4 ,c1 #c and ,b1 #e74 ,around each glomerule there is formed a capsule called ,bowman's capsule1 which is the beginning of the uriniferous tubule4 ,this entire mass is called the ,malpighian body1 or renal corpuscle4 ,this capsule then extends as the urinary1 or secreting tubule1 being at first constricted1 then convoluted1 and terminates into a second portion1 the descending limb of ,henle4 ,this portion of the tubule becomes constricted4 ,it then forms the loop of ,henle and ascends as the second portion1 or second limb of ,henle1 which is again of greater diameter4 ,the top of the secreting tubule is slightly wavy and empties into the collecting tubule along with many others4 ,these collecting tubules in turn merge into large tubules which finally empty into the ureter 7,fig4 #ec1 ,no4 #ad74 ,these collective bundles correspond to the pyramids of the kidneys of mammals4 ,illustration3 ,,fig4 #ea4--,the kidneys4 #a;a1 ,the posterior4 #a;b1 the middle and #a;c1 the anterior lobes of the kidney4 #b1 ,the posterior aorta4 #c1 ,the external iliac or crural artery4 #d1 ,the ischiadic artery4 #e1 ,the sacralis media artery4 #f1 ,the ureter which empties into the cloaca at #g4 #h1 ,the external iliac vein4 #i1 ,the internal iliac vein4 #aj1 ,the iliacus communis4 ,illustration3 ,,fig4 #eb4 ,a4 ,photomicrograph of a section of a kidney showing three lobules4 #a1 ,cortical portion of lobule showing glomeruli4 #b1 ,the central or medullary portion of the lobule4 #c1 ,the outer surface of the kidney4 ,b4 ,salts from the urine of a hen4 #a1 ,uric acid crystals4 #b4 ,sodium urate crystals4 ,illustration3 ,,fig4 #ec4--,the renal structure4 ,a4 #a1 ,capillary blood-vessel4 #b1 ,descending limb of ,henle4 #c1 ,collecting tubule4 #d1 ,ascending limb of ,henle4 ,b4 #a1 ,branch of renal artery4 #b1 ,the descending or medullary branch4 #c1 ,the ascending branch4 #d1 ,the arteriole taking part in the formation of the glomerule4 #e1 ,the glomerule4 #f1 ,bowman's capsule4 #g1 ,blood-vessel extending from the glomerule4 #h1 ,the vein of the medullary part of the lobule4 #i1 ,the neck4 #aj1 ,the convoluted tubule4 #aa1 ,the descending limb of ,henle4 #ab1 ,henle's loop4 #ac1 ,the ascending loop of ,henle4 #ad1 ,the collecting tubule4 ,c4 #a1 ,section through a convoluted tubule4 #b1 ,bowman's capsule4 #c1 ,the glomerule4 ,the neck of the uriniferous tubule as it emerges from ,bowman's capsule is short and narrow and is lined with a few cuboidal cells4 ,toward the glomerular end the cells are of a transitional form gradually merging into the flat squamous type peculiar to ,bowman's capsule4 ,the first convoluted tubule is lined with irregular cuboidal or pyramidal epithelial cells4 ,the descending limb of ,henle's loop is narrow and is lined with a simple layer of flat epithelial cells4 ,in the loop the epithelium changes from the flat type in the descending limb to the cuboidal in the ascending limb4 ,the ascending limb of ,henle's loop again becomes broader and is lined with low cuboidal cells4 ,the second convoluted1 or tortuous1 tubule is lined with low cuboidal cells as are also the collecting tubules4 ,the collecting tubules originate from every part of the internal substance of the lobules1 and extending to the gyrations1 uniting in the pinniform structure and traversing to the margin of the lobules1 following along the uneven surface1 infero-laterally and toward the median body line1 finally empty into the ureter4 ,there are many arterial branches given off from the arteria renalis4 ,the arteries which supply the kidneys are given off from the posterior aorta and ischiadic artery4 ,as soon as these arteries enter the kidney they break up into two systems4 ,one system supplies the kidney substance with nourishment in the form of nutrient blood2 the second system supplies the glomerules with what may be considered functional blood 7,gadow74 ,the second system of arteries branches into the small arteria interlobularis1 which pass between the lobules of the kidneys where they give off side branches which penetrate the cortical portion of the lobules and form the capillary plexus1 the glomerule4 ,the arteriole that enters into the structure of the glomerule is lined with endothelial cells and is surrounded by a few muscle fibers and a fine network of connective tissue4 ,the vessel that carries the blood away is similarly constructed4 ,function4--,in the glomerules the liquid portion of the urine is filtered out of the blood1 which urine flows through the uriniferous tubules and passes from the kidney through the ureter4 ,in the cubical cells are extracted the solid portions of the urine which also pass through the tubules with the liquid4 ,the urinary secretion1 as found in the ureter1 does not contain much liquid1 but1 on the contrary1 is made up of a pasty material consisting of salts which are1 for the most part1 uric acid crystals and sodium urate 7,fig4 #eb1 ,b74 ,this material becomes hard1 like cement1 soon after being exposed to the atmosphere4 ,this secretion may be noted as a whitish pasty material on the outer parts of the feces1 or droppings1 voided by the birds4 ,the ,ureter4 ,location4--,the ureter extends along the inferior surface of the kidney4 ,it has its origin near the anterior extremity of the kidney1 and passing posteriorly the entire length of the kidney receives tributary collecting tubules1 and terminates in the upper wall of the cloaca in the urodeumal portion4 ,shape4--,the ureter gradually enlarges in diameter until it reaches the posterior border of the kidney1 and then maintains about the same caliber throughout the rest of its course4 ,structure4--,the ureter wall is made up of three coats as follows3 mucous1 muscular and fibrous4 ,function4--,the ureters serve as a passage way for the urine from the kidneys to the cloaca4 ,,the ,,male ,,generative ,,organs 7,fig4 #ed7 ,the male generative organs in the fowl consist of two testicles and an excretory apparatus1 the vas deferens1 for each4 ,the ,testicles4 ,location4--,the testicles are located in the sublumbar region of the abdominal cavity1 behind the lungs1 below the anterior extremity of the kidneys1 and opposite the last three ribs4 ,illustration3 ,,fig4 #ed4--,the pelvic organs of a cockerel4 ,a1 ,testes4 ,b1 ,rectum4 ,c1 ,cloaca4 ,d1 ,vas deferens4 ,e1 ,kidney4 ,f1 ,adrenal gland4 ,g1 ,lungs4 ,h1 ,ureter4 ,shape4--,the testicles are ellipsoid in shape2 their size varies with the different species of birds4 ,the two in the same bird are usually of the same size1 though one testicle may be slightly larger than the other4 ,in a summary of a large number of weights of the testicles of ten months old cockerels1 the average weight was #j4jba pound each4 ,the average measurements were #b inches in the major diameter and #a inch in the minor diameter4 ,in the cockerel before sexual maturity1 which is denoted by the male bird's crowing1 the testicles are very small4 ,they resemble1 in shape1 a navy bean and are yellowish-white in color4 ,structure4--,the testicle is surrounded by a thin fibrous capsule1 which1 in the mature cock1 is very vascular4 ,this capsule sends into the interior of the gland1 septa which form the framework1 or supporting structure4 ,this framework forms the spaces in which are located the glandular substance4 ,the glandular portion consists of the tubuli seminiferi1 which are lined with cubical cells4 ,the framework supporting these tubules gives passage to arterial branches of the spermatic artery1 which furnish an abundant blood supply2 the framework also supports the veins returning the blood from the testicle4 ,the seminiferous tubules end in blind extremities in the epididymus or globus minor1 and unite in the seminiferous canals4 ,all arteries1 veins1 lymphatics1 and seminiferous tubules enter or leave through the globus minor at the attached portion of the testicle4 ,the epididymis is made up largely of convoluted tubules which are the continuation of the secreting tubules of the globus major4 ,the walls of the tubules of the globus minor become thicker and are provided with smooth muscle cells in addition to the connective tissue and endothelial lining4 ,the convoluted tubules empty into the vas deferens4 ,the epididymus is covered by the fibrous capsule2 which corresponds to the tunica albuginea of mammals and may be considered as a reflection or modification of the visceral peritoneum4 ,the substance of the testicle is very soft2 in fact1 it may be said to be of the consistency of encephaloid material4 ,it is made up of secreting tubules in which are found the spermatozoa2 it also contains cells which produce an internal secretion1 or hormone4 ,there is also produced some fluid in which the spermatozoa float1 the whole material manufactured constituting the semen4 ,the spermatozoa of the fowl are provided with long cylindrical bodies1 which may be straight or wavy 7,fig4 #ee1 ,a74 ,the body of the spermatozoon is obtuse anteriorly1 and posteriorly1 tapers into a filimentary tail1 or flagellum1 of varying length1 by the aid of which the spermatozoon moves about in the fluid4 ,the histological structure of the testicles of the baby chick at hatching is approximately one-half white fibrous connective tissue4 ,the seminal tubules are small and widely distributed among the connective tissue4 ,the cells of these tubules possess rather large nuclei1 round in shape1 with linin network and chromatin granules1 typical of resting germ cells4 ,as the bird develops the testicles grow1 the seminal tubules become larger1 and the amount of connective tissue correspondingly less4 ,illustration3 ,,fig4 #ee4 ,a4 ,spermatozoa of a cock4 a1 ,the spermatozoa4 b1 ,the head4 c1 ,the tail4 ,b4 ,the oviduct of a hen removed4 ,a1 ,the oviduct4 ,b1 ,the superior ligament4 ,c1 ,the inferior ligament4 ,note the oviduct thrown in folds and the anastomosing blood-vessels4 ,in addition to the tubules1 the spermatogenic cells1 and the connective tissue1 there is also in the testicles more or less fat4 ,there is a small amount of connective tissue between the seminiferous tubules1 in which locations there are also clusters of polyhedral cells1 with round nuclei1 others are the interstitial cells4 ,the ,vas ,deferens 7,fig4 #ed1 ,d74 ,location and ,shape4--,extending from the epididymus1 is the vas deferens which runs backward on the infero-internal surface of the kidney and to the outside of the ureter4 ,it is very tortuous passing on the infero-lateral surface of the kidney in company with the ureter and becoming somewhat expanded posteriorly it terminates in the upper wall of the cloaca in a rather small papilla located in the uro-genital portion of the cloaca anterior to the mouth of the ureter4 ,this papilla is the organ of copulation and in ducks is very large1 and spirally elongated1 and retractile forming a kind of penis4 ,the papilla is traversed by a furrow on the upper surface through which the semen flows4 ,structure4--,the vas deferens is covered and supported by the peritoneum4 ,its wall is made up of a fibrous structure in which may be found smooth muscle fibers4 ,the wall does not possess glands4 ,it is lined with columnar epithelium4 ,the posterior end is expanded and terminates into a papilla4 ,the base of the papilla is surrounded by a plexus of arteries and veins1 which serve as an erectile organ during the venereal orgasm1 when the fossa of the turgid papilla is everted1 and the semen brought into contact with the similarly everted orifice of the oviduct of the female1 along which the spermatozoa pass by undulatory movements of their ciliary appendage1 or tail4 ,,the ,,female ,,generative ,,organs 7,fig4 #ef7 ,the female generative organs consist of one ovary and an oviduct4 ,location4--,the ovary is located similarly to the testicles of the male bird1 in the sublumbar region of the abdominal cavity1 just at the anterior end of the kidneys1 posterior to the lungs1 and slightly to the left of the center4 ,shape4--,in the pullet the ovarian mass appears somewhat like a bunch of grapes1 being made up of from #cejj to #dejj small1 whitish spheres1 which represent the undeveloped ova1 and which in the active state are developed1 one by one1 into yolks with their blastoderms4 ,from the blastoderm the fetus may later be developed4 ,in the active ovary of the laying hen the ovarian mass is of considerable size1 as it contains ova in different stages of development4 ,only one ovum is completely developed at a time1 though occasionally there may be only a few hours between the maturity of successive ova4 ,the ova receives nourishment from the blood-vessels of the capsule1 which vessels are branches of the ovarian artery4 ,illustration3 ,,fig4 #ef4--;,functionating female generative organs of a hen4 #a1 ,ova in process of formation of yolk4 #b1 ,stigmal line at which point the capsule ruptures when ovum is mature4 #c1 ,the funnel end of the oviduct4 #d1 ,the oviduct torn loose and laid to one side1 the albumin-secreting portion4 #e1 ,the shell membrane secreting portion4 #f1 ,the albumin4 #g1 ,the yolk4 #h1 ,the shell-secreting portion4 #i1 ,the cloaca4 #aj1 ,the rectum4 ,structure4--,the ovary contains very vascular cellulofibrous tissue4 ,the ovum as it develops is attached to the ovarian body by means of a delicate white fibrous pedicle4 ,when the yolk is mature it escapes from the enveloping fibrous capsule by a cleavage of the capsule4 ,the cleavage line is called the stigmen 7,fig4 #ef1 ,no4 #b74 ,the yolk is surrounded by a very delicate membrane called the vitelline membrane4 ,the empty sac now shrinks and finally disappears4 ,the ,egg4--,the principal divisions of the egg are the yolk1 the albumin outside of the yolk content1 the shell membranes and the shell 7,fig4 #eh74 ,as stated1 the yolk is formed in the ovary1 leaving the other three portions to be formed in the oviduct4 ,illustration3 ,,fig4 #eg4--,section through the ovary of the hen4 a1 ,the ova4 d1 ,an ovum beginning to receive deposits of yolk material4 c1 ,ova farther advanced in yolk formation4 ,the albumin may be subdivided into1 first1 a thin layer of albumin lying close around the yolk2 second1 a thick layer of albumin lying at the outer periphery2 and third1 a modification of the albumin called the chalaz4 ,the chalaz are twisted1 dense cord-like structures at either pole of the yolk1 one end of which is adherent to the vitelline membrane and the other to the inner membrane surrounding the albumin4 ,the chalaz thus act as stays to this structure1 which is carrying a delicate burden1 the blastoderm4 ,the shell membrane consists of two layers1 an inner delicate1 and an outer thicker layer4 ,when the egg is just laid these two membranes are in all parts closely adherent to each other1 and the egg content completely fills the shell cavity4 ,as soon as the content cools there is a slight contraction2 the two shell membranes separate at the large end of the egg1 forming an air cell which gradually enlarges as the evaporation of liquid through the pores of the shell takes place4 ,illustration3 ,,fig4 #eh4--;,a diagram of the parts of the egg4 a1 ,the blastoderm4 b1 ,the shell4 c1 ,the outer shell membrane4 d1 ,the inner shell membrane4 e1 ,the air-sac at the large end of the egg4 f1 ,the albumin4 g1 ,the chalaza4 h1 ,the yellow layers of yolk4 i1 ,the white layers of yolk4 k1 ,the flask-shaped portion of white yolk4 l1 ,the vitelline membrane4 ,the shell consists of several layers4 ,three are easily distinguishable3 first1 an inner mammillary layer1 consisting of minute conical deposits of calcareous material2 second1 a middle spongy layer1 composed of a thick network of fibers2 third1 an outer delicate1 cuticle-like structure4 ,in certain breeds of poultry a pigment may be added2 for example1 in ducks a pea green1 in turkeys a spotted brownish material1 and in fowls pink and various shades of brown4 ,the egg shell is porous to admit the free exchange of air during the process of incubation4 ,an average sized hen egg weighs about #b ounces1 of which #aa per cent4 is shell1 #cb per cent4 yolk1 and #eg per cent4 white4 ,the principal chemical constituents of the egg are as follows3 ash1 or mineral matter1 #i per cent42 fat1 or hydrocarbon1 #i4c per cent42 proteids1 or nitrogenous matter1 #aa4i per cent42 and water1 #fe4e per cent4 ,there is apparently no constant proportion of weight between the yolk and albumin4 ,there is also a variation in the weight of the shell due to its variation in thickness4 ,in an examination of ten eggs of average size1 the yolk constituted #ca per cent4 of the total weight of the egg4 ,the following is the result of the analysis of twelve eggs of average size4 ,this analysis included the shell and all other parts taken together4#f ,footnote #f3 ,the analysis was made by ,d4 ,m4 ,mc,carty1 chemist1 ,animal ,industry ,division1 ,north ,carolina ,experiment ,station4 ,moisture #fd4be per cent4 ,dry matter #ce4ge per cent4 -------------------------------- #ajj4jj per cent4 ,parts per hundred including shell ,protein #aj4bejj ,fat #aj4fbjj ,phosphorus 4#cjbj ,calcium 4#fjhj ,magnesium 4#jihe ,iron 4#jajc ,sulphur 4#ciej ,chlorine 4#aejf ,potassium 4#jajc ,sodium 4#bjjj ,the ,oviduct4--,the three separate and distinct portions of the egg1 albumin1 shell membranes1 and the shell1 are constructed in different parts of the oviduct4 ,location4--,the oviduct of the hen extends along the left side of the bodies of the vertebr1 and the roof of the pelvic cavity and lies dorsal to the abdominal air-sac4 ,it extends from the posterior border of the ovary and empties into the cloaca 7,fig4 #ef1 ,no4 #c and #h7 through a transverse slit4 ,shape4--,in a well-developed ,plymouth ,rock pullet1 but one whose reproductive organs have never become active1 the oviduct is about #d inches long2 in the fully developed and active state it is from #ah to #bj inches long1 and in a collapsed state about inch in diameter4 ,it is held in position by two ligaments1 a dorsal and a ventral 7,fig4 #ee1 ,b7 to be described later4 ,the oviduct is tortuous in its course1 forming three principle convolutions before reaching the cloaca1 and like the ovarian mass1 in its active state1 pushes the abdominal viscera downward and toward the right side4 ,structure4--,the oviduct consists of three coats3 first1 the serous1 located on the outside1 which is a reflection of the peritoneum2 second1 the muscular middle tunic2 third1 the mucous coat1 which in a resting state is thrown into folds4 ,illustration3 ,,fig4 #ei4--,the active oviduct of a hen laid open4 #a1 ,the ovary4 #b1 ,the funnel4 #c1 ,the albumin-secreting portion4 #d1 ,the isthmus4 #e1 ,the shellgland portion4 #f1 ,the vagina4 #g1 ,the superior ligament4 #h1 ,the inferior ligament4 ,parts of the ,oviduct4--,the parts of the oviduct are as follows3 the funnel1 the albumin-secreting portion1 the isthmus1 the shell-gland portion1 or uterus1 and the vagina 7,fig4 #ei74 ,illustration3 ,,fig4 #fj4--,the mucous lining of the oviduct4 ,a4 ,transverse section of the oviduct wall in the region of the neck of the funnel showing primary and secondary folding of the epithelium 7after ,surface74 ,b4 ,showing the type of gland cells of the funnel region4 ,c4 ,transverse section through the wall of the uterus showing the deep folds4 ,d4 ,section from the albumin-secreting portion showing the opening of a tubular gland and also showing the character of the cells4 ,the funnel is the trumpet-shaped portion1 the ostium tub abdominale1 whose mouth or fimbriated opening faces the ovary1 and lies ventrally to receive the ovum1 or yolk1 as it is discharged from the ovary4 ,its thin wall1 expanded in the anterior portion1 is provided with fimbri-like projections4 ,this funnel-shaped portion soon converges to form a constricted portion4 ,this portion of the active oviduct is from #c to #d centimeters long4 ,the mucous membrane occurs in folds forming low longitudinal spiral ridges 7,fig4 #fj1 ,a74 ,the fimbri are continuous with the dorsal and the ventral ligament of the oviduct2 and from this point1 where the ridges of the mucous membrane are almost nil1 they gradually increase in height as they extend down the tube4 ,these ridges are continued in those of the second1 or albumin-secreting portion 7,fig4 #fj1 ,d74 ,at this point they increase in height very rapidly4 ,here the bundles of muscular fibers of the middle coat are thin and distributed among bundles of connective tissue4 ,the muscular fibers consist of two layers1 an outer longitudinal and an inner circular4 ,at places in this portion the inner bundles may be noted to extend longitudinally4 ,in embryological development the epithelial layer has an origin different from the outer layers of the oviduct4 ,in the fetal development the ,mllerian duct arises as a thickening along the ,wolffian body just ventral to the gonad4 ,this ,mllerian duct is at first a solid cord of cells4 ,it later develops a lumen1 and grows posteriorly until it connects with the cloaca4 ,at the time of this posterior growth1 mesenchyme cells migrate in from the surrounding tissue and form a layer about the duct4 ,from this layer of mesenchyme cells there are developed the outer layers of the oviduct1 which layers later develop the muscular structure and the connective tissue4 ,the epithelium and its derivatives1 which represent the glandular structures1 are formed from the walls of the old ,mllerian duct4 ,thus the two sets of tissues1 having different origins1 likewise have different functions4 ,the epithelium is concerned entirely with secretion1 and the derivatives of the mesenchyme are concerned with supporting and muscular function4 ,illustration3 ,,fig4 #fj4 ,a4--,the mucous lining of the oviduct4 ,e4 ,section of the epithelium from the vagina showing unicellular glands4 ,f4 ,a section from the isthmus showing opening of a tubule4 ,to summarize1 six layers of tissue occur in the funnel region1 namely1 an outer serous covering1 an outer longitudinal muscular layer1 a layer of connective tissue1 an inner circular layer1 a second layer of connective tissue1 and an inner mucous layer4 ,the mucous layer is made up of glands1 as follows4 ,the unicellular glands occur between the ciliated cells of the epithelium4 ,these glands are found only in the posterior half of this division of the oviduct4 ,the glandular grooves are made up of an accumulation of gland cells at the bottom of the grooves between the secondary folds of the epithelium4 ,these are found in all parts of this division except the extreme posterior part4 ,in the posterior part we find the third type of glands1 the tubular variety4 ,the second division of the oviduct1 as stated above1 is the albumin-secreting portion4 ,the funnel division gradually merges into the second portion4 ,these two portions are distinguishable from each other4 ,the walls of the albumin-secreting portion are much thicker and the longitudinal ridges are higher4 ,this section is the longest of the five divisions1 measuring from #dj to #db centimeters in length1 or more than half the length of the oviduct4 ,the albumin division terminates rather abruptly into the third division1 the isthmus 7,fig4 #ei1 ,a74 ,it is probable that the secretion of albumin is not confined to the cells of the second division2 yet we are safe in saying that the major portion is formed here4 ,the folds of mucous membrane in this division are thicker and higher than in the funnel1 due to their containing cells of the high columnar type1 and to the fuller development of the glands which are of the tubular variety4 ,the muscular layer is heavier1 and therefore the muscular power to force along the tubes' contents is greater4 ,in the formation of the mucous folds we find1 in transverse sections1 that the central core is made up of connective tissue which carries blood-vessels and nerve filaments1 as in other similar glandular structure4 ,the epithelium contains glandular cells of two varieties1 namely1 the ciliated1 columnar variety1 and the unicellular1 goblet variety 7,fig4 #cf1 ,no4 ,b1 #b74 ,these two kinds of glandular cells are rather evenly distributed throughout the epithelium of this section of the oviduct4 ,the unicellular gland cells are more numerous at the mouths of the ducts leading from the tubular glands4 ,the nuclei of the ciliated cells are oval and lie near the middle of the cells or a trifle toward the base from the middle4 ,the protoplasm of the cells is finely granular4 ,strong cilia in considerable number surmount each cell4 ,in some cases the goblet or mucous cells have pushed apart the ciliated cells1 and their prolongations extend farther than the surface of the ciliated cells4 ,the nuclei of the goblet cells are round1 and lie nearer the proximal end than those of the ciliated cells4 ,the third division of the oviduct1 the isthmus1 continues from the albumin-secreting portion and terminates in the expanded portion called by some anatomists1 the uterus4 ,toward the posterior end of the albumin-secreting portion the longitudinal folds of mucous membrane become lower1 making1 at the juncture of this and the isthmus1 a clear fine of demarcation4 ,for a distance of #b or #c centimeters the folds are low1 after which they gradually become higher1 but never reach the height or thickness of those in the albumin-secreting portion4 ,the clear-cut line between the albumin-secreting portion and the isthmus is partly due to a zone in which the long tubular glands are lacking4 ,the core of the folds of mucous membrane in this zone contain much more connective tissue4 ,the cells are both ciliated and unicellular4 ,the rest of the histological structure of the isthmus is the same as that of the albumin-secreting portion4 ,the function of the isthmus is to secrete1 or to form1 the shell membrane1 the membrana testacea4 ,the fourth division of the oviduct is the uterus1 or the shell-gland portion 7,fig4 #fj1 ,c74 ,there is no clear line of demarcation between the isthmus and shell-gland portion1 the walls gradually expanding4 ,in this region the folds of mucous membrane become leaf-like and of considerable length1 extending into the lumen1 thus affording a greater cellular surface4 ,the same coats of the duct are present here as in other parts2 but the outer longitudinal muscular layer is thicker and possesses more strength4 ,the quantity of connective tissue is about the same4 ,the glands are of a tubular type and the same two varieties of epithelial cells are found here as elsewhere1 namely1 the ciliated high columnar and the unicellular mucous variety4 ,in the active glandular cells of the shell-forming region the nuclei are small1 dark staining1 and lie toward the center of the cell4 ,the chromatin granules and nucleoli take on a comparatively deep basic stain1 but they do not show the intense stain found in the albumin and the isthmus region4 ,the cytoplasm of the uterine tubular glands does not present as heavy a granular appearance as that of the albumin portion4 ,these cells are diffusely granular1 the granules appearing of one size and taking the stain faintly4 ,the function of this portion is to secrete1 or form1 the hard calcareous covering which has been described at the beginning of this section4 ,the fifth division of the oviduct is the vagina4 ,there is located1 at the juncture of the shell-gland portion with the vagina1 a strong sphincter muscle4 ,the vagina is that constricted portion of the oviduct extending from this muscle to the cloaca4 ,the mucous membrane forms low narrow folds with secondary folds1 which appear continuous with those of the shell-gland portion4 ,the core of these folds is composed of connective tissue4 ,the vagina in the hen of average size measures from #ab to #ac centimeters long 7,surface74 ,the inner or circular muscular layer is well developed2 it is much thicker than in any other part of the oviduct4 ,this extra development gives the power necessary to successfully expel the egg4 ,the outer longitudinal layer is not so well developed2 its bundles are scattered throughout the connective-tissue layers4 ,the egg is caused to move along in the oviduct by a successive series of contractions of the circular muscular fibers posterior to it4 ,there are no tubular glands in this portion1 but a simple layer of high ciliated columnar epithelium1 and some goblet1 or mucous cells4 ,the cells on the surface generally are long and slender2 in the grooves between the mucous folds the cells are shortest1 reaching their greatest length at the tops of the folds4 ,the function of the vagina is the secretion1 or formation1 of the outer shell cuticle commonly called the bloom1 and also in certain breeds1 as indicated above1 the tint4 ,the cloaca furnishes a passage way from the vagina to the external world by way of the anus4 ,the walls of the cloaca contain glands4 ,the ,ligaments of the ,oviduct4--,it is held in position by two ligaments1 one dorsal and one ventral4 ,the dorsal ligament of the oviduct is formed by a double layer of peritoneum with a very small amount of connective tissue interposed4 ,the peritoneum is also reflected over the oviduct4 ,the ventral ligament of the oviduct is narrower than the dorsal1 but is similarly constructed4 ,both ligaments are rather veil-like in appearance4 ,during the first four or five months of the growth of the young female fowl the development of the oviduct and its ligaments is in proportion to that of the body4 ,with the elongation that takes place about the time of functionation1 as described above1 the ligaments enlarge in proportion to the enlargements of the oviduct4 ,the dorsal ligament maintains a line of attachment to the body wall from the caudal end of the body cavity to the fourth thoracic rib4 ,the ventral ligament elongates only slightly during this developing period4 ,it becomes thicker and stronger and early develops a muscular coat4 ,it also grows in width except at the caudal end4 ,at this point the ligament is simply a mass of muscular tissue of the smooth or involuntary type4 ,these ligaments are fan-shaped4 ,the muscle fibers of the dorsal ligament of the laying hen1 have their origin in a line near the medial side of the dorsal margin4 ,at this point the bundles of fibers are quite thick1 but are spread out thinly toward the margin of the oviduct4 ,frequent anastomoses are noted4 ,the muscular fibers become continuous with the circular ones of the oviduct4 ,the ventral ligament of the oviduct of the laying hen is largely a muscular cord #c to #f centimeters in diameter4 ,the caudal end is thicker1 becoming gradually thinner toward the anterior portion4 ,the bundles of muscular fibers extend toward the oviduct blending with the circular fibers of that viscus4 ,the ligaments terminate anteriorly in such a manner that they aid in forming the serous ovarian pocket1 which guides the yolk into the fimbriated portion1 or funnel1 of the oviduct4 ,the walls of the ovarian pocket are formed by the left abdominal air-sac1 a part of the intestine1 and the mesentery4 ,the dorsal portion is formed by the roof of the abdominal cavity1 and the ventral portion is formed by the dorsal wall of the air-sac4 ,the medial1 the anterior1 and the lateral limit of the pocket are formed by a fusion of the wall of the air-sac to the mesentery and to the body wall4 ,posteriorly1 the wall consists of the transverse part of the small intestine and the caudal portion of the left ccum with their attached mesentery4 ,,the ,,ductless ,,glands ,these glands do not possess excretory ducts4 ,they furnish materials which are added to the blood or lymph as it passes through them4 ,the material from each gland is known as an internal secretion1 or hormone4 ,some of these secretions are powerful materials and influence profoundly the body nutrition4 ,the ductless glands are usually given as follows3 the spleen1 the lymph glands1 the pineal gland1 the pituitary body1 the thyroid gland1 the thymus gland1 the adrenal glands1 and the parathyroids4 ,the spleen1 the pituitary1 the pineal1 and the lymph glands are described in other sections4 ,the ,thyroid ,gland 7,fig4 #ba1 ,no4 #af74 ,location4--,the thyroid gland lies on the ventral side of the carotis communis at a point where the carotis communis touches the jugular vein1 which is about the point of origin of the vertebral artery4 ,shape4--,the thyroid gland is small1 oval or somewhat roundish1 and red or rose-colored4 ,structure4--,the thyroid gland has a fibrous capsule1 which sends into the interior septa which divide it into acini4 ,these acini are closed and contain a fluid4 ,the thyroid is a ductless gland4 ,short arteries from the carotis enter this gland1 and some large veins connect it with the jugular vein4 ,the lymph vessels which lie along the neck are closely connected with it and receive twigs from the gland4 ,the minute lymphatic capillary endings are found in its septa and in its capsule4 ,the acini are lined with a single or a double row of cuboidal secreting cells4 ,there are two kinds of cells1 namely1 secreting and resting cells4 ,the actively secreting cells secrete colloid4 ,the parathyroids consist of two small bodies attached to the lower pole of the thyroid4 ,the ,thymus ,gland 7,fig4 #dg1 ,no4 #aj74--,the thymus gland is an organ of fetal and early baby chickhood4 ,it soon undergoes retrogressive changes into fat and connective tissue4 ,it is of epithelial origin1 being formed in fetal life from the entodermal cells of the dorsal end of the throat fissure4 ,location4--,the thymus gland lies anterior to the thyroid1 the latter lying the deeper4 ,shape4--,the thyroid consists of two lobes1 which are united by connective tissue1 and appears as a loop-like acinous gland lying along the neck and near the region of the bronchi and the jugular veins with fibrous extensions toward the head4 ,structure4--,the gland lobes are divided into lobules1 which consist of a cortical and a medullary portion4 ,the cortex consists of nodules of compact lymphatic tissue similar to those found in the lymph glands4 ,these occupy the chambers formed by the septa of connective tissue4 ,in the medulla there are a number of spherical1 or oval bodies composed of concentrically arranged epithelial cells4 ,these are known as ,hassall's corpuscles1 and represent only the remains of the original glandular epithelium4 ,they are characteristic of the thymus gland4 ,the thymus appears to be a type of lymph organ4 ,lymph vessels are rare2 a few blood-vessels on the upper side form capillary nets4 ,the ,adrenal ,gland 7,fig4 #ed1 ,f74 ,location4--,the adrenal gland1 often called the suprarenal capsule1 lies just anterior to the front part of the anterior lobe of the kidney1 adjacent to the testicles in the male and to the ovary in the female4 ,it is loosely attached by connective tissue to the posterior aorta and to the vena cava4 ,shape4--,it is yellowish-brown or reddish-pink in color1 small1 and of irregular formation4 ,structure4--,the adrenal gland consists of a cortical and a medullary portion1 although these two parts are not distinctly marked4 ,the cortical portion has columns which extend deeply into the gland1 and the medullary portion sends columns into the cortical portion4 ,therefore1 the two substances1 lying side by side1 form a cord-like structure4 ,it is probable that the cortical portion is derived from the ingrowths of the peritoneum1 and the medullary cords from the sympathetic ganglion4 ,the cells are cylindrical or polygonal in shape1 with an eccentric substance between the columns4 ,the cords1 or columns1 form between them1 elongated channels which extend into the interior of the gland and end as blind or ccal extremities4 ,large ganglionic nerve cells belonging to the sympathetic system occur near the surface of the gland4 ,the blood-vessels are not well developed in the interior of the gland but are numerous and of good size in the outer parts4 ,lymph vessels are also present4 ,function4--,the adrenals are ductless glands4 ,they secrete an internal secretion1 or hormone1 which influences the tonus of the blood-vessels4 ,an extract from these glands is called adrenalin4 ,,the ,,respiratory ,,apparatus 7,figs4 #ej and #fa1 ,a7 ,owen says3 8,notwithstanding the extent and activities of the respiratory function in birds1 the organs subservient thereto manifest more of a reptilian than of the mammalian type of formation40 ,by the action of the respiratory organs certain chemical and physical changes take place in the blood4 ,the chief of these consists in absorption of oxygen from1 and giving off carbon dioxide to1 the atmospheric air1 the former changes being necessary for the elaboration of the fluid1 the latter for the elimination of a substance which1 if retained1 would prove injurious4 ,the organs of respiration are invariably adapted to the wants of the animal and the medium in which it lives4 ,in the bird1 which breathes through its nose1 the organs of respiration are nostrils1 nasal chambers1 pharynx1 superior larynx1 trachea1 inferior larynx1 bronchi1 bronchial tubes1 lungs1 and air-sacs4 ,the ,nostrils and the ,nasal ,chambers4--,the nostrils of the bird open externally by two small elliptical openings1 which pierce the upper mandible4 ,within each nasal chamber 7,fig4 #bf1 ,a7 are three turbinated lamin1 or turbinated bones4 ,the inferior one is a simple fold adhering to the lower and anterior part of the nasal septum4 ,the middle turbinated bone is the largest4 ,it is of infundibular form1 and adheres by its base to the septum and externally to the side wall of the nose4 ,it is convoluted with two and a half turns4 ,the superior bone1 of bell shape1 adheres superiorly to the frontal bone4 ,the internal turbinated bone extends toward the orbit2 the external terminates in a cul-de-sac behind the middle turbinal 7,fig4 #bf1 ,no4 ,a1 #a and #b1 and ,g74 ,the nostrils are separated by a partition which is partly bony and partly cartilaginous4 ,the posterior nares is represented by a long slit in the hard palate4 ,the ,pharynx and the ,superior ,larynx4--,a transverse row of horny1 filiform papill marks the anterior border of the pharynx1 where in other animals the soft palate1 or velum1 is located4 7,for further description of the pharynx see special chapter47 ,the supero-posterior border of the larynx1 at the juncture of the larynx and the esophageal margin1 is marked by a second transverse row of horny1 filiform papill1 which point backward4 ,there is no epiglottis4 ,the superior part of the larynx is pierced by an oval1 slit-like opening1 the glottis1 which is provided with two lips4 ,these when brought together1 tightly close the glottis so that nothing can fall through into the larynx in the act of deglutition4 ,the margin1 or rim1 of this opening is called the rami glottis4 ,the glottis is controlled by two pair of muscles4 ,the superior surface of the larynx is somewhat triangular with the apex directed forward4 ,a few delicate1 filiform papill are upon its surface4 ,the bird has1 as already indicated1 two larynxes1 the superior larynx located at the upper end of the trachea1 and the inferior larynx at the bifurcation of the trachea4 ,the inner surface of the superior larynx is smooth and does not contain vocal cords2 it is in these animals simply a passage for air4 ,it is joined to the trachea inferiorly by a ligament1 the crico-trachealis1 and lies at the base of the tongue supported by two cornua of the os hyoideum4 ,the cartilages forming the principal support of the superior larynx1 consist of four pieces1 as follows3 one unequal ventral piece1 two side pieces1 and one unequal dorsal piece4 ,the cartilaginous1 flat1 ventral cricoid1 early in the bird's life1 often becomes bony4 ,the side pieces are separated from it1 only exceptionally fusing with it4 ,the dorsal cricoid piece also often becomes bony4 ,the two arytenoid cartilages1 joined with the cricoid superiorly1 are three-sided1 and are united to each other in a sharp angle4 ,they form the superior opening of the superior larynx4 ,the ,trachea4--,the trachea is cylindrical and varies in length in different kinds of birds in accordance with the length of the neck4 ,it consists of from #ij to #abj cartilaginous rings1 complete with the exception of the two uppermost1 which rings are held together by intercartilaginous ligaments4 ,the tracheal rings are constructed of hyaline cartilage and the ligaments of fibrous tissue4 ,it is lined with a mucous membrane covered by columnar epithelium4 ,the trachea is a passage for air alone and terminates in the inferior larynx4 ,the ,inferior ,larynx4--,the inferior larynx1 called the true larynx because it is the organ of voice1 is located at the inferior end of the trachea and the superior ends of the bronchi4 ,by some anatomists this organ has been called the larynx broncho-trachealis4 ,the larynx is flattened laterally in fowls4 ,it contains two membranous folds1 which in the production of sound are caused to vibrate4 ,these folds are half-moon shaped elastic structures1 located in the bony1 arrowlike way1 intero-inferiorly4 ,these structures are called the membrana tympana interna4 ,in the duck this inferior larynx is represented by a drum-like cartilaginous and bony structure1 called the bulla tympaniformis4 ,this bulla is a resonant apparatus which serves to strengthen the voice4 ,in song birds there is a double glottis1 usually produced by a bony bar1 called the pessulus1 or os transversale1 which traverses the lower end of the trachea from front to rear4 ,it supports a thin membrane which ascends into the tracheal area1 and1 terminating there by a free concave margin1 is called the membrana semi-lunaris4 ,this is most developed in singing birds1 and being vibratile1 forms an important part of their trilling vocal apparatus4 ,the air passes on each side of the membrana semi-lunaris and its sustaining bone to and from the bronchi and lungs4 ,the last ring of the trachea usually expands as it descends1 with its fore and posterior parts produced1 and the lower lateral borders concave2 the extremities of the pessulus1 butts against the angle thus formed and expands to be attached1 also with the fore and posterior terminations of the first half ring of the bronchus1 strengthening and clamping together the upper part of the vocal framework4 ,the second bronchial half ring is flattened and curved with the convexity outward1 like the first1 but is more movable4 ,the third half ring is less curved and further separated from the second1 to the extremities of which its own are connected by a ligament1 and1 for the intervening extent1 by a membrane2 its inner surface supports the fibrous cord1 or fold1 which forms the outer lip of the glottis of that side2 it is capable of rotary movements on its axis1 and is an important agent in the modulation of the voice4 ,all these parts just described are bony4 ,the ,bronchi and the ,lungs4--,the bronchi1 two in number1 are provided with only incomplete cartilaginous rings4 ,they enter the inferior face of the lungs1 toward their anterior and middle thirds and break up into primary bronchi1 which give off at right angles1 secondary bronchi1 and these latter in turn give off tertiary branches4 ,illustration3 ,,fig4 #fa4--,the lung4 ,a4 ,the outer surface of one lung4 ,note the flattened oval shape4 ,it is not divided into lobes4 #a1 ,the bronchus4 #b1 ,primary tubules showing openings leading from the primary tubules to the secondary tubules4 #c1 ,openings of two of the large tubes into the diaphragmatic and abdominal air-sacs4 ,b4 ,sectioned surface of lung4 #a1 ,secondary tubules4 #b1 ,tertiary tubules4 #c1 ,interlacing capillaries and air cells4 ,c4 #a1 ,cavity of tubule4 #b1 ,its lining membrane supporting blood-vessels with large areol4 #c1 ,perforations in the membrane at the orifices of the lobular passage4 #d1 ,interlobular space containing the terminal branches of the pulmonary vessels supplying the capillary plexus1 #e1 to the meshes of which air gets access by the lobular passage4 ,the lungs occupy only about one-seventh of the thoracic space4 ,they are long1 flattened1 and oval1 extending along each side of the spine from the second dorsal vertebra to the anterior end of the kidneys1 and laterally to the juncture of the vertebral with the sternal portions of the ribs4 ,they present two faces1 a superior convex and an inferior concave2 two borders1 an external and an internal2 and two extremities1 an anterior and a posterior 7,fig4 #fa74 ,the convex surface is also called the dorsal1 costal1 or superior face4 ,it is moulded on the walls of the thorax and occupies a part of the intercostal space1 pushing the intercostal muscles outward4 ,when the surface of the lung is examined it is seen to be furrowed where the ribs pressed during life4 ,these furrows are as deep as the ribs are thick4 ,the sides of the lungs are covered with connective tissue which attaches them to the costal walls4 ,the concave1 or inferior1 face also called the diaphragmatic or visceral face is directed downward4 ,the diaphragm separates it from the abdominal viscera4 ,the surface is covered by connective tissue which closely attaches it to the diaphragm4 ,it is perforated by the five tubules which bring the posterior air-sac into communication with the lungs4 ,the borders of the lungs extend parallel to the long axis of the body4 ,the internal border is rectilinear1 thick1 and rounded4 ,the external border is convex1 thin1 and sharp4 ,the anterior extremity terminates in a sharp point which occupies a space formed by the ribs externally and the inferior spines internally4 ,the posterior extremity is somewhat rounded and extends as far back as the anterior border of the kidneys4 ,as soon as the bronchi enter the lungs they become broadened1 the cartilaginous rings disappear1 and they continue as membranous channels whose diameters gradually decrease1 as they extend backward1 to the point where they terminate in the ostium caudale1 at which point they are surrounded by a cartilaginous ring4 ,the ostium caudale brings the tubules into communication with the ventral air-sacs4 ,twelve air tubules have their origin from each common bronchus1 or trunk4 ,four are given off from the internal wall of the main bronchus by a series of openings arranged in a row4 ,seven are given off from the external wall by a second series similar to that of the first4 ,the twelfth extends from the inferior wall1 and immediately takes a course downward and outward and communicates with the posterior diaphragmatic air-sac4 ,this may be considered as the terminal branch of the trunk4 ,all of these secondary canals1 except the last1 pass toward the periphery of the lung4 ,they divide and subdivide at the periphery1 covering it with their ramifications4 ,the canals extending from the inner wall are distributed to the inferior face of the lung4 ,those extending from the outer wall are distributed to the outer face of the lung4 ,the first constitute the diaphragmatic and the second the costal bronchial tubes4 ,the four diaphragmatic bronchial tubes are numbered in the order in which they are given off4 ,the first is carried forward horizontally1 the second transversely inward1 the third obliquely inward and backward1 and the fourth directly backward4 ,they have1 by some anatomists1 been called the anterior1 the internal1 and the posterior diaphragmatic bronchial tubes4 ,there are two posterior diaphragmatic bronchial tubes2 the larger called the great posterior1 and the smaller1 which passes directly backward1 the small posterior4 ,the costal bronchial tubes1 seven in number1 are numbered from the front backward in the order they are given off4 ,parallel at their origin1 and side by side1 like pipes of an organ1 they soon spread out in fan-shape like the preceding4 ,they extend from their central origin to the periphery4 ,the first extends obliquely upward and inward to the anterior extremity of the lung4 ,all branches from this bronchus extend from its anterior wall4 ,the first branches are inflected to reach the external border of the lung4 ,the succeeding branches are directed forward and the last forward and inward4 ,they all meet those from the anterior diaphragmatic bronchus1 but do not anastomose with them4 ,the second1 the third1 and the fourth costal bronchi extend in a transverse manner and ramify on the inner border of the lung4 ,the fifth and the sixth are directed toward the posterior extremity of the lung4 ,the seventh1 very small1 reaches this extremity1 where it disappears4 ,the first costal bronchus is the largest2 those following it gradually become smaller4 ,at their points of origin they adhere closely to the ribs4 ,they are all imperforate1 which is a distinguishing feature from those occupying the opposite face4 ,the canaliculi or tertiary tubules given off by these secondary bronchial tubes do not differ greatly in caliber in the various parts4 ,they are given off at right angles from the pulmonary wall of each bronchus1 and extend perpendicularly into the lung substance4 ,thus we find three kinds of conduits1 the primary1 the secondary1 and the peripheral1 or tertiary4 ,the first are like the barbs of a feather on its shaft2 and the second and parenchymatous are implanted on the pulmonary walls of the first1 like the hairs of a brush on their common base4 ,thus instead of the branching of the bronchi being dichrotomous1 as in mammals1 it is piniform4 ,the canaliculi1 or finer tubules1 communicate with one another4 ,the inner microscopic appearance of the canaliculi indicate that they are divided into areola1 which gives them a cellular aspect4 ,these tertiary bronchi open on a dense labyrinth of blood capillaries 7,fig4 #fa1 ,c74 ,at this point the ciliated epithelial cells give way to simple squamous epithelium4 ,thus we find three kinds of bronchi1 or their ramifications1 as follows3 the primary1 the secondary1 and the tertiary4 ,the ,air-sacs 7,fig4 #fa1 ,a74--,the air-sacs are bladder-like structures consisting of a delicate cellulo-serous membrane1 an extension from the bronchial tubes1 in some places strengthened by an external envelope of elastic fibrous tissue4 ,long thin blood-vessels are distributed in the substance of these walls4 ,they are branches from vessels of the general circulation and not extensions from those of the lungs4 ,no lymphatics have been found in the air-sacs4 ,illustration3 ,,fig4 #fa1 ,a4--,diagram of air-sacs and their location4 #a1 ,the proximal end of the humerus4 #b1 ,the proximal end of the right clavicle4 #c1 ,the cervical air cell4 #d1 ,the right coracoid bone4 #e1 ,the anterior thoracic air cell4 #f1 ,the right side of the sternum4 #g1 ,the right side of the liver4 #h1 ,the peritoneum4 #i1 ,the right abdominal air cell4 #aj1 ,the coccyx4 #aa1 ,the proximal end of the right femur4 #ab1 ,the right supero-posterior air-sac4 #ac1 ,the right infero-posterior air-sac4 #ad1 ,the right lung4 #ae1 ,the axillary extension of the air-sac4 #af1 ,the obturator foramen4 #ag4 ,the pelvis4 ,these sacs do not communicate with each other and normally they are not fully inflated4 ,in some locations they extend into the bones and are in communication with the extensions of the bronchial tubes4 ,in fact1 by some anatomists they have been called 8bladder-like1 extra-pulmonary expansions of the bronchial tubes1 free from cartilage40 ,the air-sacs make the bird's body lighter1 thus making long-continued flight possible4 ,they are best developed in those birds which fly most4 ,there are four pairs of cells and one single cell from which all other expansions and extensions are made4 ,these sacs are as follows3 a single anterior thoracic1 and1 in pairs1 cervical1 anterior diaphragmatic1 posterior diaphragmatic1 and abdominal4 ,the ,anterior ,thoracic ,air-sac4--,the anterior thoracic air-sac is located above the clavicles and the interclavicular space1 in the cavity of the thorax4 ,it is related superiorly with the trachea and the esophagus2 laterally with the lungs and the cervical air-sacs2 inferiorly with the sternum1 the clavicle1 and the interclavicular aponeurosis2 posteriorly with the heart and the anterior diaphragmatic reservoir2 and anteriorly with the integuments of the neck4 ,it contains the inferior larynx and the two primary bronchi1 and large vascular trunks from which are given off vessels supplying the neck and the wings4 ,three prolongations1 called subpectoral1 subscapular1 and middle1 or humeral1 arise from the lateral walls of this air-sac4 ,these prolongations cross the walls of the thorax and pass around the articulation of the shoulder4 ,the subpectoral prolongation extends from the thoracic reservoir by an orifice situated behind the coracoid1 and passes beneath the tendon of the great pectoral muscle4 ,when the pectoralis major contracts1 this contraction dilates the subjacent cell and draws into it a greater quantity of air4 ,the subscapular and the humeral prolongations communicate with the thoracic air cell by a common opening situated behind the small adductor muscle of the humerus4 ,the subscapular prolongation1 after leaving this point1 spreads under the scapular and the subscapular muscle1 which it separates from the ribs and corresponding intercostal muscles1 and extends in a longitudinal direction4 ,the humeral prolongation1 smaller than the subscapular1 occupies the axilla1 and is in shape triangular4 ,it has from its summit into an infundibular fossa1 an extension which enters the canal of the humerus4 ,the walls of this cell form the lining of the air space in the humerus4 ,the thoracic air-sac thus possesses numerous membranous folds which divide its cavity4 ,the contiguous structures which it overlies1 as the trachea1 the esophagus1 the muscles of the inferior larynx1 as well as the arteries and veins1 make its outer walls irregular4 ,this orifice is dilated during inspiration1 by the contraction of the two first fasciculi of the diaphragm4 ,the ,cervical ,air-sacs4--,the two cervical air-sacs are located just above the thoracic air-sac at the inferior part of the neck and in front of the lungs4 ,they are cone-shaped with the base directed forward and the apex backward4 ,they are related superiorly with the cervical muscles1 and inferiorly with the thoracic air-sac from which they are separated by the trachea1 the esophagus1 the pneumogastric nerve1 and the jugular veins4 ,the walls touch each other internally1 and form a median septum which includes in its substance the two common carotid arteries4 ,externally they are related to the origin of the cervical nerves1 to each of which they contribute a small sheath4 ,they surround the vertebral artery1 and are connected with the subcutaneous muscles and the skin4 ,the summits communicate with the anterior diaphragmatic bronchus4 ,prolongations extend from their bases which conduct the air into all the vertebr of the neck and the back1 into all the vertebral ribs1 and into the spinal canal4 ,parallel with and adjacent to the vertebral arteries1 and lodged in the canals excavated in the transverse processes of the cervical vertebr1 are two cervical prolongations1 one on each side1 which extend to the cranium from the base of the cervical reservoirs4 ,from their sides1 at the last six cervical vertebr1 are six extensions in the form of diverticuli1 which1 lying against each other1 pass from each side into the muscles of the neck4 ,they are surrounded by a thin fibrous envelope1 a continuation of the mucous lining of the sac1 and apparently form a canal in the inferior part of this region4 ,these prolongations are better developed in palmipedes than in chickens4 ,on the internal side of these prolongations1 one or more foramina penetrate the vertebral segment1 which allow the extensions of the prolongations into the spinal canal4 ,chauveau states that 8as the medullary tissue is replaced by air in the bones of birds1 so is the subarachnoid fluid replaced by air around the spinal cord40 ,the prolongations extending from the cervical air-sacs1 having entered the thorax1 terminate by passing into the first dorsal vertebra4 ,after permeating every part of this vertebra1 it escapes by a lateral opening and forms a small sac located between the first two ribs1 near the origin of the first dorsal nerve4 ,from this sac an extension is given off1 which enters the second vertebral segment at the antero-lateral part2 from this point it passes back1 forming a new air-sac between the second and third ribs4 ,it now passes in the same manner into the third vertebra and extends through the third intercostal sac1 and so on till the last dorsal vertebra has been served4 ,at the same time that these sacs receive the air from the vertebr preceding them1 and transmit it to those which follow1 they communicate it to all the vertebral ribs4 ,the aerial currents which leave the cervical air-sacs do not communicate with those of the cranium4 ,experiments show that the cranial bones have apparently no communication with the respiratory apparatus4 ,the ,anterior ,diaphragmatic ,air-sac4--,the two anterior diaphragmatic or supero-posterior air-sacs are related with the lungs anteriorly1 and with the abdominal viscera posteriorly4 ,anteriorly also is the thoracic air-sac1 posteriorly are the posterior diaphragmatic air-sacs1 and laterally the ribs and the intercostal muscles and internally is the esophagus4 ,the lungs communicate with these air-sacs through circular openings from the great posterior diaphragmatic bronchus and frequently by a second opening from this same tube4 ,these are the only sacs which receive air from the lungs through two openings4 ,the ,posterior ,diaphragmatic ,air-sac4--,the two posterior diaphragmatic1 or infero-posterior air-sacs are oval in shape and located between the thoracic and the abdominal cavity4 ,they are related anteriorly with the anterior diaphragmatic air-sacs4 ,these two sacs form a vertical transverse partition4 ,the posterior diaphragmatic air-sacs are related posteriorly with the abdominal air-sacs from which they are separated by the diaphragm4 ,they are related below with the lateral parts of the sternum and the sternal ribs1 and externally with the ribs and the intercostal muscles4 ,these air-sacs communicate with the lungs through openings located in the middle part of the external border of the lung1 into the extremity of voluminous bronchial tubes which follow the direction of the largest air tubes4 ,the ,abdominal ,air-sacs4--,the two abdominal air-sacs located on each side of the abdominal cavity1 when inflated with air1 form enormous bladder-like structures4 ,they are related laterally with the abdominal wall and internally with the abdominal viscera4 ,the anterior extremities are in communication with the mesobronchi and are somewhat inflected to pass under the fibrous arches extending from the spine to the pelvis4 ,anteriorly these sacs adjoin the diaphragm1 the testes in the male1 and ovary in the female1 and to the parietes of the abdomen and those of the pelvis4 ,below and in front1 they rest on a fibrous septum1 which in all birds divides the abdominal cavity into two smaller cavities3 one anterior1 representing the abdomen and containing the liver2 the other posterior1 representing the pelvis and containing the gizzard and the intestines4 ,the anterior portion overlies the posterior part of the lobes of the liver1 the proventriculus1 the spleen1 and the gizzard4 ,the kidneys are located above these air-sacs4 ,dorsal to the sacs is also a part of the intestines and in the female the oviduct4 ,the abdominal air-sacs are attached by a ligament-like structure in their medial1 their anterior1 and their lateral margin4 ,the posterior1 the dorsal1 and the ventral margin are free4 ,mesially this attachment is to the mesentery1 connecting the left ccum to the dorsal margin of the gizzard1 and also to the mesentery of the proventriculus4 ,the anterior attachment is to the body wall and extends in front of the end of the ovary and the adrenal glands4 ,at the antero-lateral part of the body cavity the attachment extends in a widening band along the lateral side of the ovary and of the oviduct1 as far back as the caudal margin of the sac4 ,the lateral attachment is related to the kidney1 the dorsal ligament of the oviduct1 and the abdominal wall4 ,each of these abdominal sacs has three extensions3 one suprarenal and two femoral4 ,the suprarenal extension leaves the principal sac at the postero-external part of the kidney1 extends upward1 and forward1 and expands over the surface of the kidney4 ,at the internal border of the kidney1 this prolongation extends between the transverse processes of the sacral vertebr1 reaches a height of the first dorsal vertebra1 forms a triangular canal located above the sacrum in the sacral channel1 and is separated from its fellow by a series of corresponding spinous processes4 ,the two femoral extensions1 an anterior1 small1 and a posterior1 large1 extend from the abdominal air-sac at the cotyloid cavity1 leave the pelvis through the bony passage occupied by the crural vessels1 extend around the coxo-femoral articulation1 and terminate in a blind extremity4 ,in some birds1 particularly in birds of prey and ostriches1 there are prolongations extending into the femur1 entering through a foramen at the anterior part of the great trochanter4 ,summary of ,bones ,supplied by ,each ,air-sac4--,the thoracic air-sac communicates on each side of the thorax with twelve bones1 including the four sternal ribs4 ,it supplies air to the clavicles1 which are perforated at both their extremities1 and to the coracoids1 which are perforated just below their scapular extremity4 ,the sternum is supplied through two series of openings1 the middle ones that conduct air into the sternal ridge and the lateral ones1 eight in number and very small1 correspond to the intercostal spaces4 ,the sternal ribs are penetrated by small foramina at their inferior extremities4 ,from the subscapular extension the scapul receive air through one or two foramina at their anterior extremity4 ,the humeral prolongation supplies the humerus through a foramen located at the upper edge of the humeral fossa1 at the infero-internal part of the articular head4 ,the cervical air-sac furnishes air to all the cervical vertebr1 to all the dorsal vertebr1 and to all the vertebral ribs4 ,the anterior parts of the vertebr of the neck are supplied with air through the passage accommodating the vertebral artery4 ,the posterior parts of the vertebr are supplied by extensions from the interspinal canal4 ,the first extensions obtain entrance to the anterior segments by one or more openings of the inner wall of the intertransverse canals2 the median extensions penetrate the posterior segments by two openings1 a right and a left1 situated on the inner wall of those segments4 ,the first dorsal vertebra is supplied with air in the same manner1 by the middle and the lateral canals of the neck4 ,this air1 after passing through the first vertebra1 leaves by a lateral exit to enter a small air-sac4 ,from this it passes into the superior part of the second vertebra1 escapes from this through its lower portion1 to be received into a lateral sac1 and so on to the last dorsal vertebra4 ,these sacs also supply the vertebral ribs with air1 which enters them by very small openings located on their spinal extremities4 ,the diaphragmatic air-sacs do not have communications with the bones4 ,the abdominal air-sacs communicate with the sacrum1 the coccygeal vertebr1 the iliac bones1 and the femurs4 ,the air passing through the sacrum1 the coccyx1 and the ilium comes directly from the suprarenal extensions2 the air which fills the femoral cavity comes from the femoral extensions4 ,in some birds these air spaces are more greatly developed than in others4 ,the bones that are always aerated in all birds are the cervical and the dorsal vertebr1 the sternum1 and the humeri4 ,those aerated in some kinds only are the furculum1 the scapul1 the vertebral and the sternal ribs1 the sacrum1 the coccyx1 and the femurs4 ,those that are never aerated are the bones of the forearm1 the hand1 the leg1 and the foot4 ,the service of air to the bones in most parts of the body by the air-sacs1 as just shown1 is in special cases otherwise rendered4 ,the ,eustachian tubes furnish air to the bones of the cranium and to the upper jaw2 while the lower jaw receives air from the pneumatic foramen situated upon each ramus behind the tympanic articulation1 and from an air cell which surrounds the joint4 ,the cavities of the embryonic bones1 which afterward become pneumatic1 are filled with marrow4 ,selenka states that the invasion of the bones by the air is a late development1 and that in the humerus this invasion occurs after the twenty-second day in the life of the chick4 ,hunter and ,compar1 who have made extensive researches1 consider the function of the air-sacs as threefold4 ,first1 the air-sacs are subsidiary respiratory organs1 which aid in ridding the blood of waste products and in taking in oxygen4 ,second1 they aid mechanically the actions of respiration in birds4 ,during the act of inspiration the sternum is depressed1 the angle between the vertebral and the sternal ribs is made less acute1 and the thoracic cavity proportionately enlarged2 the air then rushes into the lungs and into the thoracic receptacles1 while those of the abdomen become flaccid4 ,when the sternum is raised1 or approximated toward the spine1 part of the air is expelled from the lungs and the thoracic air-sac through the trachea1 and part is driven into the abdominal receptacles1 which are thus alternately enlarged and diminished with the expansion and the contraction of the thorax4 ,hence the lungs1 notwithstanding their fixed condition1 are subject to due compression through the medium of the contiguous air receptacles1 and are affected equally and regularly by every motion of the sternum and of the ribs4 ,third1 they reduce decidedly the specific gravity of the whole body4 ,this must necessarily follow from the large spaces filled with air as well as from the absence in the bones of marrow and other fluids4 ,the air-sacs by their position also render equilibrium more stable4 ,,angiology ,the ,circulatory ,apparatus4--,the circulatory apparatus consists of two tubular systems3 the blood vascular system and the lymphatic system4 ,the blood vascular system consists of the heart1 the arteries1 the veins1 and the capillaries4 ,the heart is the central1 propelling organ4 ,the arteries form a series of efferent tubules1 which1 by branching1 constantly increase in number and decrease in caliber1 and which serve to carry the blood from the heart to the tissues4 ,the capillaries are extensions from these latter tubules into which the arteries empty1 and through the walls of which the interchange of elements between the blood and the other tissues takes place4 ,the veins form a system of converging tubules which receive the blood from the capillaries1 decrease in number and increase in size as they approach the heart1 and return the blood to that organ4 ,the lymphatic system consists of capillaries and veins alone4 ,as in the blood system1 the lymph capillaries collect the effete material and pour it into the lymph veins1 and these in turn1 carry it to the large blood veins adjacent to the heart4 ,both these systems have one and the same continuous lining1 which consists of a single layer of endothelial cells4 ,in the heart this lining is called the endocardium1 and in the vessels1 the endothelium4 ,it forms a perfectly smooth surface4 ,,the ,,heart 7,fig4 #ba1 ,no4 #g7 ,the heart of the domestic fowl is located in the median line of the thoracic cavity4 ,it is more anterior and mesial than in mammals4 ,its axis is parallel with the axis of the trunk4 ,the lungs being confined to the dorsal part of the trunk1 the lower part of the heart is not surrounded by them1 but extends backward1 the apex resting in the anterior part of the anterior median fissure of the liver4 ,the heart has the form of an acute cone 7,fig4 #ej1 ,no4 #a71 the apex of which is bluntly rounded4 ,the heart is surrounded by a sero-fibrous sac1 the pericardium4 ,this sac adheres to the cervical air reservoirs anteriorly and to the diaphragmatic septum posteriorly4 ,it is composed of two membranous layers3 the parietal1 external1 dense1 and fibrous2 and the visceral1 internal1 and serous4 ,the pericardial sac has no direct attachment to the heart1 except at the upper extremity where it surrounds the large vessels emerging from it4 ,the serous layer is reflected over the outer portion of the heart1 where it is called the epicardium4 ,the function of the pericardium is to prevent friction during the beating of the heart4 ,it contains a small amount of serous fluid for perfect lubrication4 ,this fluid is called the liquor pericardii4 ,internally the heart has four cavities3 two auricles and two ventricles4 ,the right ventricle is more crescent-shaped than in solipedes1 and in a manner envelops the left ventricle in front and to the right1 though it does not reach the point of the heart4 ,the right auricle is larger than the left4 ,the auriculo-ventricular valve is not tricuspid as in mammals4 ,this valve instead of being formed as usual by a membranous curtain1 with margins retained by cords fixed to the walls of the ventricles1 is composed of a wide muscular leaf1 which appears to be a portion of the inner wall of the ventricle detached from the interventricular septum4 ,this septum is convex2 and the auriculo-ventricular orifice is an oblique slit situated between it and the muscular valve in question2 so that1 when the heart wall contracts at the systole1 the valve is applied against this septum and closes the passage4 ,the bicuspid1 or auriculo-ventricular valve of the left side usually has two segments1 though occasionally there may be three4 ,the fossa ovalis is a depression behind the posterior semi-lunar valve in the septum of the heart4 ,the membranous septum closing the foramen ovale is complete and strong but thin and transparent4 ,the right auricle receives the blood from the two ven cav coming from the anterior extremity1 and from the posterior vena cava4 ,these empty into a sinus4 ,the left auricle has two vessels1 the pulmonary veins which bring blood to it from the lungs4 ,structure of the ,heart4--,the heart is lined by a serous membrane1 the endocardium1 which is a continuation of the endothelium of the blood-vessels4 ,there are a few muscular pillars in the inner wall1 called the column carn4 ,to give the heart its pumping power1 it is made up of contractile tissue1 a specialized kind of muscle called heart muscle4 ,it is involuntary-striated and occupies an intermediate position1 both morphologically and embryologically1 between smooth involuntary muscle and striated voluntary muscle 7,fig4 #gd1 ,no4 #d74 ,it1 like striated voluntary muscle1 is both transversely and longitudinally striated4 ,heart muscle cells are short1 thick cylinders1 which are joined end to end to form long fibers4 ,by means of lateral branches the cells of one fiber anastomoses with cells of adjacent fibers4 ,each cell of heart muscle contains one centrally located nucleus4 ,there is no distinct sarcolemma1 but the sarcoplasm is more dense near the surface of the cell1 which gives it the appearance of an enveloping cell wall4 ,there is a zone free from fibrill around the nucleus4 ,the longitudinal fibrill1 which make up the cell1 are held together by a cement-like substance4 ,the main mass of the heart wall1 called myocardium1 consists of the specialized muscular tissue just described4 ,the myocardium differs in thickness in different parts of the heart wall4 ,it is thickest in the left ventricle and thinnest in the auricles4 ,the left ventricle forces the blood through the systemic circulation and hence must be thicker to give it more power than is needed for the right ventricle1 which forces the blood only through the lungs4 ,the auricles are thinnest of all2 for they receive the blood and pass it only to the chambers below4 ,the auricular appendages at the base of the heart in fowls are not so well marked as in mammals4 ,the auricular muscles consist of an outer coat common to both auricles1 the fibers of which are transverse and of an inner coat1 independent for each auricle1 the fibers of which are longitudinal4 ,between the two coats1 occur bundles of muscle the fibers of which run in various directions4 ,the disposition of the muscle tissue of the ventricles is much more complicated4 ,it is composed of several layers of fibers intricately interwoven4 ,the endocardium1 covering the inner surface of the myocardium1 forms a serous lining of all the chambers of the heart4 ,at the arterial and venous openings it is continuous with and similar in structure to the intima of the vessels4 ,the endocardium consists of two layers1 an external layer closely attached to the myocardium and consisting of mixed fibers1 including those of elastic tissue and smooth muscle cells2 and an inner1 single layer of endothelial cells1 spoken of above4 ,the heart is supplied with nutrient blood by the two coronary arteries1 which are given off from the common aorta just above the semi-lunar valves4 ,a right1 or anterior1 and a left1 or posterior1 coronary from their point of origin1 turn in a ventral direction between the root of the aorta and the pulmonary artery1 the right going to the right coronary groove and the left to the left coronary groove in the crown furrow4 ,from here they send branches into the heart4 ,the anterior1 right1 coronary1 or coronaria dextra1 the larger1 is given off from the inferior wall of the aorta4 ,it divides into a ramus superficialis and a ramus profundus4 ,the ramus superficialis enters the crown furrow and divides into two or three branches on the right heart wall4 ,these branches extend to the apex of the heart4 ,twigs from this artery along its course extend into the muscular wall reaching the posterior of the coronary groove where they anastomose with those of the left coronary1 the ramus profundus1 and with other branches from the same artery4 ,the ramus profundus1 larger than the preceding1 gives off fine branches into the walls of the aorta and of the pulmonary artery1 then enters from behind into the right wall of the septum ventriculorum1 extends into the apex of the heart1 and supplies the septum1 or right inner chamber wall with the last branch1 this breaking through the posterior wall of the auricular appendage4 ,the posterior1 left coronary1 or coronaria sinistra1 originates from the dorsal wall of the aorta1 proceeds as one branch on the upper surface of the left auricular appendix1 and then extends between the left appendix and the pulmonary artery to the ventral surface of the heart4 ,on the left side it supplies the wall of the pulmonary artery and gives off a ramus profundus4 ,it sometimes divides into two parts and supplies the ventral wall of the right chamber and then extends to the left wall of the septum medium4 ,the rest of the coronaria sinistra enters into the left crown furrow as the ramus superficialis1 which provides the left and dorsal upper surface of the left chamber to the apex4 ,from this furrow it extends into the left chamber and the left appendage1 and finally fuses with the ramus superficialis of the coronaria dextra4 ,,the ,,blood-,,vessels ,the blood-vessels consist of arteries1 veins and capillaries4 ,the ,structure of the ,capillaries and ,arteries4--,the capillaries are minute vessels which connect the arterioles1 or terminal arteries1 with the venules1 or terminal veins4 ,they are only from #f to #ad microns in diameter4 ,their walls consist of a single layer of endothelial cells1 which are somewhat elongated in the long axis of the vessels4 ,their edges are serrated1 and are united by a small amount of intercellular cement-like substance4 ,capillaries branch without diminution in caliber1 and these branches anastomose to form capillary networks1 the meshes of which differ in size and shape in different tissues and organs4 ,the largest meshed networks occur in the serous membranes and in the muscles2 and the smallest occur in the glands1 such as the liver4 ,the walls of the arteries are thick and stand open when empty1 owing to the elastic tissue contained in their walls1 while the walls of the veins collapse when empty1 owing to their containing a smaller amount of elastic tissue4 ,the arterial wall is provided with three coats3 tunica intima1 or inner coat2 tunica media1 or median coat2 and tunica adventitia1 or outer coat4 ,the tunica intima consists of a single layer of endothelial cells1 continuous with and similar to that forming the walls of the capillaries4 ,in passing from the capillaries to the arterioles1 there is first a thin coat1 or sheath-like layer1 of connective tissue around the outside of the endothelial tubes4 ,further along1 isolated smooth muscle cells arranged in a circular manner occur between the endothelial layer and the layer of connective tissue1 this structure forming vessels called precapillary arteries4 ,further along still1 the muscle cells form a complete layer2 in this section the vessels are called arterioles and are made up of three coats3 the inner endothelial1 the middle muscular1 and the outer fibrous4 ,in arteries of medium size the intima consists of the endothelial layer1 a layer of delicate white and elastic fibers1 connective-tissue cells1 and the membrana elastica interna1 or an outer layer1 the elastic layer1 of the intima4 ,the media consists of a thick coat of circularly arranged smooth muscle cells1 its thickness depending largely upon the size of the vessels4 ,there is also a small amount of fibrillary connective tissue1 which supports the muscle cells4 ,elastic tissue is present in the media1 the amount depending on the size of the vessel1 the larger the vessel the more elastic tissue there is present4 ,in the large arteries coarse elastic fibers intermingle with the finer ones4 ,when much elastic tissue is present the muscle cells are separated into more or less well-defined groups4 ,the adventitia is composed of loose connective tissue with some elastic fibers4 ,a few smooth muscle cells are present1 which1 as are also the elastic fibers1 are arranged longitudinally4 ,the adventitia1 blending with the connective tissue surrounding the arteries1 serves to anchor the vessels to the surrounding structure4 ,structure of the ,veins4--,in many respects the walls of the veins resemble those of the arteries4 ,the same three coats exist and the same elements enter into their structure4 ,the transition from capillary to small veins1 and from those to larger veins1 is similar to the transition from the arteries to capillaries1 in inverse order4 ,the walls are not so thick as those of arteries4 ,the elastic tissue is much less in quantity and in smaller veins disappears4 ,there is not a clear line of demarcation between the intima and the media4 ,the veins of birds differ from those of mammals in that they have fewer valves4 ,the valves are also less perfect1 and often permit a backward flow of blood4 ,the walls of the arteries and of the veins are supplied with nutrient blood-vessels4 ,these are called the vasa vasorum1 or blood-vessels of the blood-vessel wall4 ,they are mostly in the adventitia4 ,they may arise from the vessel to which they are distributed or take origin from an adjacent vessel4 ,these small arteries supplying the vessel coat after terminating into capillaries form small veins through which the blood1 from the structure of the vessel wall1 is returned4 ,the walls of the blood-vessels are supplied with both medullated and non-medullated nerves4 ,the non-medullated nerve fibers are axones of the sympathetic neurones and control the caliber of the vessels4 ,these fibers are called the vasomotor nerves4 ,they form plexuses in the adventitia1 from which are given off branches which penetrate the media and terminate on the muscle cells4 ,the medullated nerves are the axones of the spinal nerves4 ,the larger fibers are found in the connective tissue outside the adventitia and give off branches to the media where they divide repeatedly1 lose their sheath1 and terminate in the media and at times in the intima4 ,,the ,,arterial ,,trunks ,the common aorta is short2 it originates from the left ventricle 7,fig4 #fa;,b1 ,no4 ,k1 #ad71 and is guarded by three semi-lunar valves4 ,the aorta breaks through the pericardium just to the right of the pulmonary arteries in a ventral direction2 it then turns upward dorsally and to the right of the inferior bodies of the vertebr4 ,it is then directed anteriorly1 and dorsally to the right bronchus1 between the right bronchus and the right lung4 ,the right and the left coronaries are given off from the common aorta2 they have been discussed4 ,there is next given off the left brachio-cephalic or brachio-cephalic sinister artery 7,fig4 #fa;,b1 ,no4 ,k1 #aj71 which is just above the border of the base of the heart4 ,this artery passes upward and slightly forward1 over the center of the inferior larynx4 ,just beyond this point the subclavian artery is given off2 this artery later becomes the axillary and the axillary the brachial artery4 ,then there is given off the anterior and the posterior thoracic arteries2 and finally1 the pectoral1 which supply the pectoralis muscles and later terminate in the carotid1 the vertebral1 and the cervical arteries4 ,the carotid artery gives off an esophageal artery4 ,the other arterial trunk given off from the common aorta is the right brachio-cephalic or brachio-cephalic dexter 7,fig4 #fa;,b1 ,no4 ,k1 #ah74 ,the right brachio-cephalic artery gives off the subclavian1 which continues as the axillary1 and continues as the brachial artery4 ,there is given off the anterior and the posterior thoracic1 the right carotid 7,fig4 #fa;,b1 ,no4 ,k1 #aa71 the vertebral1 and the dorsal4 ,the last continues as the cervical4 ,illustration3 ,,fig4 #fa;,b4 ,k4 ,the arterial trunks4 #a1 ,the middle sacral artery4 #b1 ,the hypogastric artery4 #c1 ,the posterior mesenteric artery4 #d1 ,the ischiadic artery4 #e1 ,the femoral artery4 #f1 ,the renal artery4 #g1 ,the left pectoral artery or thoracico caudalis4 #h1 ,the left axillary artery4 #i1 ,the left carotid artery4 #aj1 ,the left brachio-cephalic artery4 #aa1 ,the right carotid artery4 #ab1 ,the right brachial artery4 #ac1 ,the right pectoral artery4 #ad1 ,the common carotid artery4 #ae1 ,the posterior aorta4 #af1 ,the celiac axis4 #ag1 ,the anterior mesenteric artery4 #ah1 ,the right brachio-cephalic artery4 #ai1 ,the auricular portion of the heart4 #bj1 ,the ventricular portion of same4 #ba1 ,sterno-clavicular artery4 #bb1 ,anterior thoracic4 ,l4 ,the venous trunks4 #a1 ,the caudal vein4 #b1 ,the coccygeo-mesenteric vein4 #c1 ,the posterior mesenteric vein4 #d1 ,the anterior mesenteric vein4 #e1 ,the gastro-duodenal vein4 #f1 ,the portal vein4 #g1 ,the hepatic vein4 #h1 ,the left anterior vena cava4 #i1 ,the left pectoral vein4 #aj1 ,the left brachial vein4 #aa1 ,the left jugular vein4 #ab1 ,the right jugular vein4 #ac1 ,the right brachial vein4 #ad1 ,the right pectoral vein4 #ae1 ,the right anterior vena cava4 #af1 ,the posterior vena cava4 #ag1 ,the common iliac vein4 #ah1 ,the femoral vein4 #ai1 ,the renal vein4 #bj1 ,the internal iliac vein4 #ba1 ,the hypogastric vein4 #bb1 ,the auricular portion of the heart4 #bc1 ,the ventricular portion of same4 ,the pulmonary arterial trunk is given off from the conus arteriosus of the right ventricle4 ,it is guarded at its origin by three semi-lunar valves similar to those of the aorta4 ,the trunk divides into two pulmonary arteries1 which are short1 one called the pulmonalis dexter and the other the pulmonalis sinister4 ,the former goes to the right and the latter to the left lung4 ,each branch penetrates the lung near the bronchus4 ,these arteries divide1 or branch1 similarly to the bronchi4 ,following the branchings of the bronchi1 they finally terminate into the lung capillaries1 forming networks on the bronchi and the air-tube terminals4 ,,branches ,,of ,,the ,,brachio-,,cephalic ,,artery 7 ,thyroidea 7 7 ,cervicalis inferior 7 ,vertebralis 7 ,vertebralis anterior 7 7 ,vertebralis posterior 7 7 ,arteria cervicalis ascendens 7 ,bronchiales 7 ,truncus 7 ,inferior esophageal 7 caroticus 7 ,subcutaneous colli 7 7 7 ,carotis cerebralis 7 7 ,carotis 7 ,cervicalis superior 7 7 communis 7 ,occipitalis 7 7 7 ,carotis externa 7 7 ,spinalis anterior 7 ,basilaris 7 ,cerebelli inferior ,brachio-cephalic 7 7 7 ,clavicularis 7 7 ,sterno-clavicularis 7 ,sternalis 7 7 7 ,acromialis 7 7 7 7 7 ,subscapularis 7 7 7 7 ,ulnaris 7 ,subclavia 7 ,axillaris 7 ,brachialis 7 ,brachialis profunda 7 7 7 ,radialis 7 7 ,humeralis 7 ,circumflex humeralis 7 7 7 anterior 7 7 7 ,thoracica externa 7 ,thoracalis 7 7 ,arteria thoracica 7 ,thoracica inferior 7 longa 7 7 ,mammaria interna 7 ,circumflex humeralis posterior ,brachialis profunda 7 ,collateral ulnaris 7 ,collateral radialis ,the cord-like remnant of the ductus botalli1 or embryonal connection between the lung arterial trunk and the anterior aorta1 has been observed but is rare in grown birds4 ,the arteries1 the veins1 and the lymphatic vessels of birds anastomose far more frequently than those of mammals4 ,,branches ,,of ,,the ,,arteria ,,carotis ,,cerebralis ,,interna 7 ,occipitalis 7 ,occipitalis sublimis 7 7 ,occipitalis profunda 7 ,meningea 7 7 ,temporalis 7 7 7 ,rete temporale 7 ,ophthalmica 7 ,recurrent ophthalmicum 7 ,rete ethmoidalis 7 externa 7 ,ethmoidalis 7 7 ,plexus palpebralis 7 7 ,plexus alveolaris inferior 7 7 ,plexus muscularis ,carotis cerebralis 7 ,plexus temporalis 7 ,plexus lacrimalis 7 7 ,ramus ciliaris posticus 7 7 ,meningea media 7 7 7 ,sphenoidea 7 ,ethmodalis 7 7 ,spheno-maxillaris 7 ,ethmoidalis 7 externa 7 7 7 ,ophthalmica 7 7 ,ethmoidalis 7 7 7 interna 7 7 interna 7 ,cerebralis 7 7 7 ,ramus 7 ,sylvi 7 anterior 7 ,cerebralis profunda 7 ,choroid plexus 7 ,arteria centralis retin 7 ,ramus posterior ,,branches ,,of ,,the ,,arteria ,,carotis ,,externa 7 ,hyoidea ,carotis externa 7 ,laryngea superior 7 ,facialis 7 ,lingualis ,,branches ,,of ,,the ,,arteria ,,carotis ,,facialis 7 ,auricularis ,facialis 7 ,facialis interna 7 ,alveolaris inferior 7 ,mentalis 7 ,maxillaris interna 7 ,facialis externa ,,branches ,,of ,,the ,,carotid ,,trunk ,the carotis communis artery springs from the carotid trunk of the brachio-cephalic4 ,it is directed horizontally1 ascending to the ventral side of the neck4 ,it then extends downward to the inferior median neck region4 ,just after leaving its origin it gives off several small branches to the bronchi and to the esophagus1 and extends toward the head4 ,the carotid lies on the thyroid gland and at this point touches the jugular vein 7,fig4 #ba74 ,at this point the thyroid arteries are given off from the carotid trunk4 ,the thyroid gland also receives blood from the bronchialis artery4 ,dorsalward and near the thyroid gland the carotid artery gives off a branch 7the bronchialis7 which accompanies the recurrent laryngeal nerve1 along the inferior larynx and the bronchi1 and supplies the lung substance and that part of the esophagus in this region4 ,the vertebral artery is given off from the carotid trunk1 dorsalward to the thyroid gland1 and on the left side4 ,the right vertebral artery may be given off from the brachialis dextra or right brachialis4 ,the inferior esophageal artery is given off from the ventral side of the carotid1 supplies the esophagus1 extends then to the skin of the neck and to the trachea1 is directed anteriorly toward the head and anastomoses with the vertebral artery4 ,this artery accompanies the vagus nerve and forms a collateral artery to the carotid and the vertebral artery4 ,the subcutaneous colli springs from the carotid artery near the thyroid gland and communicates with the inferior cervical artery1 which1 in turn springs from the vertebral artery4 ,the ,common ,carotid4--,near the last cervical vertebra the two carotid arteries occupy the same channel1 to which they are attached by fascia1 and1 lying close to the inferior surface of the bodies of the cervical vertebr1 are covered by the colli muscles4 ,near the third or the fourth cervical vertebra1 the two carotid arteries separate4 ,near the atlas each carotid divides into the carotis cerebralis and carotis externa4 ,near this division the superior cervical artery branches off4 ,this latter artery extends down the neck in company with the pneumogastric nerve and the jugular vein1 supplies the skin and the neck muscles1 and anastomoses with the inferior cervical artery and the subcutaneous colli artery4 ,the occipital artery originates either from the carotis communis or sometimes from the superior cervical4 ,,branches ,,of ,,the ,,carotis ,,cerebralis ,the branches of the carotis cerebralis are as follows3 #a4 ,the occipitalis 7,fig4 #gb1 ,no4 #ah71 which in turn gives off1 first1 the occipitalis sublimis4 ,the occipitalis sublimis supplies the outer and the middle portion of the digastricus and the posterior mylo-hyoideus muscle4 ,it also gives off1 second1 the occipitalis profunda which supplies the inner portion of the digastricus muscle and becomes the meningeal artery1 which passes through the foramen vagi1 entering the brain cavity1 where it supplies the coverings of the brain as far as the sella turcica4 ,superficial branches of this artery are distributed to the muscles in the region of the atlas and anastomose with the vertebral artery4 #b4 ,the ophthalmica externa1 which passes below the articulation of the quadrate bone1 around the tympanic cavity1 enters the canalis caroticus1 and passes into the cranial cavity4 ,the ramus occipitalis1 passing out of the same foramen1 again enters the diplo of the cranium2 then after passing dorsally over the upper outer semicircular canal of the ear1 passes backward through the occipital bone4 ,the ophthalmica externa 7,fig4 #gb1 ,no4 #i7 forms a main trunk and gives off two branches3 the temporal artery and the recurrent ophthalmic4 ,the recurrent ophthalmic gives off the rete temporalis1 rete ethmoidalis1 a branch to the orbital gland1 and finally anastomoses with its own branches and with those of the internal ophthalmic at the olfactory foramen and aids in forming the ethmoidal artery4 ,these arteries supply blood by giving off branches to the muscles of the eye1 sclerotic coat1 iris1 choroid coat1 and the ciliary bodies4 ,it gives off another branch to ,harder's gland1 and finally anastomoses with the ethmoidalis4 #c4 ,the plexus temporalis1 rete mirabile ophthalmicum1 or wonderful network 7,fig4 #gb1 ,no4 #h71 is formed between the second and the third trunk of the trigeminus nerve and the rete ophthalmicum4 ,inferior to this is the alveolar plexus1 which plexus accompanies the third branch of the trigeminus into the lower jaw4 ,two main branches form this plexus1 one coming from the carotis facialis1 which anastomoses with the alveolar artery4 ,the palpebral plexus lies between the trunks of the trigeminus1 and supplies mainly the lower eyelid4 ,the plexus muscularis extends to the fifth portion of the temporal muscle4 ,the plexus lacrimalis forms on the posterior orbital wall on the ramus ethmoidalis and supplies the lacrimal gland and the upper eyelid4 ,it anastomoses with branches from the facial artery4 ,the ramus ciliaris posticus supplies the inferior rectus and the external rectus muscle of the eyeball4 ,it anastomoses with the ophthalmica externa4 ,the median meningeal artery passes through the foramen occupied by the second branch of the trigeminal nerve4 ,passing into the cranial cavity1 it supplies the dura mater4 ,before passing into this foramen1 small branches are given off1 which supply the skin and the temporal muscle2 and some branches anastomose with the superior cervical and the ethmoidal arteries4 #d4 ,the ,cerebral ,artery4--,each cerebral artery enters the cranial cavity through the canalis caroticus located in the sphenoid bone1 passes forward medially from the cochlea1 dorsally from the ,eustachian tube1 and passes through a small canal which opens on the inner surface of the sella turcica4 ,originating in this foramen1 the sphenoid artery divides into two branches which anastomose with the pterygoidean and the pterygo-pharyngeal artery and which supply the upper jaw and the throat regions4 ,the spheno-maxillaris artery supplies the gums4 ,the right and the left cerebral arteries unite at the sella turcica4 ,after this union they divide again immediately and pass to the base of the brain1 where they give off twigs to the optic nerve1 to the optic chiasm1 and where also is given off the arteria retin centralis4 ,passing posteriorly each cerebral artery gives off the ramus posterior1 and then passes to the side of the cerebellum4 ,the basilar artery1 a continuation of the anterior spinal artery1 is located ventrally and mesially to the cerebellum4 ,laterally and inferiorly the basilar artery gives off the inferior cerebellar artery4 ,the ramus anterior is given off from the cerebralis artery and continues as the internal ophthalmic artery4 ,the ramus anterior also gives off the sylvian artery1 which supplies the sides of the cerebrum and the middle brain4 ,in the fissure between the hemispheres and the optic thalamus is located the arteria cerebri profunda4 ,this artery passes along the median surface of the cerebrum and in its course supplies the adjacent parts4 ,it enters into the formation of the choroid plexus of the lateral ventricle4 ,the internal ophthalmic artery extends out of the cranial cavity1 through the optic foramen1 into the orbital cavity4 ,it passes upward along the interorbital wall and supplies the optic nerve1 the trigeminus nerve trunk1 and the eye muscles1 and dorsally anastomoses near the olfactory nerve with the rete ethmoidale and the external ophthalmic artery1 and continues as the ethmoidal artery4 ,the ethmoidal artery supplies the supra-orbital gland and the gland of ,harder4 ,it gives off twigs to the rete ophthalmicum and other branches to the skin of the frontal region1 where it anastomoses with branches of the external facial artery4 ,these branches in the frontal region are rather large4 ,large branches are given off to the comb4 ,the arteria ethmoidalis externa originates in the nasal cavity from a division of the ethmoidal artery4 ,the external ethmoidal artery passes below the lacrimal bone1 extends forward1 supplies the walls of the nasal cavity1 and finally sends a branch anteriorly into the upper median portion of the jaw bone1 and other branches to the septum nasi and other parts of the nasal cavity4 ,there are frequent anastomoses between the ethmoidalis interna1 the facialis1 and the spheno-maxillary artery4 ,the internal ethmoidal artery supplies principally the posterior turbinated bones and septum nasi4 ,,branches ,,of ,,the ,,external ,,carotid ,,artery ,branches from the external carotid and the facial artery supply the tongue and its muscles1 the larynx1 the lower jaw bone1 the gums1 and the upper lateral facial region4 ,the external carotid 7,fig4 #fb1 ,no4 ,a1 #h7 gives off the following branches3 ,first1 the hyoid artery 7,fig4 #gb1 ,no4 #ab7 which supplies the inner portion of the depressor mandibular and also the cornua of the os hyoideum1 and extends to the tip of the tongue4 ,second1 the superior laryngeal artery 7,fig4 #gb1 ,no4 #af7 which supplies the sterno-brachialis and gives off branches which extend downward to the trachea and to the esophagus4 ,the main artery passes along the left side of the esophagus and anastomoses with branches of the inferior esophageal1 forming collateral circulation in that region4 ,illustration3 ,,fig4 #fb4 ,a4 ,blood-vessels of the head4 #a1 ,the cerebellum4 #b4 ,the cerebrum4 #c1 ,the semicircular canals4 #d1 ,sinus occipitalis superior4 #e1 ,sinus temporalis sphenoideus4 #f1 ,sinus transversus dexter4 #g1 ,superior esophageal artery4 #h1 ,carotis externus4 #i1 ,lingual artery4 #aj1 ,sinus longitudinalis4 ,b4 ,veins of the antero-inferior part of the head and neck4 #a1 ,the right carotid artery4 #b1 ,the left carotid artery4 #c1 ,vena jugularis dexter4 #d1 ,vena vertebralis dexter4 #e1 ,transverse vein4 #f1 ,vena cephalica dexter anterior4 #g1 ,vena lingualis4 #h1 ,vena cephalica posterior4 #i1 ,vena facialis externa dexter4 #aj1 ,vena infrapalatina4 #aa1 ,posterior nares4 #ab1 ,vena facialis interna4 #ac1 ,vena facialis externa sinister4 ,c4 ,the brain4 #a1 ,medulla oblongata4 #b1 ,cerebellum4 #c1 ,optic lobe4 #d1 ,cerebrum4 #e1 ,longitudinal fissure4 #f1 ,transverse fissure4 #g1 ,olfactory nerve4 #h1 ,optic nerve4 #i1 ,optic commissure4 #aj1 ,motor oculi4 #aa1 ,patheticus4 #ab1 ,trigeminal1 or trifacialis4 #ac1 ,abducens4 #ad1 ,facialis4 #ae1 ,auditory1 or acousticus4 #af1 ,glosso-pharyngeus4 #ag1 ,pneumogastric4 #ah1 ,spinal accessory4 #ai1 ,hypoglossus4 #bj1 ,hypophysis4 #ba1 ,crus cerebri4 #bb1 ,ganglion on superior nerve trunk4 #bc1 ,spinal cord4 #bd1 ,a pair of spinal nerves4 ,third1 the lingualis artery 7,fig4 #fb1 ,no4 ,a1 #i7 which lies between the mylo-hyoideus and the posterior part of the hyoid bone4 ,it supplies the tongue muscles4 ,it passes to the median surface of the lower jaw bone1 where are given off small branches which enter the jaw and anastomose with the inferior alveolar artery4 ,fourth1 the ,facial ,artery4--,the facial artery divides into the following branches3 ,the auricular artery is given off near the articulation of the os quadratum with the os zygomaticum4 ,it is located at the outer auditory canal1 and its branches are distributed to the parotid region and to the depressor mandibular1 or digastricus1 muscle4 ,the external facial artery is located between the os quadratum and the masseter muscle4 ,it gives off a branch to the lower jaw bone and to the skin of that region1 and then passes to the lacrimal bone and supplies branches to the commissure of the mouth1 the auditory canal1 the masseter muscle1 the three eyelids 7upper and lower eyelids and the membrana nictitans71 the nose cavity1 and the skin in the frontal region4 ,it communicates on the other side with the ethmoidal artery4 ,the internal facial artery passes over and through the os pterygoideum1 supplies all the jaw muscles1 and is continued as the inferior alveolar artery4 ,the inferior alveolar artery enters the canal of the lower jaw bone along with the mandibular nerve4 ,it is finally continued as the mental artery1 leaving the canal1 and passing to the outer jaw surface4 ,the facialis continues as the internal maxillary artery4 ,the internal maxillary artery 7,fig4 #gb1 ,no4 #ae7 supplies the pterygoid muscle1 the upper part of the pharynx1 the commissure of the mouth1 the salivary gland region1 the gums1 and finally anastomoses with branches of the spheno-maxillaris artery4 ,,branches ,,of ,,the ,,vertebral ,,artery ,the vertebral artery is given off1 dorsally near the thyroid gland1 from the carotis communis or from the carotid trunk4 ,the vertebral artery passes horizontally and dorsally into the canals formed in the transverse processes of the cervical vertebr4 ,after it leaves the carotid1 it is divided into anterior and posterior branches4 ,the posterior vertebral artery passes in the canals of the transverse processes of the fifth or sixth dorsal vertebra4 ,it sends branches into the vertebr1 into the spinal canal1 and into the intercostal muscles between the ribs and anastomoses with the intercostal arteries4 ,the anterior vertebral artery is larger than the posterior4 ,it extends laterally along the side of the neck in the foramen of the transverse processes of the cervical vertebr1 and lies along the course of the inferior vertebral vein and the deep imbedded trunk of the sympathetic nerve4 ,it continues to the head4 ,in its passage it gives off to each vertebral segment a dorsal and a ventral branch4 ,twigs from these branches pass into the bodies of the vertebr and the spinal canal1 giving nutriment to the bony structure and to the spinal cord and its coverings4 ,other twigs are distributed to the muscles of the neck and some finally anastomose with branches of the carotis communis4 ,this artery1 reaching the head1 gives off a long anastomosing branch which passes between the atlas and posterior part of the occipital bone and joins the ramus profundus and the occipital artery1 thus again communicating with the carotid artery4 ,the remainder of the vertebral artery is small and passes through the foramen magnum into the cranial cavity where it anastomoses with terminal branches of the cerebral artery4 ,at the base of the neck and before the vertebral artery enters the canal of the cervical vertebr1 it gives off the arteria cervicalis ascendens1 superior artery of the crop 7,fig4 #gc1 ,no4 #ah7 which branches out on the upper surface of the crop is also distributed to the neck muscles1 and later subdivides into the transverse cervical arteries which supply the skin and the muscles of the base of the neck1 and the shoulder region4 ,on the ventral side of the neck there are given off two subvertebral carotid arterial branches4 ,they lie in a shallow furrow on the ventral side of the cervical vertebr and close to the median line4 ,,branches ,,of ,,the ,,subclavian ,,artery ,the subclavian artery 7,fig4 #bj1 ,no4 #ac2 ,fig4 #gc1 ,no4 #aa7 gives off the following branches3 #a4 ,sterno-clavicularis 7,fig4 #gc1 ,no4 #i7 which originates on the upper part of the subclavia1 between the carotid artery and external thoracic 7,fig4 #gc1 ,no4 #c71 divides into many branches4 ,the sterno-clavicularis gives off the sternal artery1 which enters by the side of the supra-coracoid muscle and the anterior rim of the sternum4 ,it is distributed to the inner surface and over the air-sac4 ,another outside branch passes the posterior end of the crista sterna and supplies the large breast muscles4 ,the clavicular artery 7,fig4 #gc1 ,no4 #h7 accompanies the clavicle to the shoulder-joint4 ,the acromial artery is given off from the sterno-clavicularis on the ligament near the shoulder-joint4 #b4 ,the thoracic artery branches from the subclavian artery 7,fig4 #gj1 ,no4 #d74 ,the thoracic artery gives off the following branches3 ,the internal mammary1 or internal thoracic artery 7,fig4 #gc1 ,no4 #af7 arises on the inner side of the sternum and extends downward and backward1 giving nutrient branches to the anterior vena cava and to the diaphragm4 ,at the point of the costo-sternal muscle it divides into an inner and an outer branch4 ,the inner branch supplies the costo-sternal muscle and extends along the ribs and along their juncture with the breast-bone4 ,it finally extends posteriorly1 giving numerous branches to the abdominal muscles4 ,the outer branch is distributed in a similar manner1 giving off branches to the diaphragm and to the abdominal muscles1 and anastomoses1 on the surface of the abdominal muscles1 with the epigastric artery4 ,the external thoracic artery 7,fig4 #gc1 ,no4 #c71 ramus superior1 supplies principally the large breast muscles4 ,the inferior thoracic artery1 external ramus inferior1 passes along the outside of the pectoralis major muscle1 extends downward1 and gives off the arteria thoracica longa 7subcutaneous thoracic74 ,this latter artery supplies the skin of the breast region4 ,other branches are given off to the muscles of the breast and to the skin of the region1 and some finally anastomose with the branches of the sternal artery4 #c4 ,the axillary artery 7,fig4 #gc1 ,no4 #ab7 extends out of the thoracic cavity along with the brachial nerve plexus4 ,it gives off the subscapularis which supplies the muscles of the scapular region4 ,the axillary artery terminates as the brachialis which passes between the biceps brachii and anconeus muscles downward along the humeral shaft4 ,it gives off the anterior humeral circumflex artery and the brachialis profunda artery 7,fig4 #fh1 ,no4 #c74 ,it gives off near the elbow-joint the ulnar and radial arteries4 ,the anterior circumflex humeral artery passes through the short head of the biceps and gives off a branch to the biceps muscle1 supplying the insertional part of the breast muscles4 ,,branches ,,of ,,the ,,brachialis ,,profunda ,the brachialis profunda artery 7,fig4 #fh1 ,no4 #c7 continues as the posterior circumflex humeral artery4 ,this artery supplies the muscles of the posterior part of the humerus1 the skin of the wing1 and the muscles of the brachial region4 ,the trunk of the arteria brachii profunda passes downward along the anconeus muscle1 supplying that muscle and giving off the collateral ulnar artery4 ,on the ulnar olecranon it anastomoses with the recurrent ulnar1 thus establishing1 at this region1 collateral circulation4 ,the rest of the brachialis sends branches to the biceps muscle and to the skin of the upper arm1 and finally gives off the arteria collateralis radialis1 which supplies the condylo-ulnaris4 ,it then anastomoses with the end branches of the recurrent radialis artery4 ,the radial artery 7,fig4 #fg1 ,no4 #d7 passes downward on the outer rim of the forearm4 ,it continues down to the carpal region1 where it supplies the muscles and the skin of the carpal region it gives off the recurrent radial1 which passes on the middle finger and finally anastomoses with the collateral radialis artery4 ,the ulnar artery 7,fig4 #fh1 ,no4 #f and #i7 passes downward on the inner surface of the ulna to the carpal region where it gives off a branch to the wing plexus and divides into two branches1 the smaller branch supplying the thumb 7,fig4 #fh1 ,no4 #g74 ,this branch passes down the radial side of the middle finger to the last joint of the second finger4 ,the larger 7,fig4 #fh1 ,no4 #h7 lies between the second and the third finger bones1 and passes through a slit between these two bones to the flexor side of the hand and extends to the last finger-joint1 supplying the structures in the region4 ,the ulnar artery gives off a small arterial twig to the papilla of each large wing feather 7,fig4 #fg1 ,no4 #f74 ,the recurrent ulnar passes backward to the olecranon of the ulna and supplies the muscles1 the skin1 the feathers1 and other structures of the region1 and terminates in end collateral ulnar branches 7,fig4 #fg1 ,no4 #e74 ,,branches ,,of ,,the ,,posterior ,,aorta#g 7 ,esophageal 7 ,intercostales 7 ,dorsal 7 ,lumbars 7 ,spermatics 7 ,renals 7 ,ovarian 7 ,celiac 7 ,recurrent esophageal 7 axis 7 ,recurrent intestinalis 7 ,recurrent ilio-colicus 7 7 ,posterior or recurrent sinister 7 ,renalis 7 7 ,anterior or recurrent dexter 7 ,splenics 7 7 7 ,hepatic 7 7 ,hepatica dextra 7 ,gastric 7 ,posterior 7 ,sacralis media 7 ,coccyge laterales aorta 7 7 ,coccygea media 7 ,coccyge laterales 7 7 ,anterior mesenteric 7 ,recurrent ilio-celiacus 7 7 ,recurrent superior hemorrhoidal 7 ,posterior mesenteric 7 ,median hemorrhoidal 7 7 ,recurrent renalis 7 7 ,tibialis postica 7 ,ischiadica 7 ,tibialis antica 7 ,peroneal 7 ,anterior tibial plexus 7 7 ,arteria ovarialis 7 ,pudenda communis 7 ,renalis 7 7 ,hemorrhoidalis intima 7 7 ,pudenda externa 7 7 ,crural 7 ,internal pelvic 7umbilical7 7 7,external iliac7 7 ,circumflex femoris 7 7 ,femoralis ,footnote #g3 ,nomenclature used by ,bronn4 ,the posterior aorta 7,fig4 #fc1 ,no4 #b7 passes backward along the inferior part of the bodies of the dorsal and lumbo-sacral vertebr4 ,in the thoracic cavity it lies dorsal to the esophagus4 ,it gives branches 7esophageal7 only to the esophagus during its passage as far as the seventh dorsal vertebra4 ,following this point there are given of several pairs of arteries which divide into a superior and an inferior branch4 ,the superior branch extends upward and anastomoses with branches of the vertebral artery and other twigs coming from the intercostal arteries4 ,these latter arteries given off are small dorsal arteries4 ,the inferior branches extend downward between the ribs and supply the intercostal muscles4 ,the intercostal arteries do not take their origin from the aorta in numerous and regular branches as in mammals2 they consist originally of but few vessels1 which are multiplied by anastomoses with each other and with the arteries which come out of the spinal canal4 ,an arterial plexus is thus formed around the head of each rib1 from which a vessel is sent to each of the intercostal muscles and ribs and are continued into the muscles upon the outside of the body and its integuments4 ,the anastomosis of the intercostal arteries round the ribs is similar to the plexus1 which is produced by the great sympathetic nerve in the same location4 ,the lumbar arteries are given off farther posteriorly and along the lumbar region4 ,the lumbar1 like the dorsal branches are given off in pairs4 ,these arterial branches pass along the thigh and the upper sacral vertebral region1 and supply those parts4 ,ventrally they are covered by the kidneys and pass into the abdominal muscles4 ,the posterior aorta gives off the spermatic arteries and the ovarian artery4 ,in the male the former supply the testes4 ,the ovarian artery of the female gives off a twig to each calyx containing an ovum4 ,each calyx is voluminously supplied with blood4 ,next the renal arteries are given off to the kidneys4 ,illustration3 ,,fig4 #fc4--,the vascular system injected4 #a1 ,the heart4 #b1 ,the posterior aorta4 #c1 ,the right brachio-cephalic artery4 #d1 ,the left brachio-cephalic artery4 #e1 ,the anterior mesenteric artery showing its many branches and anastomoses near and on the intestines4 ,it is accompanied by branches of the mesenteric vein4 #f1 ,the rectal branch of the posterior mesenteric artery4 #g1 ,the duodenal loop and pancreas showing the pancreatic artery4 #h1 ,the anus4 #i1 ,the cloaca4 #aj1 ,the liver4 #aa1 ,the lungs4 #ab1 ,the right subclavian artery4 #ac1 ,the right carotid artery4 #ad1 ,the right anterior vena cava4 #ae1 ,the subclavian vein4 #af1 ,the right jugular vein4 #ag1 ,the carotid trunk4 #ah1 ,the posterior vena cava4 ,illustration3 ,,fig4 #fd4--,the splanchnic arteries1 veins and nerves4 #a1 ,a portion of the left testes4 #b1 ,adrenal gland4 #c1 ,anterior lobe of kidney4 #d1 ,heart4 #e1 ,liver4 #f1 ,second portion of the esophagus4 #g1 ,proventriculus4 #h1 ,gizzard4 #i1 ,spleen4 #aj1 ,duodenal loop4 #aa1 ,pancreas4 #ab1 ,blind extremity of ccum4 #ac1 ,floating portion of small intestine4 #ad1 ,rectum4 #ae1 ,cloaca4 #af1 ,anus4 #ag1 ,celiac axis4 #ah1 ,ureter4 #ai1 ,vas deferens4 #bj1 ,recurrent sinister artery4 #ba1 ,anterior recurrent dexter artery4 #bb1 ,arteria hepatica dextra4 #bc1 ,recurrent esophageal artery4 #bd1 ,recurrent intestinalis artery4 #be1 ,ilio-colicus artery4 #bf1 ,anterior mesenteric artery4 #bg1 ,recurrent branches of the same4 #bh1 ,ilio-cliacus artery4 #bi1 ,recurrent superior hemorrhoidal artery4 #cj1 ,posterior mesenteric artery4 #ca1 ,crural arteries4 #cb1 ,sacralis media artery4 #cc1 ,recurrent renalis4 #cd1 ,middle renal lobe4 #ce1 ,posterior renal lobe4 #cf1 ,vena mesentericus communis4 #cg1 ,vena hemorrhoidalis4 #ch1 ,vena pancreatico-duodenalis4 #ci1 ,vena proventriculo-leinealis4 #dj1 ,vena portalis dextra4 #da1 ,ischiadic nerve4 #db1 ,thoracic sympathetic trunk4 #dc1 ,anterior splanchnic plexus4 #dd1 ,spinal nerves4 #de1 ,posterior splanchnic nerve plexus4 #df1 ,intestinal nerve trunk4 #dg1 ,vena renalis magna4 ,the celiac axis 7,fig4 #fd1 ,no4 #ag7 originates near the seventh sternal vertebra and to the right of the esophagus1 breaks through the diaphragm1 and1 near this point1 gives off a recurrent esophageal 7,fig4 #fd1 ,no4 #bc74 ,the celiac axis gives off three main branches3 ,the anterior or recurrent dexter1 the posterior or recurrent sinister1 the recurrent intestinalis1 all of which lie to the right of the spleen1 under the left lobe of the liver1 and along the left side of the stomach4 ,the recurrent sinister 7,fig4 #fd1 ,no4 #bj7 gives arterial branches to the proventriculus1 the gizzard1 the pyloris1 and the left lobe of the liver4 ,the anterior or recurrent dexter 7,fig4 #fd1 ,no4 #ba7 gives off a renal artery and from four to six splenic arteries4 ,the recurrent intestinalis artery 7,fig4 #fd1 ,no4 #bd7 arises on the posterior of the stomach within the duodenal loop1 and supplies the duodenum and the pancreas 7,fig4 #fc1 ,no4 #g74 ,it gives off a branch1 called the recurrent ilio-colicus 7,fig4 #fd1 ,no4 #be71 which supplies the large intestines1 including the cca4 ,the arteria hepatica dextra 7,fig4 #fd1 ,no4 #bb7 is a branch from the celiac axial trunk4 ,it gives several branches to the right lobe of the liver and to the gall-bladder4 ,the gastric branches pass to the muscles of the stomach4 ,the anterior and posterior recurrent branches often anastomose4 ,the anterior mesenteric artery 7,fig4 #fc1 ,no4 #e2 ,fig4 #fd1 ,no4 #bf7 originates from the posterior aorta near the generative glands4 ,it is directed downward1 and divides into many branches which pass in the mesentery toward the intestines4 ,recurrent branches 7,fig4 #fd1 ,no4 #bg7 are given off1 which anastomose1 forming mesenteric arches4 ,from these arches are given off branches which supply the intestinal walls4 ,the anterior mesenteric artery gives off the recurrent ilio-celiacus 7,fig4 #fd1 ,no4 #bh7 which is distributed to the cca2 other of its branches are distributed to the small intestine4 ,the anterior mesenteric artery extends along the small intestine and ends in the recurrent superior hemorrhoidal arteries 7,fig4 #fd1 ,no4 #bi7 which anastomoses on the surface of the rectum with a branch of the posterior mesenteric artery4 ,branches from the anterior mesenteric artery also anastomose with branches of the celiac axis4 ,the posterior mesenteric artery 7,fig4 #fd1 ,no4 #cj7 is given off from the posterior aorta posterior to the origin of the anterior mesenteric and near the arteries of the thigh and is distributed to the lesser mesentery supplying the large intestine4 ,branches of the superior hemorrhoidal arteries anastomose with branches of the posterior mesenteric artery4 ,branches from this source are called the median hemorrhoidal 7,fig4 #fc1 ,no4 #f74 ,the posterior mesenteric artery 7,fig4 #fd1 ,no4 #cj7 also gives off a long branch to the cca4 ,branches of the posterior mesenteric artery anastomose with branches of the anterior mesenteric4 ,the crural arteries 7,fig4 #fd1 ,no4 #ca7 are given off in a pair from the posterior aorta4 ,they pass through the mass of the lobes of the kidneys1 at about the median region1 and extend out of the pelvic cavity in front of the spine and ilio-pubic ligament4 ,illustration3 ,,fig4 #fe4--;,blood-vessels and nerves of the hind extremity4 ,inside view of leg4 #a1 ,ischiadic nerve4 #b1 ,ischiadic artery4 #c1 ,posterior tibial vein4 #d1 ,vena metatarsa dorsalis interna4 #e1 ,vena metatarsalis plantaris profunda4 #f1 ,vena cruralis4 #g1 ,vena metatarsalis interna1 vena magna4 #h1 ,vena tibialis postica4 #i1 ,vena metatarsa magna4 #aj1 ,nerves of the toes4 #aa1 ,vena metatarsalis dorsalis profunda4 ,the crural1 or the external iliac artery1 is divided into three branches as follows3 ,first1 the internal pelvic1 or umbilical artery1 is given off just as the cruralis leaves the pelvic cavity4 ,it passes1 as a long vessel1 on the inner surface of the lumbo-sacral bones and supplies the obturator internus muscle and extends into the umbilical region4 ,it gives off branches to the abdominal muscles1 and1 in the female1 a branch is distributed to the ligament of the oviduct4 ,second1 the arteria circumflex femoris1 which passes between the sartorius and vastus internus and extends dorsalward1 supplies the sartorius muscle1 the vasti muscles1 and the ilio-trochanteric region4 ,third1 the femoral artery1 which passes beside the vena cruralis and extends down the posterior surface of the thigh to the knee-joint1 supplies the upper thigh muscles with the exception of the adductor muscles4 ,illustration3 ,,fig4 #ff4--;,blood-vessels and nerves of the posterior extremity4 ,outside view4 #a1 ,anterior tibial artery4 #b1 ,metatarsal artery4 #c1 ,digital arteries4 #d1 ,vena cutaneous crurus4 #e1 ,ischiadic artery4 #f1 ,vena cruralis4 #g1 ,lateral cutaneous branch of the ischiadic nerve4 ,illustration3 ,,fig4 #fg4--;,blood-vessels and nerves of the fore limb4 ,outside view4 #a1 ,median nerve4 #c1 ,ulnar nerve4 #d1 ,radial artery4 #e1 ,recurrent ulnaris artery4 #f1 ,twigs of ulnar artery to wing feathers4 ,the ischiadic artery 7,fig4 #fi1 ,no4 #i7 forms the main artery of the posterior extremity4 ,this artery1 the largest vessel of that region1 is given off from the posterior aorta and passes ventrally over and between two of the main lobes of the kidney4 ,the continuation of the posterior aorta is called the sacralis media 7,fig4 #fd1 ,no4 #cb74 ,the ischiadic artery gives off a recurrent renalis on the posterior lobe of the kidney 7,fig4 #fd1 ,no4 #cc74 ,on the left side it gives off a branch to the oviduct and to the ligament of the oviduct4 ,the main trunk leaves the cavity with the ischiadic nerve 7,fig4 #fe1 ,no4 #a7 through a foramen formed by the os ilium and the os ischium4 ,it sends branches into the adductor muscles of the upper and the lower thigh4 ,it gives off anastomotic branches which unite with those from the femoral artery4 ,at the flexure of the knee-joint it gives off two branches to that region 7,fig4 #fi1 ,no4 #aj74 ,it gives off another branch to the gastrocnemius muscle and one to the flexor perforans digitorum4 ,it terminates in the anterior and posterior tibial arteries4 ,illustration3 ,,fig4 #fh4--;,blood-vessels and nerves of the fore limb4 ,inside view4 #a1 ,vena humeri profunda4 #b1 ,brachialis longus inferior4 #c1 ,brachialis profunda4 #d1 ,radial artery4 #f1 ,ulnar artery4 #g1 ,ulnar arterial branch to thumb4 #h1 ,digital branch of ulnar artery4 #i1 ,ulnar artery4 ,the first1 the tibialis postica 7,fig4 #fi1 ,no4 #ab7 passes between the gastrocnemius and the deep flexors giving off branches in its course to the skin and to other parts1 and disappears shortly below the intertarsal joint4 ,the second1 the tibialis antica 7,fig4 #ff1 ,no4 #a2 ,fig4 #fi1 ,no4 #aa71 is often the larger of the two arteries4 ,the anterior tibial artery gives off branches to the knee-joint and to adjacent structures4 ,it gives a large branch to the head of the gastrocnemius muscle4 ,it passes to the posterior surface of the tibial head and gives off the peroneal artery1 which passes through the membrana interossea located between the tibia and fibula giving branches to the anterior side of the membrane of the patellar region of the knee-joint4 ,it gives branches to the anterior side of the lower thigh and finally terminates subcutaneously in the anterior tibial plexus4 ,the main portion of the anterior tibial artery passes downward along the posterior surface of the membrane located between the tibia and fibula1 and sends branches for the flexor digitorum communis et profundus4 ,it then breaks through the membrane1 reaches the anterior side and there communicates with the anterior tibial plexus4 ,it gives off branches to the muscles on the anterior side of the lower thigh and the skin1 and passes between the outer and the middle malleolus of the tarsal bones4 ,it passes to the plantar surface and divides between the toes4 ,in addition to the plantar branches there are given off dorsal branches between the third and the fourth toes4 ,these branches form the direct continuation of the dorsal vessels of the anterior tibial plexus4 ,illustration3 ,,fig4 #fi4--;,blood-vessels and nerves of the femoro-tibial region4 ,a section of the tibia removed4 ,a4 ,veins1 arteries and nerves dissected as in ,b4 ,b4 ,v1 ,vein4 ,a1 ,artery4 ,n1 ,nerve4 #a1 ,vena poplitealis4 #b1 ,the three veins forming the vena poplitealis4 #c1 ,vena femoris interna profunda4 #d1 ,vena femoris anterior4 #e1 ,vena cruralis4 #f1 ,vena cutanea abdominalis femoralis4 #g1 ,vena cutaneous cruralis4 #h1 ,deep vein of the knee-joint4 #i1 ,ischiadic artery4 #aj1 ,branches of ischiadic artery to flexure of knee4 #aa1 ,anterior tibial artery4 #ab1 ,posterior tibial artery4 #ac1 ,ischiadic nerve4 #ad1 ,trunk 7a branch of the ischiadic7 which gives off the superficialis peroneus and peroneus profundus4 #ae1 ,median branch of ischiadic nerve4 #af1 ,superficialis peroneus4 #ag1 ,lateral branch of the ischiadic nerve4 ,the arteria pudenda communis 7,fig4 #gj1 ,no4 #bj7 passes to the depressor coccygeus muscle1 gives off a branch to the caudal part of the kidney1 crosses the ureter1 provides the ischio-pubic and pubio-coccygeus1 or depressor coccygis lateralis1 muscles1 and on the lateral rim of the latter muscle it gives off the arteria hemorrhoidalis intima4 ,this artery passes to the bursa of ,fabricius and to the end of the cloaca4 ,it enters into the ischio-coccygeus muscle1 and divides into the arteria pudenda externa1 and in ducks1 the arteria profunda penis4 ,these branches supply the vas deferens1 the ureter1 the cloaca1 the penile structure1 and the muscles of these parts4 ,illustration3 ,,fig4 #gj4--;,blood-vessels of a ,cornish cock4 #a1 ,the left pulmonary artery4 #b1 ,right pulmonary artery4 #c1 ,left brachio-cephalic artery4 #d1 ,left subclavian artery4 #e1 ,left carotid artery4 #f1 ,right brachio-cephalic artery4 #g1 ,posterior aorta4 #h1 ,posterior vena cava4 #i1 ,left pulmonary vein4 #aj1 ,right pulmonary vein4 #aa1 ,celiac axis4 #ab1 ,anterior mesenteric artery4 #ac1 ,ischiadic artery4 #ad1 ,crop4 #ae1 ,superior artery of the crop and vein of same name4 #af1 ,testicular or ovarian artery4 #ag1 ,external iliac artery4 #ah1 ,intercostal nerve4 #ai1 ,median sacral artery4 #bj1 ,arteria pudenda communis4 #ba1 ,anus4 #bb1 ,vena hypogastrica4 #bc1 ,right vena hepatica magna4 #bd1 ,left vena hepatica magna4 #be1 ,vena iliaca interna4 #bf1 ,vena iliaca communis4 #bg1 ,vena iliaca externa4 #bh1 ,vena coccygo-mesenterica4 #bi1 ,vena umbilicalis4 #cj1 ,vena suprarenalis4 #ca1 ,origin of the pars renalis4 #cb1 ,lumbar veins4 #cc1 ,vena epigastrica4 #cd1 ,lumbales 7arteries74 #ce1 ,anterior division of the lumbo-sacral plexus4 #cf1 ,posterior division of the lumbo-sacral plexus4 #cg1 ,left anterior vena cava4 #ch1 ,right anterior vena cava4 ,the ,sacralis ,media4--,the median coccygeal artery 7,fig4 #gj1 ,no4 #ai7 forms the single extension of the sacralis media4 ,it gives off lateral branches between the caudal vertebr which supply the dorsal muscles of that region and the skin4 ,the third pair are the largest4 ,these are the arteri coccyge laterales1 and are located on the dorsal side of the tail1 they supply the tail glands and rudder feathers1 the main tail feathers1 or rectrices4 ,a small arterial twig is given off to the papilla of each rectrix4 ,,the ,,venous ,,trunks ,the venous blood enters the lungs from the right ventricle through the two pulmonary arteries 7,fig4 #gj1 ,no4 #a and #b74 ,the two pulmonary veins 7,fig4 #gj1 ,no4 #i and #aj7 collect the arterial blood from the lungs1 and empty it into the left auricle4 ,there are three ven cav which collect the systemic blood and empty it into the right auricle4 ,these ven cav are two anterior 7,fig4 #gj1 ,no4 #cg and #ch7 and one posterior 7,fig4 #gj1 ,no4 #h74 ,each anterior vena cava is formed by the union of a vena jugularis1 a vena vertebralis1 and a vena subclavicularis 7,fig4 #fc1 ,no4 #ae74 ,illustration3 ,,fig4 #ga4--,veins of the liver of a fowl4 #a1 ,vena mesenterica communis4 #b1 ,vena portalis propria4 #c1 ,anterior vena mesentericus4 #d1 ,vena portalis dexter4 #e1 ,vena portalis sinister4 #f1 ,posterior vena cava4 #g1 ,celiac axis4 #h1 ,base of the heart4 #i1 ,the liver4 #aj1 ,hepatic veins4 ,the jugular vein is formed by the union of the vena cephalica anterior1 and the vena cephalica posterior4 ,the jugular vein 7,fig4 #fb1 ,no4 ,b1 #c7 passes along the side of the neck and lies near the trachea1 the esophagus1 and the pneumogastric nerve4 ,near the base of the skull the two jugular veins1 the right and the left1 are connected by a transverse vein4 ,by this anastomosis part of the blood from the left jugular vein is sent into the right4 ,therefore the right jugular vein is larger than the left4 ,the jugular veins collect the blood from the tongue region1 the thyroid1 the esophagus1 the trachea1 the crop1 and other structures along its course through the cervical region4 ,the vertebral veins are divided into the anterior and the posterior1 or the inferior and the superior4 ,the anterior vertebral vein is located in the cervical region and collects the blood from the brain and the inner part of the head4 ,the vertebral vein passes along the dorsal side of the spinal cord4 ,,branches ,,of ,,the ,,ven ,,cav ,,anteriores 7 ,ven linguales 7 ,vena occipitalis lateralis 7 ,vena occipito-collores 7 ,vena ascendenes lateralis 7 ,ven colli cutine 7 ,ven esophageale 7 ,ven tracheales 7 ,vena 7 ,vena subscapularis 7 jugularis 7 ,ven glandularum thyroidearum 7 7 7 ,vena occipitalis 7 ,sinus foraminis 7 7 7 interna 7 occipitalis 7 7 ,vena 7 7 7 vertebralis 7 ,vena vertebralis posterior 7 ,vena intercostales ,vena cava 7 7 7 ,vena vertebralis anterior anterior 7 7 ,vena vertebralis 7 ,vena vertebralis lateralis dorsalis 7 ,ven intercostales 7 7 ,ven coronari 7 ,vena subclavicularis 7 ,vena thoracica interna 7 ,vena intercostales 7 ,vena pharyngea superior 7 ,vena muscularis depressoris mandibularis ,vena facialis 7 ,vena muscularis colli anterior superioris communis 7 ,vena lingualis 7 ,vena sublingualis et sphenoidea ,the posterior vertebral vein is located in the dorsal region1 passes backward and receives the blood from the dorsal neck region and from the intercostal veins and from the vertebral segments and adjacent regions4 ,the anterior and the posterior vertebral vein form one trunk1 the vertebral vein1 and this trunk empties into the vena jugularis just before the subclavian and the jugular unite4 ,the subclavian vein collects the blood from the anterior extremities4 ,it unites with the vena jugularis of the same side4 ,the left vena cava receives the coronary veins from the heart4 ,,the ,,veins ,,of ,,the ,,head ,,branches ,,of ,,the ,,vena ,,facialis ,,interna ,the vena facialis interna 7,fig4 #fb1 ,no4 #ab7 lies dorsal on the pterygoid bone and receives the vena maxillaris1 the vena ophthalmica1 the vena mandibularis interna1 the ven pharynge superiores1 and the vena retis mirabilis temporale4 ,illustration3 ,,fig4 #gb4--;,blood-vessels and nerves of the abdominal cavity and hind extremity and head4 #a1 ,vena renalis4 #b1 ,vena intervertebrales sacrales4 #c1 ,posterior aorta4 #d1 ,external iliac4 #f1 ,ischiadic nerve4 #g1 ,ischiadic artery4 #h1 ,arterial rete 7plexus temporalis74 #i1 ,ophthalmic artery4 #aj1 ,palatine artery4 #aa1 ,lingual artery4 #ab1 ,hyoid artery4 #ac1 #ad1 ,external carotid artery4 #ae1 ,internal maxillary artery4 #af1 ,superior laryngeal artery4 #ag1 ,superior esophageal artery4 #ah1 ,occipital artery4 #ai1 ,internal carotid artery4 ,the vena maxillaris comes out of the upper beak with the recurrent trigeminus nerve and then passes backward between the jugular and palatine bones4 ,it lies medio-ventrally to the eyeball and communicates at this point with the ophthalmic vein4 ,it is covered ventrally with the pterygoid bone4 ,the maxillary vein collects the blood from the gland of ,harder1 the upper beak1 and receives blood from the vena supra-palatina and from the lower jaw bone and the external mandibular vein4 ,it also receives blood from the external sublingual vein1 and the sublingual gland4 ,it follows the inner rim of the jaw bone4 ,the maxillary vein receives an anastomosing branch from the cutaneous facial vein1 at a point near the commissure of the mouth4 ,illustration3 ,,fig4 #gc4--,photograph of blood-vessels and nerves of the thorax4 #a1 ,vena sternalis4 #b1 ,vena thoracico-externa4 #c1 ,external thoracic artery4 #d1 ,coracoid bone4 #e1 ,sternum4 #f1 ,shoulder-joint4 #g1 ,humerus4 #h1 ,clavicularis artery4 #i1 ,sterno-clavicularis artery4 #aj1 ,thoracico-humeralis artery4 #aa1 ,subclavian artery4 #ab1 ,axillary artery4 #ac1 ,brachialis profundus artery4 #ad1 ,ulnar artery4 #ae1 ,radial artery4 #af1 ,internal mammary artery4 #ag1 ,superior vein of the crop4 #ah1 ,superior artery of the crop4 #ai1 ,brachial nerve plexus4 #bj1 ,anterior division of brachial nerve plexus4 #ba1 ,posterior division of brachial nerve plexus4 ,the vena ophthalmica lies close to the point where the olfactory nerve passes out of the cranial cavity4 ,the largest branch it receives is the recurrent ophthalmo-temporalis1 which accompanies the lateral side of the optic nerve4 ,it collects the blood from the base of the brain1 from ,harder's gland1 from the eye muscles1 from the inner eye1 the nose1 the lacrimal gland1 the skin of the frontal region1 and the comb4 ,,branches ,,of ,,the ,,vena ,,jugularis 7 ,vena maxillaris 7 ,vena ophthalmica 7 ,vena facialis 7 ,vena mandibularis interna 7 interna 7 ,vena retis mirabilis temporalis 7 ,vena cephalica 7 7 ,ven pharynge superiores 7 anterior or 7 7 facialis 7 7 ,vena facialis cutinea 7 communis 7 7 ,vena temporalis 7 7 ,vena facialis 7 ,vena auricularis ,vena jugularis 7 7 externa 7 ,vena palpebralis or cephalica 7 7 ,vena transversus communis 7 7 ,vena retis mirabilis temporalis 7 ,vena subclavia 7 ,ven vertebrales 7 7 ,sinus cranii et cerebri 7 7 ,vena carotis 7 7 7 7 ,vena auris 7 ,sinus fove cerebelli 7 7 7 ,vena occipitalis externa 7 ,vena cephalica 7 ,vena jugularis prima 7 posterior 7 ,vena occipitalis 7 ,vena lingualis 7 ,vena mandibularis externa ,vena maxillaris 7 ,vena sublingualis externa 7 ,vena supra-palatina ,vena ophthalmica 7 ,vena ophthalmo-temporalis1 recurrent ,vena facialis communis 7 ,vena cephalica externa ,vena occipitalis externa 7 ,vena occipitalis interna ,vena retis mirabilis temporalis 7 ,vena spheno-temporalis ,sinus fove cerebelli 7 ,sinus occipitalis externa ,the trunk of the internal facial vein receives the blood of the internal mandibular vein4 ,the internal mandibular vein emerges from the alveolar canal of the inferior jaw bone and receives branches from the muscles of mastication4 ,the vena retis mirabilis temporalis passes out of the eye cavity and lies between the internal facial vein and the external facial vein1 and passes around the os quadratum and the os pterygoideum4 ,it receives veins from the outer ear region1 lacrimal gland1 eyelids1 and the spheno-temporalis4 ,the ven pharynge superiores are the veins on the dorsal surface of the pharynx4 ,these veins form the small plexuses which unite with the two trunks of the facial veins4 ,this forms an anastomosis between the left and the right facial veins4 ,,branches ,,of ,,the ,,external ,,facial ,,vein ,the vena facialis externa 7,fig4 #fb1 ,no4 ,b1 #i7 lies behind the quadrate bone and is partly covered ventrally by the inner extension of the lower jaw bone4 ,it collects the blood principally from the upper region of the cranium and the face1 including the comb4 ,the vena facialis cutinea receives branches from the muscles in the region of the jaw1 the lower jaw bone1 the muscles of the eyelids1 the frontal region1 and the anastomotic branches from the vena maxillaris4 ,the vena temporalis is made up of veins from the skin of the temporal region1 the masseter and the tongue muscles1 and from the sides of the upper throat region4 ,the vena palpebralis is made up from veins from the three eyelids and the temporal region near the eye4 ,its trunk passes laterally over the temporo-mandibularis ligament4 ,the vena palpebralis collects blood from the lacrimal gland1 the eyelids1 and the outer ear region4 ,the following veins empty into the trunk of the vena facialis communis3 ven pharyngis superiores1 vena muscularis depressoris mandibul1 vena muscularis colli anterior superioris1 vena lingualis et hyoidea4 ,the right terminal branches of the vena lingualis empty into the vena cephalica posterior4 ,the ven pharyngis superiores and vena lingualis et hyoidea collect blood from the muscles of the tongue and posterior tongue region4 ,the vena lingualis et hyoidea 7,fig4 #fb1 ,no4 ,b1 #g7 collects the blood from the muscles of the tongue region1 the lower tongue glands1 and the upper throat region4 ,between the two trunks of the vena facialis communis and anterior to the entrance of the vena cephalica posterior there is an anastomosis1 the vena transversus 7,fig4 #fb1 ,no4 ,b1 #e74 ,through this anastomosis which lies crosswise the two jugular veins are influenced in different ways4 ,at this point both jugular veins are of the same size4 ,the anastomotic branch lies crosswise4 ,through this anastomosis the right receives some blood from the left head region indicating that the blood flows from left to right4 ,this1 as stated before1 makes the left jugular vein the smaller4 ,,branches ,,of ,,the ,,vena ,,cephalica ,,posterior ,the left vena cephalica posterior 7,fig4 #fb1 ,no4 ,b1 #h7 communicates with the transverse vein 7,fig4 #fb1 ,no4 ,b1 #e74 ,the left receives the smaller veins of the skin region1 the esophagus1 and the trachea4 ,these vessels communicate with their fellow of the opposite side and with the vertebral vein of the same side1 which causes a gradual reduction of the size of the jugular vein4 ,,branches ,,of ,,the ,,vena ,,occipitalis ,,externus 7 7 ,ven choroide 7 ,sinus 7 ,ven cutane et frontales 7 longitudinalis 7 ,ven nasales ,vena 7 7 ,ven ophthalmi occipitalis 7 externus 7 7 7 ,sinus occipitalis 7 ,sinus 7 ,sinus 7 ,sinus temporo-sphenoideus 7 semicircularis 7 transversus 7 ,ven cerebellares 7 7 7 ,sinus petrosus sphenoideus ,sinus petrosus sphenoideus 7 ,retis mirabile temporalis ,sinus temporo-sphenoideus 7 ,sinus annularis venosus basilaris ,sinus foraminus occipitalis 7 ,ven medullares 7 ,ven cerebrales ,sinus 7 ,vena cerebralis basilaris 7 ,sinus venosus annularis anterior venosus 7 annularis 7 basilaris 7 ,vena ophthalmica 7 ,vena medullaris mediana longitudinalis ,the vena cephalica posterior 7,fig4 #fb1 ,no4 ,b1 #h7 is formed from the veins of the sinuses of the cranium1 the brain1 the vena auris1 the vena jugularis prima1 the vena carotis1 and the vena occipitalis4 ,it collects most of the blood from the cranium and the posterior part of the head and from the tongue4 ,,the ,,venous ,,sinuses ,,of ,,the ,,head ,the sinus longitudinalis 7,fig4 #fb1 ,a1 #aj7 extends from the dorsal median line of the internal occipital protuberance to the olfactory nerve4 ,it collects the blood from the choroidea of the brain and from the skin of the frontal region4 ,it receives laterally the veins of the nose1 the vena ophthalmica1 and the sinus transversus4 ,the sinus occipitalis 7,fig4 #fb1 ,no4 ,a1 #d7 forms the continuation of the transverse sinus4 ,it is located in the posterior cerebral cavity1 and is wing-shaped1 extending both to the right and to the left4 ,the sinus foraminis occipitalis a continuation of the sinus occipitalis1 lies transversely on the ventral side of the cranial cavity and receives the veins from the medulla oblongata4 ,one branch passes through the os occipitalis basilare1 and then extends sidewise to the foramen magnum and anastomoses with the vena occipitalis4 ,the sinus transversus 7,fig4 #fb1 ,no4 ,a1 #f7 extends in a pair from the internal occipital protuberance between the cerebrum1 cerebellum1 and the corpus quadrigeminum4 ,it receives vessels from the upper surface of the cerebellum4 ,the sinus has three branches1 all of which empty into the sinus semicircularis4 ,the sinus semicircularis extends along the dorsal petrosal rim1 anterior to the inner ear1 and from this point backward4 ,near the foramen magnum it passes through the os occipitale and empties into the external occipital vein4 ,the vena occipitalis externus extends near the foramen magnum1 surrounds the basis occipitalis1 and receives the semicircular sinus and through the semicircular sinus the blood from the sinus transversus4 ,the sinus petrosus sphenoideus1 passing in company with the occipital sinus1 extends from the transverse sinus to the cavity near which the trigeminus lies4 ,the sinus dividing into two branches1 one of these extends to the hypophysis and unites with the basal veins of the brain2 the other passes with the rete out of the cranial cavity along with a branch of the trigeminus1 and communicates with the rete mirabile temporale4 ,the sinus temporo-sphenoideus 7,fig4 #fb1 ,no4 ,a1 #e7 extends forward and outward from the transverse sinus1 and1 between the corpus quadrigeminum and the cerebrum1 unites with the sinus venosus annularis basilaris4 ,the sinus venosus annularis basilaris lies in the region of the optic nerve and surrounds the hypophysis1 forming a complete circle4 ,it receives small vessels from the cerebrum1 the corpora quadrigemina1 and anteriorly the longitudinal basilar vein or vena basilaris media1 of the cerebrum1 which comes out of the anterior annular venous sinus4 ,the anterior annular venous sinus surrounds the base of the olfactory nerves4 ,it communicates with the sinus petrosus sphenoideus1 which emerges from behind the optic lobe1 the sinus temporo-sphenoideus1 which emerges from in front of the optic lobe1 and posteriorly the median longitudinal vein of the medulla oblongata or vena basilaris4 ,laterally and anterior to the optic lobe it receives the vena basilaris lateralis1 and also a branch of the vena ophthalmica4 ,the blood received by the sinus annularis basilaris comes from the brain cavity through three pairs of veins1 as follows3 first1 the two ophthalmic veins which pass through the posterior orbital wall between the olfactory and the optic nerve2 second1 two other branches of the ophthalmica which pass with the optic nerve2 third1 two veins which pass through a foramen by the side of the sella turcica to the hypophysis together with the carotis cerebralis1 and then leave the cerebral cavity ventrally1 at which point they are called the ven carotes4 ,these last accompany the cerebral artery backward1 and pass through a foramen in the base of the cranium4 ,each one then passes through the cranial wall close to the external auditory canal1 and empties into another vein in the posterior region of the head4 ,the sinus fov hemispherii cerebelli lies in the hollow between the os petrosum and the semicircular canals4 ,it receives blood from the external occipital sinus and from the cerebellum1 and empties into the vena auris interna4 ,,veins ,,of ,,the ,,brain ,,cavity ,the vena auris interna passes through a bony canal along the outer rim of the posterior semicircular canal and then along the external semicircular canal4 ,it receives vessels from the labyrinth1 and extends along the posterior rim of the tympanum to the outer ear canal4 ,the vena occipitalis interna1 extending from the sinus foraminis occipitalis1 passes through the side of the atlas and divides near the condyle into two branches4 ,one of these branches the internal occipital1 forms the root of the vena vertebralis1 and the other empties into the vena occipitalis externa4 ,near the outer and upper part of the condyle it forms two large veins and collects the blood from the vena occipitalis media4 ,these veins collect the blood from the rectus capitis anticus1 and communicate with the vena cephalica anterior4 ,the vena occipitalis externa1 sometimes called the vena occipitalis collateralis1 extends from the vena auris1 and receives vessels from the neck region4 ,it receives on the side of the occipitoatloid joint the vena occipitalis interna4 ,the vena occipitalis externa forms a junction with the vena vertebralis emptying into the transverse vein4 ,,the ,,veins ,,of ,,the ,,neck ,,branches ,,of ,,the ,,vena ,,jugularis ,the trunks of the vena jugularis or vena cephalica communis pass subcutaneously on both sides near the trachea and the esophagus4 ,near the height of the thyroid gland they almost touch the carotid artery4 ,they then cross1 dorsalward1 the trunk of the subclavian artery1 and in their course receive the vertebral vein and unite with the subclavian vein toward the side of the vena brachiocephalica4 ,the union on the right side lies to the right of the anterior aorta1 and the union on the left side lies to the left of the pulmonary artery4 ,the jugular vein 7,fig4 #ah1 ,no4 #d7 receives in its course the following veins3 ,the ven linguales 7,fig4 #fb1 ,no4 ,b1 #g71 which at times empty into the vena cephalica posterior4 ,the vena occipito-collares1 which arises on the ventral side from the muscles of the neck and the vertebr2 empties into the vena occipitalis lateralis and also communicates with the vena jugularis by anastomoses4 ,the ven ascendentes laterales1 which collect blood from the lateral sides of the neck4 ,the ven colli cutine1 which enter the jugular vein laterally4 ,the upper branches are directed crosswise1 and are shorter than the lower ones4 ,the lower branches are located near the thorax1 are directed upward1 and anastomose by fine terminal twigs4 ,plexuses are frequently formed in the inner side of the skin of the neck4 ,,branches ,,of ,,the ,,vena ,,subclavia 7 ,vena profunda ulnaris 7 ,vena brachialis 7 ,vena profunda radialis 7 ,truncus ven 7 7 ,vena profunda humeri 7 axillaris 7 7 7 ,vena basilica or cutinea ulnaris 7 7 7 ,vena cutinea abdomino-pectoralis ,truncus ven 7 ,vena pectoris 7 ,vena infrascapularis anterior subclavi 7 externa 7 ,vena thoracica externa 7 ,vena coracoidea 7 ,vena sternalis ,the ven esophage are numerous smaller veins formed in closely woven plexuses in the region of the esophagus along the neck4 ,some pass upward and some downward4 ,the ven tracheales are located on the supero-lateral side of the trachea and along the edge of the lateral tracheal muscle4 ,they have numerous anastomoses transversely with the longitudinal vein of the cervical region1 anteriorly with the vena lingualis1 and on the left side with the left jugular vein4 ,the vena subscapularis passes along the median line of the scapula to the side of the jugular vein1 and anastomoses with the vertebral vein4 ,the ven glandularum thyroidearum are several small1 short veins coming from the thyroid gland4 ,the vena vertebralis1 originating near the atlas1 is a continuation of the internal occipital vein4 ,the internal occipital vein receives the bulk of the blood from the brain and communicates with the lateral veins of the cervical region and collects blood from the cervical vertebra4 ,the vertebral vein accompanies the vertebral artery and the deep sympathetic nerve trunk in the vertebral canal4 ,the vein either leaves this canal with the vertebral artery at a point near the last two vertebral nerve trunks of the brachial plexus1 or it leaves the canal one vertebra in front of the vertebral artery4 ,,the ,,veins ,,of ,,the ,,dorsal ,,region ,the vena vertebralis lateralis dorsalis collects blood from the cervical vertebr1 from the dorsal vertebr1 and from the intercostal region4 ,the blood from the neural canal1 including the spinal cord1 is collected in one long vein extending from the head to the tail on the upper side of the cord4 ,this vein has sinus-like expansions4 ,between each two vertebr it anastomoses with the vertebral vein on each side4 ,in the lumbo-sacral region these anastomotic branches empty into the hypogastric veins4 ,the vena intercostalis is formed in the costal region and anastomoses with the vein extending longitudinally between the capitulum and the tuberculum of the rib4 ,the vena vertebralis posterior at the height of the first and the second dorsal vertebr1 empties into the main trunk of the vertebral vein4 ,its lower roots come out near the side of the kidney1 and unite1 forming a large ascending trunk uniting with the vena vertebralis anterior forming one large trunk1 which extends into the chest cavity4 ,the posterior vertebral vein also receives a large vein from the skin of the outer tarsal region and a few vessels from the muscles of the outer abdominal and the outer costal region1 from the skin1 from the pectoralis muscles1 and from the shoulder region4 ,,veins ,,of ,,the ,,thorax ,,branches ,,of ,,the ,,vena ,,subclavia ,the vena thoracica externa 7,fig4 #gc1 ,no4 #b7 is made up of veins mainly from the pectoral group of muscles4 ,the posterior branch anastomoses with the vena cutinea4 ,its anterior branch is made up mainly of branches from the furcular region4 ,it empties into the vena pectoralis externa and the vena pectoralis externa empties into the vena subclavia4 ,the vena coracoidea comes out of the region of the shoulder-joint1 passes downward along the inner surface of the coracoid1 and receives small branches from the walls of the arteria brachia cephalica and from the pericardium4 ,the vena sternalis 7,fig4 #gc1 ,no4 #a7 is made up of two branches4 ,the outer branch comes from the muscles of the subclavian region passes over the cristi sterni1 medially1 to the sterno-coracoid joint and into the breast cavity1 where it receives the inner branch1 which drains the inner surface of the breast-bone4 ,the vena thoracica interna empties into the vena cava anterior4 ,it extends from the abdominal muscles where it communicates with the epigastric vein4 ,it then passes on the inner side of the thoracic cavity close to the breast-bone and receives many intercostal veins4 ,the vena cava sinistra receives first1 the vena proventricularis communis1 which collects the blood from the walls of the proventriculus1 and second1 the vena coronaria cardis magna4 ,this latter vein originates close to the apex of the heart and collects blood principally from the walls of the left ventricle4 ,it connects in the left sulcus transversus with the vena cardis superior and ends at the base of the left upper vena cava4 ,its exit is not guarded by a valve4 ,the veins of the right ventricle are partly on the surface4 ,they collect blood along the sulcus transversus dexter and enter directly into the right ventricle4 ,the veins of the front part of the heart are small4 ,they collect behind the sulcus coronalis and end either directly into the right auricle or into the vena cardis magna4 ,,veins ,,of ,,the ,,fore ,,limb ,the vena radialis profunda accompanies the radial artery on the dorsal anterior rim of the index-finger and passes1 on the dorsal side1 over the carpal region4 ,it passes through the interosseous ligament between the ulna and the radius1 and reaches the ventral surface of the arm4 ,at this point it passes upward and anastomoses with the vena ulnaris4 ,it collects the blood from the skin of the anterior wing region and the flexor muscles of the anterior arm4 ,it empties into the vena brachialis4 ,the vena humeri profunda 7,fig4 #fh1 ,no4 #a7 emerges at the height of the elbow1 and collects blood from the skin of the dorsal surface of the wing4 ,it also receives veins from the muscles of the posterior side of the upper arm4 ,it passes subcutaneously and dorsally over the dorsal portion of the humerus in company with the external radial muscle and passes with it around the external part of the humerus between the long and short heads of the triceps4 ,it takes a diagonal course to the shoulder cavity and at that point empties into the brachial trunk4 ,the profundus ulnaris originates at the volar surface of the hand1 proceeds in company with the ulnar artery1 and sends on the base of the hand small anastomotic veins to the vena cutanea ulnaris or basilica4 ,it passes along the anterior arm and between the flexor carpi ulnaris and the pronator profundus muscle to the elbow-joint4 ,on the median surface of the biceps it passes upward and anastomoses with the radial vein4 ,the ulnar vein1 in the region of the elbow-joint1 receives a large lateral branch which extends around the end tendon of the biceps and anastomoses above with the vena basilica4 ,the vena basilica or cutanea ulnaris is a long vein which originates from the subcutaneous dorsal surface of the index-finger4 ,near the base of the hand it receives an anastomosing branch from the vena radialis and the vena ulnaris1 and then passes upward along the posterior rim of the ulna4 ,it receives numerous branches from the roots of the flight feathers4 ,it crosses below the elbow-joint and reaches the volar surface of the arm4 ,it receives a large branch from the ulnar vein1 and then1 passing in a diagonal and median direction to the triceps1 extends to the shoulder cavity where it empties into the axillary vein4 ,the outer breast veins unite forming a trunk which crosses ventrally to the subclavian artery1 and empties into the subclavian vein4 ,the vena cutanea abdomino-pectoralis collects the blood from a large skin area of the abdomen1 the upper thigh1 the breast1 and the intercostal region4 ,in the skin of the abdomen it forms a network4 ,,branches ,,of ,,the ,,iliacs 7 ,vena metatarsalis 7 ,vena metatarsalis 7 ,vena 7 interna or magna 7 plantaris profunda 7 tibialis 7 ,vena tibialis antica 7 postica 7 ,vena metatarsalis 7 ,ven metatarsales 7 7 externa 7 7 ,vena 7 ,vena metatarsalis dorsalis profunda 7 ,vena 7 tibialis 7 ,vena metatarsalis dorsalis interna 7 poplitealis 7 antica 7 ,vena peronealis 7 7 ,vena cutanea cruralis 7 7 ,ven surales ,vena 7 iliaca 7 7 ,vena cutanea abdominalis femoralis externa 7 ,vena 7 ,vena femoralis interna profunda 7 cruralis 7 ,vena femoralis anterior 7 7 ,vena epigastrica ,the main trunk passes in the median abdominal line forward and then upward1 along the outer edge of the pectoralis major1 over the first sternal rib2 receives blood from the infrascapular vein1 and empties into the pectoralis externa4 ,the vena brachialis is located in the middle of the humerus and the triceps muscle4 ,it is formed by the vena ulnaris1 and the vena radialis4 ,it passes with the median nerve and the brachial artery over the inner surface of the humeral joint4 ,posterior to the humeral head it receives the vena profunda humeri4 ,at the shoulder cavity it receives the vena cutanea ulnaris or vena basilica4 ,the trunk of the axillary vein is very short and is formed by the veins of the shoulder and the wing4 ,the deeper wing veins accompany the large arterial and the nerve trunks4 ,,branches ,,of ,,the ,,vena ,,iliaca ,,interna 7 ,vena intervertebralis lumbalis 7 ,pars truncalis 7 ,vena renalis magna 7 7 7 7 7 ,vena hypogastrica caudalis sinistra 7 7 ,vena renalis 7 ,vena hypogastrica caudalis dextra 7 7 7 ,vena portalis 7 7 ,vena coccygea 7 ,vena cutanea et pudenda ,vena iliaca 7 7 ,vena coccygea mesenterica interna or 7 7 ,vena cutanea pubica vena hypogastrica 7 ,pars caudalis 7 ,vena cutanea caudalis 7 7 ,vena pudenda 7 ,vena spermatica 7 7 ,vena caudalis muscularis 7 7 ,ven sacrales 7 7 ,ven intervertebrales sacralis 7 ,ven renales 7 7 ,ven renales 7 ,pars renalis 7 ,vena ischiadica 7 ,vena obturatoria 7 ,vena suprarenalis externa 7 ,azygos sacralis ,,the ,,posterior ,,vena ,,cava ,the posterior vena cava 7,fig4 #fc1 ,no4 #ah2 ,fig4 #gj1 ,no4 #h7 has its origin in the posterior half of the body of the bird1 somewhat to the right of the posterior aorta1 near the anterior lobe of the kidney1 by the union of the right and the left vena iliaca communis4 ,it receives the blood from all of the posterior half of the body including the posterior limbs1 of the visceral organs1 of the abdominal and the pelvic cavity4 ,the posterior vena cava passes dorsally through the right lobe of the liver and through the diaphragm and ends in a short1 broad trunk on the posterior dorsal side of the right auricle of the heart4 ,its opening into the heart is guarded by two half-moon shaped valves4 ,the basal part of the trunk reaches from the right auricle of the heart to the upper anterior rim of the liver where it receives three large trunks1 first1 the right and second1 the left vena portalis hepatica magna1 and third1 smaller vessels from the liver substance4 ,,the ,,veins ,,of ,,the ,,posterior ,,extremity ,in the skin region on the inner sides of the toes near their bases the small veins collect into five metatarsal veins4 ,the largest vein collects the blood from the first1 the second1 and the third toe1 passes up the tarsus and is called the vena metatarsalis interna1 or vena magna 7,fig4 #fe1 ,no4 #g74 ,it is located just beneath the skin on the inner surface of the metatarsal bone4 ,it passes in a circle1 around the condyle of the tibia and becomes the vena tibialis postica 7,fig4 #fe1 ,no4 #c and #h74 ,the vena tibialis postica passes under the tendon ,achillis and the tendon of the flexor digitorum brevis1 lies subcutaneously upon the latter1 and reaching the knee-joint crosses over the upper surface of the ischiadic nerve and becomes the vena poplitealis1 at which point it receives the vena tibialis antica4 ,,branches ,,of ,,the ,,vena ,,cava ,,posterior 7 ,vena ovariana 7 ,ven testicul 7 ,vena proventricularis communis 7 ,vena suprarenalis revehentis 7 ,vena portalis magna sinistra 7 ,vena portalis magna dextra 7 ,ven innominat 7 ,ven hepatic ,vena cava 7 ,vena cardis coronaria magna posterior 7 ,vena proventricularis inferior 7 7 ,vena iliaca interna 7 ,vena hypogastrica 7 7 ,vena iliaca externa 7 ,vena renalis 7 7 ,vena suprarenalis externa 7 ,vena iliaca 7 ,vena ischiadica 7 communis 7 ,vena renalis 7 7 ,vena intervertebralis lumbalis 7 7 ,vena renalis magna 7 ,vena mesenterica communis 7 ,vena coccygo-mesenterica ,vena 7 7 ,vena mesenterica anterior portalis 7 ,vena pancreatico-duodenalis dextra 7 7 ,vena proventricularis 7 ,vena proventricularis lienalis 7 ,vena splenica ,vena coccygo-mesenterica 7 ,vena hemorrhoidalis ,on the dorsal side of the metatarsus are two veins4 ,the vena metatarsalis dorsalis profunda 7,fig4 #fe1 ,no4 #aa71 which extends under the tendon of the extensors of the toes1 along with the artery and the nerve4 ,it collects the blood from the third and the fourth toe and in the middle of the metatarsus receives the vena metatarsalis dorsalis interna 7,fig4 #fe1 ,no4 #d71 which connects the vena metatarsalis dorsalis profunda and the vena magna4 ,the two dorsal veins anastomose with the vena magna1 at the intertarsal joint4 ,they pass transversely under the ligament and form the main trunk of the vena tibialis antica which lies close to the anterior surface of the tibia4 ,near this point there is formed a plexus of veins which again form a trunk and communicates with the vena peronealis and enters between the tibia and fibula with the tibialis antica4 ,it extends along the flexure of the knee and the posterior part of the lower thigh4 ,the vena metatarsalis externa passes subcutaneously on the outside of the fourth toe and the metatarsus1 and above the intertarsal point joins the tibialis postica4 ,the vena metatarsalis plantaris profunda 7,fig4 #fe1 ,no4 #e7 lies on the ventral side of the foot and forms several anastomosing arches with the other veins of the toes4 ,below the intertarsal joint it enters the vena metatarsalis magna 7,fig4 #fe1 ,no4 #i74 ,the vena cutanea cruralis 7,fig4 #fi1 ,no4 #g7 originates at the height of the tarsal region and passes subcutaneously on the outer posterior surface of the lower thigh region to the vena poplitealis4 ,the ven surales or inferior muscular branches of the vena poplitealis consist of many veins4 ,one branch comes from the region of the shank and from the gastrocnemius muscle2 another as a main branch from the posterior surface of the lower thigh2 and a third from the outer surface of the muscles and skin of the upper thigh4 ,the three branches together with the anterior and posterior tibial 7,fig4 #fi1 ,no4 #b7 unite at the flexure of the knee forming the vena poplitealis 7,fig4 #fi1 ,no4 #a74 ,in the region of the upper thigh1 between the knee and the abdominal cavity1 the following four veins form the vena cruralis3 7,fig4 #ff1 ,no4 #f2 ,fig4 #fi1 ,no4 #e74 ,first1 the vena cutanea abdominalis femoralis 7,fig4 #fi1 ,no4 #f7 which comes out of the side of the abdominal wall1 draining the skin of the inner surface of the upper portion of the thigh1 the adductor muscles1 and the region of the abdominal and the breast border4 ,it crosses the ischiadic artery in a diagonal direction1 and enters the vena cruralis in the middle of the crural region4 ,second1 the vena femoralis interna profunda 7,fig4 #fi1 ,no4 #c7 forms a communication between the end of the suralis near the knee4 ,it lies on the median portion of the flexor cruris internus muscle4 ,third1 the vena femoralis anterior 7,fig4 #fi1 ,no4 #d7 is formed from branches from the sartorius and adjacent structures1 and anteriorly empties into the crural vein near where the latter enters the abdominal cavity4 ,fourth1 the vena epigastrica 7,fig4 #gj1 ,no4 #cc7 is formed by branches from the abdominal wall and branches from the walls of the abdominal air-sacs4 ,it passes along the median surface of the os pubis and ends into the vena cruralis near the spine of the ilio-pubica or at a point where these join with the vena hypogastrica4 ,,veins ,,of ,,the ,,caudal ,,region ,,and ,,of ,,the ,,pelvic ,,cavity ,the vena iliaca interna or the vena hypogastrica 7,fig4 #gj1 ,no4 #bb7 collects most of the blood from the tail4 ,the vena iliaca interna collects most of the blood from the pelvic cavity1 and the adjacent intestines4 ,it unites with the vena iliaca externa 7,fig4 #gj1 ,no4 #bg7 and receives the vena renalis magna and forms the trunk of the vena iliaca communis 7,fig4 #gj1 ,no4 #bf74 ,the vena coccygea originates between the coccygeal vertebr1 and collects the blood from the region of the tail1 including the tail feathers1 the tail muscles1 the tail gland1 and the skin of the region4 ,these small collecting vessels form a trunk on each side of the coccyx4 ,the right and the left pass laterally1 each one taking up a vena cutanea et pudenda1 and frequently anastomosing with the vessels on the other side4 ,these often unite into one vessel4 ,both trunks are connected by a transverse1 or anastomotic1 vessel4 ,at this anastomosis there empty into it the vena coccygea mesenterica and the vena portalis4 ,there also communicate at this point the right and the left hypogastrica caudalis4 ,in its course it is partly imbedded in the kidney and passes anteriorly to the vena iliaca communis4 ,this circle is called the arcus hypogastricus4 ,thus the veins of the abdominal cavity have many anastomoses forming many arcs1 making possible two outlets for the blood4 ,the azygos sacralis empties into the arcus at about its middle4 ,from here it extends forward to the inside and under the kidney and empties into the vena suprarenalis externa4 ,the vena cutanea pubica originates on the lower portion of the abdomen1 collects the blood from the muscles of the distal part of the ischium1 and enters the pelvic cavity between the ischium and the ilium4 ,it joins with the vena cutanea caudalis4 ,the vena cutanea caudalis originates from branches which drain the skin and other parts of the ventral coccygeal region4 ,the vena cutanea pubica also communicates with the vena caudalis muscularis and with the vena pudenda1 thus forming the caudal trunk of the vena hypogastrica4 ,the vena pudenda originates in the walls of the cloaca in the region of the generative organs4 ,a small vena spermatica accompanies the lower end of the vas deferens and the ureter1 and empties medially into the vena pudenda4 ,the pars renalis of the vena hypogastrica extends from the middle of the arcus to the union of the vena hypogastrica and the vena cruralis4 ,the vena hypogastrica communicates with the pars renalis4 ,the vessels that empty into the pars renalis are as follows3 ,the ven sacrales collect blood from the dorsal wall of the abdominal cavity and enter the pelvis through the foramen sacralis4 ,they pass between the pelvic wall and kidney1 and at times pass through the kidney tissue4 ,they empty into the pars renalis of the hypogastric arch4 ,the ven intervertebrales sacrales 7,fig4 #gb1 ,no4 #b7 originate in the region of the roots of the plexus of sacral nerves and pass through the kidney substance or on the dorsal surface and empty into the pars renalis4 ,the ven renales 7,fig4 #gb1 ,no4 #a7 are very numerous and originate in the kidney substance1 forming two main and several minor branches1 which pass posteriorly1 and empty partly into the vena hypogastrica1 partly into the vena renalis magna1 and also into the vena intervertebralis2 other branches empty into the trunk of the iliaca communis4 ,the vena suprarenalis externa 7,fig4 #gj1 ,no4 #cj7 is located near the anterior rim of the kidney and is connected with the vena hypogastrica4 ,it also receives on the medial side1 short branches which come out of the upper kidney surface and sacral vertebr4 ,the vena ischiatica originates by the union of several venous branches which come from the muscles of the pelvis and upper thigh region4 ,the ischiatic vein enters the pelvic cavity along with the ischiatic nerve and artery1 and communicates with the vena hypogastrica at about the level of the anterior lobe of the kidney4 ,it is always smaller than the vena cruralis4 ,the vena obturatoria originates mainly from vessels from the obturator muscles4 ,it enters the pelvic cavity through the obturator foramen4 ,another branch is sometimes found which comes out of the inner surface of the peritoneum which covers the obturator muscles and the walls of the abdominal air-sacs and empties between the vena ischiatica and the vena vertebralis into the vena hypogastrica4 ,,veins ,,of ,,the ,,truncus ,,vena ,,iliaca ,,communis ,the vena intervertebralis lumbalis1 which comes out of the lumbar region1 the spinal canal1 the lumbo-sacral nerve plexus1 and several small venous branches from the lobes of the kidney4 ,it passes dorsalward through the kidney and empties into the iliac vein4 ,there are also communications with the vena intervertebralis thoracica4 ,the vena renalis magna 7,fig4 #fd1 ,no4 #dg7 forms the main descending vein to the middle and posterior lobes of the kidney4 ,it lies ventrally and mesially on the middle lobe and partly on the inner part of the posterior lobe4 ,it sometimes has on each side two main trunks4 ,the vein receives some small vessels out of the anterior kidney lobe1 also other small veins from that part of the peritoneum which covers the kidney1 from the rectum and finally small veins from the ureter4 ,,visceral ,,veins ,,of ,,the ,,posterior ,,vena ,,cava ,the ven testicul1 or the vena ovariana drain the blood from the testicles of the male and ovary of the female4 ,the size of these veins change with the enlargement of the testes or of the ovary during reproductive activity4 ,the ven suprarenales revehentes are short1 thick trunks coming from the adrenal glands4 ,the left empties into the left side of the posterior vena cava and the right into the right dorsal side4 ,these receive veins from the testicles in the male and from the ovary in the female4 ,the vena proventricularis inferior drains the stomach wall4 ,one branch of this vein enters the left side of the posterior vena cava2 the other enters the vena proventricularis communis1 which in turn empties into the trunk of the anterior vena cava sinistra4 ,the ven hepatic consist of one large and several small veins from each lobe of the liver1 and empty into the posterior vena cava4 ,some small vessels come from the pericardium and the peritoneal covering of the liver1 and pass in the mediastinum to the trunk of the posterior vena cava4 ,in the region of the vena portalis3 ,the liver receives almost all the blood from the stomach1 the intestines1 the pancreatic gland1 the spleen1 partly from the liver itself1 and partly from the abdominal air-sacs4 ,this blood enters into the liver through the vena portalis dextra1 the vena portalis sinistra1 and the vena portalis propria4 ,in both lobes of the liver these veins divide into numerous small branches and collect again into two large short trunks1 the vena hepatica magna dextra 7,fig4 #gj1 ,no4 #bc71 coming out of the right lobe of the liver and the vena hepatica magna sinistra 7,fig4 #gj1 ,no4 #bd7 coming out of the left lobe4 ,these two vessels empty inferiorly into the posterior vena cava4 ,the vena portalis dextra receives the blood from the vena mesenterica communis4 ,the vena mesenterica communis 7,fig4 #fd1 ,no4 #cf7 receives the blood from the vena coccygo-mesenterica 7,fig4 #gj1 ,no4 #bh7 which comes from the arcus hypogastricus and receives the vena hemorrhoidalis 7,fig4 #fd1 ,no4 #cg74 ,this drains the cloaca and the bursa of ,fabricius1 and it also receives veins from the rectum and from the base of the cca4 ,the vena mesenterica anterior 7,fig4 #ga1 ,no4 #c7 accompanies the anterior mesenteric artery1 and collects the blood from numerous vessels from the small intestine4 ,the vena pancreatico-duodenalis 7,fig4 #fd1 ,no4 #ch7 comes out of the duodenum and the pancreas1 along the right side of the stomach and along both cca4 ,the vena proventriculo-lienalis 7,fig4 #fd1 ,no4 #ci7 comes out of the dorsal side of the proventriculus on the left side of the gizzard1 passes along the hilus of the spleen1 and takes up several splenic veins4 ,the vena portalis dextra 7,fig4 #fd1 ,no4 #dj2 ,fig4 #ga1 ,no4 #d7 receives a vein near the base of the gall-bladder4 ,this branch enters the right lobe of the liver and unites with the vena portalis sinistra4 ,the vena portalis sinistra 7,fig4 #ga1 ,no4 #e7 enters the left lobe of the liver and there forms a sinus4 ,it receives vessels which come from the muscles of the gizzard1 the inferior vena proventricularis1 and from the proventricular wall4 ,the vena portalis propria receives small veins which come out of the walls of the abdominal air-sacs and from the fat of the abdominal walls4 ,the vena umbilicalis originates in the umbilical region and empties into the vena hepatica magna sinistra at a point where it comes out of the liver 7,fig4 #gj1 ,no4 #bi74 ,this is the remains of an embryonal vein which collected all the blood of the yolk sac1 passed on the left side of the large intestine to the body1 took up the vena mesenterica and ended as the vena umphalo-mesenterica4 ,,the ,,lymphatic ,,system ,the peculiarity of the lymph vessels is that they are associated with organs in which lymph cells are formed4 ,the lymphatic system consists of the lymph vessels and the cell-forming organs4 ,in some instances the cell-producing organs are lymph follicles and in others lymph glands4 ,for the most part the glands are replaced by plexuses which in many places surround the blood-vessels4 ,the lymph of birds is similar to that of mammals4 ,the larger lymph vessels are similar to the veins1 although the walls are always thinner4 ,its tunica intima is rich in elastic fibers and has a layer of endothelial cells on the inner side4 ,the tunica media is formed of rings of smooth muscle fibers4 ,the adventitia is composed of loose connective tissue4 ,the lymph vessels frequently form plexuses4 ,the large lymph trunks follow the course of the larger blood-vessels1 and frequently surround the arteries4 ,all the lymph vessels of the body1 exclusive of the lymph of the caudal region1 form into a large trunk which originates on both sides of the celiaca communis and passes upward along the side of the abdominal aorta1 reaching a point anterior to the celiaca4 ,by receiving many vessels in this region it forms a plexus around the aorta1 and finally divides into two vessels1 the right and the left1 ducti thoracici4 ,the lymph vessels of the left side of the head1 the neck1 and the lung1 and the left wing1 and also lymph vessels of the proventriculus and the throat enter into the left ductus thoracicus4 ,they accompany the jugular vein and are closely associated with the thyroid gland4 ,the right thoracic duct receives the lymph veins from the right cervical lymph vein1 and the right side of the head1 the neck1 the lung1 and from the right wing4 ,after the right cervical lymph vein has passed through the right thyroid gland1 it divides into two branches1 one branch emptying into the right thoracic duct and the other into the vena cava dextra4 ,the lymph vessels of the liver1 the stomach1 the pancreas1 and the duodenum enter near the root of the arteria celiaca into the large lymph trunk4 ,the lymph vessels of the remainder of the intestines1 of the kidney1 and of the generative organs empty farther caudally4 ,the lymph vessels of the intestines take up the emulsified fat4 ,this emulsion in birds is colorless4 ,the vessels pass upward along the mesenteric arteries4 ,there are no mesenteric glands4 ,these vessels form a plexus around the arteria celiaca4 ,the lymph vessels of the posterior extremities accompany the artery1 especially the anterior iliaca externa1 and empty into the thoracic duct at the point of the anterior iliaco-communis4 ,the lymph vessels in birds are numerous4 ,the lymph glands are few4 ,they are only visibly found in the anterior breast and the neck region1 and sometimes in the wings4 ,lymph follicles are numerous in the intestines4 ,the thin walls of the lacteals1 of the lymph vessels1 and of the thoracic duct are made up of two tunics1 the inner being the thinner and weaker4 ,the lymphatics of the foot unite to form the vessels along the sides of each toe4 ,in palmipedes there are anastomosing branches which pass from the lateral vessels of one toe to those of the adjoining toe1 forming arches in the uniting web of the foot4 ,these branches form a small plexus at the anterior part of the digito-metatarsal joint1 from which pass three or four lymph vessels4 ,the anterior and internal branches accompany and form a network around the blood-vessels4 ,the posterior and external branches receive the lymphatic vessels from the sole of the foot4 ,they then ascend along the metatarsus and form1 at its proximal articulation1 a close network from which vessels pass along the tibial region1 forming a plexus around it as far as the middle of the leg4 ,from this there arises two branches4 ,the smaller passes along the anterior part of the depression between the tibia and the fibula1 as far as the knee-joint1 where it joins the other branch1 which accompanies the blood-vessel4 ,the trunk formed by the union of these two vessels accompanies the femoral vessels4 ,forming plexuses in its course1 it receives tributary vessels from the adjacent muscles4 ,the iliac trunk accompanies the femoral vein into the abdominal cavity1 entering just in front of the anterior end of the pubis4 ,at this point it receives branches from the lateral parts of the pelvis and then separates into two branches4 ,the posterior vessel receives some lymph from the anterior lobes of the kidney1 and from the ovary1 or testis1 and communicates anteriorly with a branch formed by the lymph vessels adjacent to the anterior mesenteric artery1 and posteriorly with a large vesicular plexus surrounding the aorta and its branches4 ,this plexus receives the lymph from the renal plexus and from those accompanying the arteria media4 ,there are two sacral or pelvic vesicles which are situated at the angle between the tail and the thigh in the posterior part of the abdominal cavity4 ,each vesicle is a trifle more than a half inch long and a quarter inch wide1 and is shaped somewhat like a kidney bean4 ,they have muscular coats with striated fibers4 ,these sacs are called 8lymph hearts40 ,the anterior division of the femoral lymphatic trunk accompanies the aorta1 on which it forms a plexus with the branches of the opposite side1 and with the intestinal lymph vessels4 ,these vessels commence from a continuous plexiform network located between the mucous and the muscular coat of the intestine4 ,they are larger at this point than where they leave the intestine to pass through the mesentery4 ,they accompany the trunk of the anterior mesenteric artery and form a plexus around it4 ,before reaching the region of the aorta1 the intestinal lymphatic vessels communicate with the posterior division of the femoral trunk and with the lymph vessels of the ovary or of the testis4 ,after passing to the region of the aorta they receive vessels from the pancreas and the duodenum1 and terminate around the celiac axis with the lymphatics of the liver1 the proventriculus1 the gizzard1 and the spleen1 forming a rather voluminous plexus 7,lauth74 ,the aortic plexus represents the receptaculum chyli and gives origin to two thoracic ducts1 mentioned above1 which passing on each side of the bodies of the vertebr1 pass one right and one left1 over the lungs1 from which they receive lymph vessels1 and terminate after receiving the lymph vessels of the wing1 into the jugular vein of their respective sides4 ,the left thoracic duct1 before emptying into the vein1 receives the trunk of the lymphatics of the left side of the neck1 and the right duct that of the right side of the neck1 each tributary collecting lymph from all the structures of its side4 ,the lymphatics of the wing follow the course of the brachial artery1 forming a plexus around it4 ,these vessels are well developed in the elbow region4 ,the principal trunk1 following the humerus1 receives collateral branches in its upper third4 ,this vessel1 when nearing the chest1 receives two or three large lymph vessels from the pectoral muscles1 and a branch which accompanies the brachial plexus4 ,the lymph vessels of the head accompany the branches of the jugular vein1 collecting the lymph from the structures of the head and the neck4 ,the lymphatic vessels communicate at the anterior and posterior oblique anastomosing vessels4 ,at the lower part of the neck each trunk receives a vessel1 which accompanies the carotid arteries4 ,further on they are provided with a lymph gland which rests on the jugular vein4 ,,the ,,blood ,,and ,,its ,,functions ,the special function of the blood is to nourish all the tissues of the body1 and in this way to aid growth and repair4 ,it furnishes material for the purpose of the elaboration of body secretions2 it supplies the organism with oxygen2 and it carries away carbon dioxid and other effete material4 ,blood is constantly in circulation4 ,blood is red1 opaque1 and is1 in the fowl1 quite viscid4 ,the exact tint of the blood depends on whether it is drawn from an artery or from a vein4 ,blood from a vein has a purplish tinge while that from an artery is a bright scarlet4 ,the color of blood is largely due to pigment in the erythrocyte1 called hemoglobin4 ,the reaction of the blood is alkaline1 due to the phosphate and the bicarbonate of soda4 ,the alkalinity of the blood is reduced by work4 ,this is due to the formation of sarcolactic acid in the muscle4 ,the odor of blood is due to volatile fatty acids4 ,each kind of fowl has its own peculiar odor4 ,the taste of the blood is saltish1 due to a small amount of sodium chlorid it contains4 ,the blood consists of the following substances3 ,first1 the unorganized part1 or fluid1 the liquor sanguinis or plasma4 ,it contains in solution proteids1 extractives1 mineral matter1 and gases4 ,the gases are held in loose chemical union4 ,the liquor sanguinis constitutes fully #ff per cent4 of the volume of the blood4 ,it is albuminous in nature and contains a small amount of coloring matter of a fatty nature4 ,it holds in solution three proteids--fibrinogen1 serum globulin1 and serum albumin4 ,second1 the organized parts1 or the cellular structure 7,fig4 #gd1 ,nos4 #a to #ba74 ,the cells float in the plasma and consist of three groups3 the erythrocytes1 or red blood cells1 the leucocytes1 or white blood cells1 and the thrombocytes4 ,erythrocytes4--,the average number of red cells 7,fig4 #gd1 ,no4 #ba7 of the domestic fowl range between #c1jjj1jjj and #d1jjj1jjj per cubic millimeter4 ,the red blood cells are flattened and elliptical in shape1 and possess an oval elliptical nucleus4 ,the average length is inch and the diameter inch1 or #g to #h micra in diameter and #ab to #ac micra in length4 ,however the diameters vary in different kinds of birds4 ,the cytoplasm is yellow and glassy1 and the nucleus takes basic stains and appears somewhat picnotic4 ,thrombocytes4--,the thrombocyte 7,fig4 #gd1 ,no4 #ai7 is of about the same length as the erythrocyte but somewhat narrower4 ,the nucleus is round1 stains purple with the ,wright's stain1 and the chromatin material is somewhat diffused4 ,the diameter of the nucleus is nearly equal to that of the cell4 ,the cytoplasm is pale and may show vacuoles near the nucleus4 ,they may contain small circumscribed red structures4 ,they vary somewhat in size and shape4 ,there are in the domestic fowl between #de1jjj and #ee1jjj per cubic millimeter4 ,leucocytes4--,there are1 in the blood of the hen1 #bh1jjj to #ce1jjj leucocytes per cubic millimeter4 ,the leucocytes may be divided into five distinct types4 ,these are as follows3 ,polymorphonuclear leucocytes with eosinophilic rods 7,fig4 #gd1 ,no4 #b7 are round and have a diameter about equal to the length of the erythrocyte4 ,the nucleus is polymorphous2 that is1 it has two or more lobes4 ,the nucleus stains a pale blue1 and the chromatin is diffused4 ,the cytoplasm is colorless with bright red staining spindle-shaped rods4 ,there are #bh to #cb per cent4 of this type of cell in the blood of the hen4 ,illustration3 ,,fig4 #gd4--;,blood cells of the fowl4 ,wright's stain4 ,from a ,s4 ,c4 ,rhode ,island ,red cockerel4 #a1 ,basophile 7mast cell7 with lilac staining spherical granules4 #b1 ,eosinophile with rod-shaped acidophile bodies4 #c and #d1 ,eosinophiles with acidophile staining round granules4 #e1 ,eosinophile ruptured4 #f1 ,mononuclear leucocyte with vacuoles in the cytoplasm4 #g and #i1 ,transitional leucocytes 7first stage74 #h1 ,mononuclear leucocyte4 #aj1 #aa1 and #ab1 ,small lymphocytes4 #ac and #ad1 ,large lymphocytes4 #ae1 ,a lymphocyte4 #af1 ,lymphocyte 7nucleus centrally located74 #ag and #ah1 ,transitional leucocyte4 #ai1 ,thrombocyte4 #bj1 ,neutrophile 7polymorphonuclear74 #ba1 ,erythrocytes4 ,polymorphonuclear leucocytes with eosinophilic granules 7,fig4 #gd1 ,no4 #c and #d7 are of about the same shape and size as the preceding4 ,the nucleus is similar to the former except that it may appear slightly picnotic4 ,the cytoplasm stains not at all or faintly blue2 it contains round or spherical granules which stain a dull red4 ,there is from #d to #f per cent4 of this type of eosinophiles found in the domestic fowl4 ,lymphocytes are round in shape and of about the diameter of the width of a thrombocyte 7,fig4 #gd1 ,no4 #aa74 ,the nucleus is round1 staining somewhat purple1 and contains a diffused chromatin material4 ,the cytoplasm exists in only small amounts2 it lies to the side of the nucleus and stains a pale blue4 ,this is the small lymphocyte4 ,a similar cell but much larger also exists4 ,this is the large lymphocyte 7,fig4 #gd1 ,no4 #ac74 ,there is from #dj to #dd per cent4 of the lymphocytes in the blood of the fowl4 ,the small lymphocytes are most abundant4 ,large mononuclear cells 7,fig4 #gd1 ,no4 #f7 either round or oval1 in shape1 whose diameter may be about that of an erythrocyte and at times much larger4 ,the nucleus may be round1 oval1 or irregular1 and at times rather crescent or ,u-shaped 7,fig4 #gd1 ,no4 #ag74 ,the cytoplasm is abundant and completely surrounds the nucleus4 ,the cytoplasm stains a paler blue than the nucleus4 ,both taking the basic stain as do the lymphocytes4 ,these constitute #ah to #bj per cent4 of the cells of the blood4 ,mast cells or basophiles 7,fig4 #gd1 ,no4 #a7 are of about the same size and shape as the eosinophiles4 ,the nucleus is round or oval1 and stains a very pale blue4 ,the cytoplasm is colorless1 mostly to one side of the nucleus1 and contains round or spherical purple staining granules4 ,this type of cell constitutes from #b to #d per cent4 of the white cells of the blood4 ,structure of the ,red ,blood ,cell4--,the red blood cell is composed of a spongy stroma holding in its meshes the red coloring matter4 ,the stroma1 or framework1 of the erythrocyte consists principally of nucleo-albumin2 it contains lecithin1 cholesterin1 and salts4 ,the red matter consists of an albuminous crystalline substance called hemoglobin1 which forms about #ij per cent4 of the total solid matter of the dried corpuscle4 ,each red cell offers a certain absorbing surface for oxygen4 ,as the blood circulates through the delicate walls of the lungs and the air-sacs1 it takes up oxygen2 the blood at the same time delivers to the air carbon dioxid which has been brought from the tissues where active cell metabolism has been going on4 ,this oxygen taken up by the erythrocyte forms a loose chemical union and is known as oxy-hemoglobin4 ,in this form it is carried to the tissues of the body where it is given up by the erythrocyte to the tissues where oxidation is going on4 ,hemoglobin is a crystallizable proteid substance containing carbon1 hydrogen1 oxygen1 nitrogen1 sulphur1 and iron4 ,formation of the ,cells of the ,blood4--,the red blood cells are formed in the red marrow of the bone4 ,polymorphonuclear leucocytes are formed in the red marrow of the bones1 and the lymphocytes in the lymph glands and lymph follicles4 ,the bird carries a normal body temperature of #aje to #ajg ,f4 ,the average temperature of #ej mature hens and cocks was #ajf4h ,f4 ,the blood is of a deep red color4 ,composition of the ,blood4--,the average composition of the blood of the domestic fowl as given by ,owen1 is as follows3 ,whole shed blood3 ,water #ghj parts ,clot #aeg parts ,albumin and salts #fc parts ---------- #ajjj parts ,moist blood cells3 ,average total weight #def4fi ,water #cdb4eb ,solid matter #ig4ej ,plasma3 ,total weight #edc4cj parts ,water #die4gb parts ,solid matter #cj4gb parts ,blood when drawn and allowed to stand soon coagulates4 ,in the blood of birds this process is very rapid1 the blood coagulating1 in most instances1 in about one-half minute4 ,blood coagulates only in the presence of calcium salts4 ,during life1 the liquor sanguinis is termed plasma2 but after it has been shed from the body and coagulation has taken place1 the liquid residue is called serum4 ,serum is plasma with its modifications as the result of coagulation1 and as this latter process is brought about by the production of fibrin1 we may say that serum is plasma minus fibrin-forming elements4 ,the proteids of the serum are serum globulin1 serum albumin1 and a ferment produced as the result of coagulation4 ,as fibrinogen is used up in the process of coagulation1 it is not found in the serum1 but there is in the serum a proteid known as fibrino-globulin4 ,this is produced from fibrinogen during the process of fibrin formation4 ,the following tabulation gives a clear idea of the difference between the proteids of plasma and of those of serum3 ,proteids of ,plasma ,fibrinogen ,serum globulin ,serum albumin ,proteids of ,serum ,serum globulin ,serum albumin ,fibrin ferment 7nucleoproteid7 ,fibrino-globulin ,fibrinogen is the precursor of fibrin4 ,the fibrin of the blood clot of the bird is soft and very lacerable4 ,the serum is usually yellow4 ,,the ,,fate ,,of ,,the ,,erythrocyte ,,of ,,the ,,fowl ,the power of vascular endothelium to ingest red blood corpuscles has been studied by ,keys4 ,when bacteria or other minute foreign bodies are injected into the blood stream of pigeons1 they are rapidly withdrawn from the circulation into the tissues of the liver and of the spleen4 ,the foreign bodies are noted to be contained within cells of a distinct type1 which is found in both liver and spleen4 ,this type of cell contains1 in addition to the foreign substances injected1 much yellow pigment1 and when tested for iron by ,pearl's method gives a positive ,prussian-blue reaction4 ,in such specimens there is a display of contrast to other tissues4 ,there is an extensive content of cells possessing the distinct tone of ,prussian-blue iron reaction4 ,these cells are distributed rather evenly throughout both the spleen and the liver1 but more numerously in the liver4 ,in the liver1 under low-power magnification1 these cells appear as blue patches1 sharply differentiated from the red-stained parenchyma4 ,these cells are larger in their greater diameter than the liver cells4 ,they vary much in size and form4 ,they bear a constant relationship to the venous capillaries1 and often appear to occupy the lumen of the vessels4 ,under higher magnification it is noted1 however1 that each cell is an integral part of the endothelial intima lining of the capillaries4 ,they are therefore fixed tissue cells1 engaged by one of its surfaces upon the reticulum of the vessel wall1 with a free surface bulging a greater or less degree into the lumen of the vessel4 ,the attached surface of the cell follows exactly the line of the vessel wall4 ,these cells are similar to those described for mammals by ,kupffer and are called ,kupffer cells or stellate cells4 ,in the fowl ,keys proposes the name hemophages4 ,the nucleus of the hemophage stains a deep garnet with the carmine used in the above-given technic1 and contains two or three very distinct and intensely stained nucleoli4 ,in the hemophages1 which are more nearly flat1 the nucleus appears like those of the typical endothelial cells2 whereas in the protruding hemophages of greater bulk1 the nucleus is more vesicular and is irregularly pyramidal in form4 ,rarely two nuclei are found in one cell4 ,within this cell may be seen vacuoles of the cytoplasm which contain red blood corpuscles4 ,these blood corpuscles have been phagocyted from the circulating blood stream4 ,approximately one-third of the intimal cells are hemophages4 ,each hemophage displays evidence that it contains1 or has recently contained1 one or more red blood cells4 ,the cell body of the hemophage has no fixed morphology1 but changes from time to time according to its phase of phagocytic activity4 ,in a stage which the hemophage has recently ingested a red blood cell1 the cell body bulges out into the lumen of the vessel and the nucleus is crowded to one side4 ,at this time the red blood cell appears as those in the blood stream and possesses the characteristic staining reactions4 ,the nucleus of the red blood cell stains deep reddish brown and the cytoplasm an even yellow bronze4 ,in the next stage the cytoplasm of the hemophage gives a diffuse ,prussian-blue reaction4 ,then in hemophages which represent later stages there are various stages of disintegration and digestion of the red blood cell4 ,the first changes of the phagocyted red blood cell is hemolysis1 the hemoglobin escaping into vacuoles of the cytoplasm of the phagocytic cell1 leaving the nucleus-containing stroma distinctly outlined4 ,the stroma may retain the original ovoid form or may become spherical2 the nucleus in such instances remains ovoid4 ,gradually1 both the stroma and nucleus lose their staining reaction until finally the vacuoles contract about a small indistinct remnant of the nucleus1 which in its turn ultimately disappears4 ,during this latter process the size of the hemophage gradually decreases4 ,the hemoglobin1 which has escaped into the cytoplasm of the hemophage1 is seen to undergo a series of changes4 ,at first the greater part of the pigment does not give the iron reaction but retains its yellow-bronze tone with erythrosin and occupies vacuoles of various sizes4 ,later the contents of the vacuoles give the iron reaction and with increasing intensity4 ,later there is a gradual decrease in the staining reaction indicating that the iron gradually disappears from the cells which extracted it from the red blood cells it digests4 ,as a summary we find1 that these cells take care of the worn out red blood cells4 ,they devour them2 hemolyze them1 destroying the stroma and nucleus2 split the hemoglobin and free the iron2 and then finally return to their normal form4 ,the spleen contains the same type cells1 but they are fewer in number4 ,for the most part they are confined to the pulp cords and have no such evident relation to the vessel wall1 or lumen1 as in the liver4 ,the function of the cells of the spleen are essentially the same as those in the liver4 ,iron freed from the worn out red blood cells is not retained by the cells freeing it1 nor is it found in the bile4 ,it does not occur elsewhere in the tissues of the liver and spleen4 ,it is possibly discharged into the blood stream1 and transported to the hemapoietic tissues4 ,cells which hemolyze red blood cells and liberate the iron are to be seriously thought of in connection with bile formation since bilirubin is approximately1 if not identical with1 iron-free hematoidon4 ,,neurology ,the ,nervous ,system4--,the nervous system is an apparatus by means of which animals appreciate and become influenced by impressions from the outer world4 ,animals react on these impressions1 and thus are enabled to adapt themselves to their environment4 ,this system is the organic substratum of life1 sensation1 and motion4 ,broadly stated1 the nervous system connects the various parts of the body with each other1 and to cordinate the parts into a harmonious whole in order to carry on the bodily functions methodically and to control the physiological division of labor throughout the organism4 ,the nervous system consists of two parts4 ,the first is the cerebro-spinal system1 which comprises the central nervous axis1 including the brain and the spinal cord1 and the peripheral nerves1 including the cranial and the spinal nerves4 ,the second is the sympathetic nervous system4 ,the two parts of the system are closely linked together1 and both terminate in peripheral nerve endings1 including those of special sense1 of sensation1 and of motion4 ,the cerebro-spinal nerves especially preside over the special senses1 motion and sensation2 and the sympathetic over the digestive1 the pulmonary1 and the vascular apparatus4 ,from a structural standpoint1 the nerve system consists of cell elements peculiarly differentiated from all other tissue cells in that their protoplasm is extended in the form of processes1 often to great distances from the nuclear region4 ,the cell elements are held in place by supporting tissue and receive an abundant blood supply2 they are partly of ectodermal and partly of mesodermal origin4 ,the cell element of the nerve system1 called a neurone1 is the developmental1 structural1 and functional unit of the nervous system4 ,it is a single cell presenting unusual structural modifications4 ,it comprises not only the nerve cell body with its numerous protoplasmic processes1 or dendrites1 but also the axone1 which may vary in length from a fraction of a millimeter to fully half the bird's length4 ,the bulk of the axone is many times the bulk of the cell body4 ,certain non-medullated axones are surrounded by a delicate1 homogeneous1 nucleated sheath1 called the neurilemma1 or sheath of ,schwann4 ,,the ,,cranial ,,nerves ,the cranial nerves have their origin in the brain and leave the cranial cavity in pairs4 ,they are numbered numerically from before backward1 there being twelve pairs in all4 ,the following is a tabulation according to their number1 name1 and function3 ,no4 ,name ,functional ,nature ,i4 ,olfactory ,smell-sense ,,ii4 ,optic ,visual-sense ,,iii4 ,oculomotor ,motor to muscles of eyeball and orbit ,,iv4 ,pathetici ,motor to superior oblique muscle of eyeball ,v4 ,trifacial ,mixed3 ,sensor to face and tongue4 ,motor to face ,,vi4 ,abducentes ,motor to ,external rectus of eyeball ,,vii4 ,facial ,motor to muscles of head and face ,,viii4 ,auditory ,hearing-sense ,,ix4 ,glosso-pharyngeal ,mixed3 ,tongue1 pharynx and muscles of throat ,x4 ,vagus ,mixed3 ,sensori-motor to respiratory tract and part of alimentary tract ,,xi4 ,spinal accessory ,motor to muscles of pharynx1 neck and heart ,,xii4 ,hypoglossal ,motor to muscles of the tongue ,olfactorius4--,nervus olfactorius 7,fig4 #ge1 ,c1 #af74 ,this is the nerve of smell1 one of the nerves of special sense4 ,the organ of smell consists of five layers as follows3 ,first1 a layer of olfactory fibers extending in different directions and consisting of a dense plexiform arrangement of the axones of the olfactory cells4 ,from this layer the fibers pass into the layer of olfactory glomeruli where their terminal ramifications mingle with the dendritic terminals of cells lying in the more dorsal layers1 to form distinctly outlined spheroidal or oval nerve fiber nests1 the olfactory glomeruli4 ,second1 a fine granular layer of basic substance containing round cellular structures1 the stratum granulosum4 ,third1 broader granular1 or molecular layer1 having on its inner surface a row of large pyramidal cells which are both small and large and which send their dendrites into the olfactory glomeruli4 ,their points are directed outward4 ,fourth1 a layer of round cells tightly pressed together and measuring about #e microns in diameter4 ,between these cells are very fine nerve fibers4 ,illustration3 ,,fig4 #ge4--,the brain of a hen4 ,photograph4 ,a4 ,upper surface of the brain4 #a1 ,medulla oblongata4 #b1 ,calamus scriptorius4 #c1 ,cerebellum4 #d1 ,optic lobes4 #e1 ,transverse fissure4 #f1 ,longitudinal fissure4 #g1 ,upper surface of the left cerebral lobe4 #h1 ,upper surface of the right cerebral lobe4 #i1 ,lateral pillar of the cerebellum4 ,b4 ,the posterior surface of the eyeball4 #aj1 ,the sectioned surface of the optic nerve4 ,c4 ,the inferior surface of the brain4 #aa1 ,corneo-scleral juncture4 #ab1 ,the cornea4 #ac1 ,the sclera4 #ad1 ,the optic nerve4 #ae1 ,the optic chiasm4 #af1 ,the olfactory lobes4 #ag1 ,the medulla oblongata4 #ah1 ,tuber cinererum et infundibulum4 ,fifth1 a layer of epithelial cells4 ,the peripheral fibers and the nerve cell layers near the hemispheres disappear so that the basic substance of the trabecula with the hemispheres form the entire lobe mass4 ,on the lower surface of the hemispheres there is a long bundle of nerve fibers which enter into the substance of the olfactory lobes and there disappears4 ,these fibers are medullated4 ,non-medullated fibers enter into the makeup of the olfactory trunk4 ,the original center of the olfactory nerve is not in the hemisphere1 but in the same location as the optic nerve4 ,this nerve trunk consists of very fine non-medullated fibers4 ,the nerves of smell are therefore not peripheralistic nerves4 ,the nerve fibers are distributed to the mucous surface of the turbinated bones4 ,toward the front they form an expanded prolongation4 ,the olfactory nerve1 as it emerges from the cone-like anterior tip of the cerebrum1 is of considerable thickness and extends along with the median dorsal artery of that region above and to the inside of the orbit1 under the thin bony structure4 ,before its termination into the posterior turbinated bones1 it is crossed by the superior maxillary division of the fifth pair of cranial nerves4 ,it extends as far as the pituitary membrane of the turbinate bones upon which its filaments are distributed radially4 ,the ,opticus4--,the nervus opticus 7,fig4 #ge1 ,no4 ,c1 #ad7 the second cranial1 is the nerve of sight4 ,the optic lobe1 or tuberculum bigeminum lies at the base of the brain on each side of the optic tract4 ,from the optic lobes the two trunks pass forward along the under surface of the cerebri1 forming the optic chiasm at the hypophysis 7,fig4 #ge1 ,no4 ,c1 #ae71 at which point the nerve fibers originating from the right side pass to the left1 and vice vers4 ,from the chiasm the true optic nerves pass forward to the posterior surface of the eyeball4 ,they are composed of a bundle of very fine1 marrow-like nerves4 ,these fibers enter into the ganglionic cells of the retina4 ,by removal of the finely adherent neurilemma1 the optic nerve is seen to be composed of parallel1 longitudinal lamell1 the margins of which are mostly free on one side4 ,the ,motor ,oculi4--,the motor oculi 7,fig4 #fb1 ,no4 ,c1 #aj71 the third cranial nerve is a motor nerve4 ,it originates close to the base of the brain behind the position of the hippocampus of mammals on the inner side of the crus cerebri1 and also on the inner somatic column close below and somewhat aside from the aqueduct of ,sylvius4 ,the nerve leaves the brain cavity through a distinct foramen near the foramen opticum1 and supplies the following eye muscles3 first1 after entering the orbit1 it sends a branch upward to the inferior portion of the inferior rectus2 then1 it gives off the thick ramus ciliaris4 ,the trunk then extends under the optic nerve and passes forward to innervate the inferior rectus1 the internal rectus1 and the inferior oblique4 ,a ciliary ganglion forms on the trunk4 ,the ,patheticus4--7,fig4 #fb1 ,no4 ,c1 #aa7 is a small motor nerve1 originating close to the sulcus centralis1 in the circle of the center brain over the valve of ,vieussens1 between the posteriors of the optic lobes4 ,it extends in a dorsal direction between the cerebellum and the lobus opticus1 to the posterior of the latter of which it then forms a loop ventrally4 ,lying close to the optic foramen it passes through a fine opening into the eye cavity and supplies the superior oblique muscle of the eye4 ,during its course it passes dorsally over the optic nerve1 and then crosses dorsally over the ophthalmic division of the fifth pair of cranial nerves and the internal rectus muscle4 ,the ,trifacialis4--7,fig4 #fb1 ,no4 ,c1 #ab74 ,this1 the fifth cranial1 is a mixed nerve and is divided into two parts1 portio major and portio minor4 ,the portio major originates in the ganglion cells of the posterior part of the brain4 ,commencing near the medulla oblongata it passes through the posterior part of the brain1 then upward and outward2 and along its route it forms the ,gasserian ganglion1 which lies partly in the cranial cavity or in its wall4 ,the portio minor consists of the downward passing fibers containing the motoric elements which are distributed to the muscles of the jaw and of the eye4 ,the roots are found in the ganglion from the center and back brain1 close below the pathetic nerve origin1 where the pathetic passes between the lobus opticus and the pars peduncularis2 it then takes a lateral course between the two4 ,the fibers of the portio minor do not take part in the formation of the ,gasserian ganglion1 but are only partly surrounded by it4 ,there are three nerve trunks given off of the trifacialis3 the ophthalmic1 the superior maxillary1 and the inferior maxillary4 ,the ophthalmic division of the fifth nerve is the smallest of the three branches4 ,it emerges directly from the ,gasserian ganglion1 and passes through a narrow bony canal in the base of the brain1 below the pathetic and the abducens1 and through the foramen ophthalmicum4 ,it then enters the eye cavity above the optic nerve1 and on the wall of the cavity extends downward1 and with regard to the eyeball1 dorsally lying close to the rectus internus muscle and close to the surface of the eyeball4 ,it passes along the olfactory nerve1 extends under the superior oblique muscle1 and finally reaches the inner angle1 or canthus1 of the eye4 ,it here divides into the recurrent externa and the ethmoidalis4 ,the ethmoidalis branch is a straight continuation of the ophthalmic4 ,it extends along close to its fellow of the opposite side1 and1 over the vomer1 splits into two branches4 ,the smaller of these branches breaks through the bone cells of the jaw1 continues upon its ventral surface in a furrow extending forward1 and terminates in the gum region4 ,it supplies the gum and point of the beak4 ,the larger branch enters into the cell substance extending to the tip of the beak1 in its course sending out a number of fine filaments1 which spread out along the outer surface4 ,at this point these two branches may fuse4 ,the larger branch is endowed with the sense of touch4 ,the recurrent externa divides shortly after leaving the main trunk of the eye cavity passes over the lacrimal gland4 ,it gives two branches to this gland and one to the membrana nictitans1 and innervates the upper eyelid4 ,it then emerges from the eye cavity1 passing over the os lacrimale1 and gives one or more branches to the integument of this region1 including the comb4 ,this branch is large in birds with a large comb4 ,branches pass in front of the lacrimal bone through the outer nasal cavity and into its deeper structure4 ,shortly after the ophthalmic branch has entered into the eye cavity and before it crosses the optic nerve1 it gives a fine branch to the motor occuli4 ,the second and the third branches of the fifth cranial nerve are mixed4 ,they contain elements of both the portio major and the portio minor4 ,these two branches come from the lower part of the outer region of the ganglion1 and pass together through a cavity which is located between the os petrosum and al and basis sphenoid1 and then branch4 ,the ramus secundus1 or superior maxillary division1 of the trifacial1 is the second branch and passes into the orbit below the optic nerve and the eyeball4 ,it is called the recurrent infra-orbitale4 ,it gives an ascending branch to the gland of ,harder1 one to the conjunctiva1 one to the membrana nictitans1 and one to the eyelids4 ,it also gives a branch to the skin below the eye and to the angle of the mouth4 ,this latter branch is called the recurrent subcutaneous4 ,these two branches communicate with the recurrent nasal ciliaris of the first trigeminus branch4 ,the second branch passes below the nasal opening1 then passes on and forms the alveolar nerve on the side between the gums4 ,it sends several recurrent posterior branches to the elevations on the back part of the mouth4 ,it extends forward to the point of the beak4 ,the inferior maxillary division of the fifth is larger than the other two4 ,it is directed downward and outward then upward to the temporal region4 ,at the temporal region it divides into five parts4 ,it gives a branch to the temporalis muscle1 one to the pterygoid muscle1 and one to the mylo-hyoideus4 ,the main branch gives twigs to the parotid gland region and enters into the dental canal of the lower jaw4 ,numerous filaments break through the lower jaw bone1 and then spread out on the skin and rim of that bone4 ,the largest branch1 called the recurrent maxillaris externa1 comes out near the coronoid process4 ,the rest of the trunk extends to1 and comes out of1 several foramina at the anterior point of the jaw bone4 ,these filaments are contained in grooves or cavities of the lower jaw and terminate in touch buds4 ,the trifacialis fuses with the other cranial nerves and with the sympathetic nervous system4 ,some of these fusions are as follows3 ,the recurrent ophthalmica fuses with the orbito-nasalis ganglion4 ,indirect fusion of the recurrent maxillary division of this nerve takes place near the ,gasserian ganglion through the sympathetic nerves1 the temporo-lacrimalis1 the facial nerves1 the large cervical ganglion1 and indirectly with the glosso-pharyngeal and the vagus4 ,this fusion has been called the superior recurrent branch of the trigeminus1 or trifacialis4 ,there is a direct fusion of the superior recurrent maxillary division of the fifth just before entering the upper jaw4 ,this fusion is with the spheno-palatine ganglion and the sympathetic carotidis cephalica1 and also with the large cervical ganglion4 ,the ,abducens 7,fig4 #fb1 ,no4 ,c1 #ac74--,this nerve originates in the somatic and motoric column along with the other nerves of the eye muscles4 ,its nucleus lies in the circle of the pars commissuralis of the cerebellum4 ,the nerve then passes ventrally1 as does the motoris oculi and leaves the brain along the median line4 ,this is a comparatively large nerve and passes somewhat laterally and ventrally from the foramen opticum through a canal in the sphenoid4 ,it then enters the orbital cavity4 ,some muscular twigs are given off to the quadratus and to the pyramidalis muscle4 ,this nerve also innervates the external rectus muscle of the eye4 ,the abducens anastomoses with the ramus ciliaris and the ophthalmic nerve and gives fine nerve twigs to the ramus ciliaris externus of the ciliary ganglion4 ,the ,facialis and the ,acusticus4--,the facial nerve originates with the auditory 7,fig4 #fb1 ,no4 ,c1 #ad and #ae7 in a very vaguely known manner1 from the cerebellum4 ,it divides into three parts4 ,the first of these probably comes from the complex ganglion with the posterior roots of the auditory4 ,this part belongs to the somatic sensory group of nerves4 ,from this same group originates the auditory1 which spreads out into the cochlea and takes the impressions of sound4 ,this nerve is short and thick1 and1 at the point where it loses its medullary covering on entering the cochlea1 there is developed a ganglion4 ,this ganglion is similar to the spinal ganglia4 ,the second part is provided with one root which originates mesially and ventrally1 from the deeper ganglion cells4 ,some of the fibers from this root constitute the vestibular branches4 ,they accompany the auditory and supply the anterior part of the ear labyrinth and the semicircular canals4 ,the larger part of the fibers of this trunk make up the intermediate part of the facial4 ,the geniculate ganglion is formed at their fusion4 ,the sympathetic spheno-palatine nerve emerges from this ganglion1 coming out of the aqueduct of ,fallopius4 ,the third part1 called the portio dura1 is the main facialis4 ,it is located opposite the auditoria intermedia4 ,its roots may be traced to the complex ganglion1 from which they take a direction ventrally from the median portion4 ,the facialis1 after emerging from the aqueduct of ,fallopius1 takes a curved course and partly fuses with the sympathetic temporo-lacrimalis on the upper posterior wall of the ear drum4 ,it is here accompanied by the carotid and the cephalic arteries4 ,it leaves the ear drum through an opening in the quadrate bone1 giving off a large branch to the digastricus muscle and a small one to the stapedius of the columella auris4 ,the facialis trunk is quite large4 ,it then passes downward along the quadrate bone1 where it receives a large branch from the glosso-pharyngeus4 ,this nerve also gives branches to the mylo-hyoideus and the stylo-hyoideus muscle1 crosses laterally the glosso-pharyngeus1 and finally fuses with branches of the subcutaneous and with the first1 the second1 the third1 and the fourth cervical nerves4 ,after this fusion the nerves innervate the skin of the anterior of the neck and the constrictor colli muscle4 ,the facialis anastomoses as follows3 with a fine branch of the sympathetic temporo-lacrimalis1 indirectly with the ramus trigeminus1 with the large cervical nerve ganglion and with the spheno-palatine ganglion and nerve4 ,the ,vagus ,group4--,the ninth1 the tenth1 and the eleventh cranial nerves are by some anatomists called the vagus group1 first so called by ,willis4 ,they are made up of both sensory and motor nerves4 ,the ,glosso-pharyngeus4--,the roots of the glosso-pharyngeus 7,fig4 #fb1 ,no4 ,c1 #af2 ,fig4 #gf1 ,no4 #ac7 emerge1 along with those of the vagus1 from the medulla oblongata1 and enter1 as a short trunk1 the foramen jugulare et caroticum4 ,between these two nerves there is usually found a thin portion of bone4 ,the trunk of the glosso-pharyngeus forms a ganglion in the foramen jugulare et caroticum where it receives connecting branches from the near-by ganglion radicis and vagus nerve4 ,the glosso-pharyngeus passes out of the foramen jugulare et caroticum above the large superior sympathetic nerve ganglion1 with which it communicates4 ,the glosso-pharyngeus passes diagonally over the ramus temporo-lacrimalis of the sympathetic system1 and then receives a very strong branch from the vagus 7,fig4 #gf1 ,no4 #ab74 ,it sends a short branch to the recurrent lacrimalis of the sympathetic system4 ,at this point there is formed a reddish-yellow ganglion1 the petrosal ganglion1 which is similar to the petrosal ganglion of mammals4 ,frequently it is found close below the large superior cervical nerve ganglion4 ,the petrosal ganglion is frequently connected by special fibers with the cervical nerve ganglion1 the large superior cervical nerve ganglion and the ganglion radicis vagi4 ,the glosso-pharyngeus is divided into the following branches4 ,first1 the recurrent pharyngeus which gives branches to the upper part of the throat and which is tortuous in its course4 ,it receives a branch from the superior cervical nerve ganglion and gives off branches to the salivary glands and papill of the posterior tongue region4 ,second1 the recurrent lingualis1 which passes with the lingual artery over the hyoid bone to the base of the tongue and to the papill4 ,another branch passes below the tongue bone and supplies the tongue and the pharynx4 ,the glosso-pharyngeal is a mixed nerve4 ,illustration3 ,,fig4 #gf4--,photograph of spinal cord of a hen4 #a1 ,cerebrum4 #b1 ,the olfactory nerve terminating at #c1 the turbinated bones4 #d1 ,the superior maxillary division of the fifth nerve dividing4 #e1 ,the eye with the upper part laid open4 #f1 ,the cervical segment4 #g1 ,the lumbo-sacral segment4 #h1 ,the lungs4 #i1 ,the kidneys lying above the peritoneum4 #aj1 ,the terminal filament of the spinal cord4 #aa1 ,the hypoglossal nerve4 #ab1 ,the vagus nerve4 #ac1 ,the glosso-pharyngeal nerve4 #ad1 ,the branch from the vagus4 ,the ,vagus4--,the vagus1 or pneumogastricus 7,fig4 #ah1 ,no4 #e2 ,fig4 #fb1 ,no4 ,c1 #ag2 ,fig4 #gf1 ,no4 #ab71 a mixed nerve1 forms a ganglion in the foramen through which it passes4 ,the foramen lies between the os petrosum and os occipitale1 close to the foramen jugulare1 above and to the inside of it4 ,the ganglionic root of the vagus communicates with the superior cervical nerve ganglion4 ,the vagus1 after coming out of the foramen1 takes up branches of the spinal accessory1 passes to the superior nerve ganglion1 crosses the carotid artery1 and then1 accompanied by the internal jugular1 it connects by a branch with the hypoglossal4 ,it then communicates with the petrosal ganglion1 and receives a long branch from the superior cervical ganglion4 ,it then extends along the neck with the jugular vein and often fuses with the sympathetic ganglionic plexuses4 ,as it passes1 it is interwoven with the glosso-pharyngeus1 but each nerve element retains its own individuality4 ,extending down the neck1 on entering the thoracic cavity1 it lies between the plexus brachialis and the carotid artery4 ,then it passes below the subclavian artery1 and between the bronchial tubes1 the aorta pulmonalis1 and the subclavian vein4 ,then ventrally it rests upon the glands1 and the right and the left vagi fuse or unite4 ,from here they radiate down to the stomach in fan-shape1 and1 continuing1 they fuse with the sympathetic system4 ,the other branches of the vagus are3 ,the first branch is the recurrent laryngeus1 which supplies the lower end of the bronchial tubes1 and the esophagus1 then enters above the bronchus near the origin of the subclavian artery as the recurrent cardiacus4 ,the second are the recurrent pulmonale which pass into the lungs1 each fusing with its fellow from the opposite side1 and giving off branches inferior to the vena cava including a branch to the heart4 ,the third are the recurrent hepatici which pass through the diaphragm and are distributed to the liver4 ,the ,accessorius ,spinalis4--,this is a very small motor nerve 7,fig4 #fb1 ,no4 ,c1 #ah74 ,it comes out between the dorsal and the ventral root of the third cervical nerve4 ,it lies close to the neck and extends anteriorly1 receiving roots from the first and the second cervical nerve4 ,it passes through the occipital foramen into the brain cavity and then enters the ganglion radicis vagi4 ,it passes out of the cranial cavity through the foramen jugulare4 ,it then partly fuses with the vagus and partly1 as a fine branch1 with the subcutaneous colli4 ,the ,hypoglossus4--,the hypoglossus is a motor nerve 7,fig4 #fb1 ,no4 ,c1 #ai74 ,it originates anterior to the eleventh pair of cranial nerves1 and from the same ganglion as the abducens and the motor oculi4 ,it leaves the medulla oblongata from its ventral surface1 and passes with a posterior and an anterior branch out of the cranial cavity through two separate foramina in the os occipitale laterale4 ,the posterior branch1 much smaller than the anterior1 passes between the cranial bones and the cervical sympathetic nerve2 it then passes at right angles through the rectus capitis anticus1 and1 while closely following the carotid artery1 it fuses with the anterior branch4 ,the larger1 anterior branch1 much stronger than the posterior1 sends a short strong branch to the complexus muscle4 ,the rest of this branch1 which probably has sympathetic elements1 is disposed as is a spinal nerve4 ,it crosses the sympathetic nerve1 and at this point forms a typical cervical sympathetic ganglion4 ,it also forms a short loop with the recurrent ventralis of the first cervical plexus4 ,from this loop1 after it has given off several branches to the muscles of the neck1 it gives off one or two strong branches1 which fuse with each other and with the posterior thin branch1 thus forming the trunk of the hypoglossus4 ,it receives many elements from the first cervical nerves4 ,the hypoglossus sometimes communicates with the vagus1 crosses over the latter1 and divides itself into two main branches1 as follows3 ,first1 the recurrent laryngo-lingualis1 which passes between the cornua of the os hyoideum and the larynx to the anterior part1 and furnishes the principal tongue muscles4 ,it extends along the inferior surface of the tongue and fuses with the one of the other side and extends to the free tip of the tongue4 ,this nerve probably receives sensory elements from the second root and from the confluent of the first cervical nerve4 ,this form of anastomosis is well marked in birds with thick tongues1 as ducks4 ,second1 the recurrent laryngeus furnishes the muscles of the superior larynx and of the tongue skeleton4 ,it extends downward and also furnishes the muscles of the trachea4 ,it follows the course of the jugular vein and at the entrance of the chest supplies the furcula4 ,the nerve passes into the thorax1 downward along the side of the bronchial tubes1 and supplies innervation to all the muscles of the inferior larynx4 ,,the ,,spinal ,,cord ,structure of the ,cord4--,the spinal cord is called the myelon or medulla spinalis4 ,it is a comparatively large1 white1 irregularly cylindrical cord1 flattened from above downward4 ,it extends from the foramen magnum at the base of the medulla to the caudal portion of the spinal canal where it terminates in a fine filament4 ,in order to allow considerable motion of the spinal column without danger of injury to the spinal cord1 the cord is loosely suspended in the canal4 ,the meninges1 or coverings1 are continued from the brain4 ,in addition to these there are to be found arteries1 veins1 and nerves entering and others making their exit from the canal and from the cord4 ,at the cervico-dorsal juncture1 where the brachial plexus is given off1 the cord is enlarged4 ,there is another enlargement at the point where the lumbo-sacral plexus is given off4 ,at this point1 superiorly1 there is a longitudinal cavity called the sinus rhomboidalis4 ,this sinus contains a gelatinous substance4 ,there is a pair of nerves given off at each intervertebral foramen4 ,thus there are as many pairs of spinal nerves as there are vertebral segments4 ,the inferior root is the motor root and carries the impulses from the cord to the periphery4 ,the superior root is the sensory branch and carries the impulses from the periphery to the cord1 and thence the impulse is carried to the centers in the brain4 ,the sensory and the motor roots are of about equal size4 ,the inferior have more numerous filaments4 ,the ganglion on the superior or sensory root is relatively large4 ,in the sacral region the sensory and the motor branches pass through their own bony canal4 ,white rami communicantes are given off at each intervertebral foramen to the sympathetic system and gray rami are received from the sympathetic ganglia4 ,thus there is established a direct communication between the sympathetic and the spinal system4 ,there is a ganglion on the superior root just outside the spinal cord4 ,the ganglionic portion1 or gray matter1 is arranged in the center of the cord in two comma-shaped parts forming an ,x4 ,the white matter1 or the material forming the fibers1 is arranged around the central ganglionic portion4 ,the spinal cord may be divided into two lateral symmetrical halves4 ,there are two longitudinal fissures1 one on the upper and the other on the lower half4 ,the upper called the superior median fissure is narrow but deep4 ,the one on the inferior side1 called the inferior median1 is usually more pronounced4 ,the superior parts of the gray matter are called the superior cornua1 or horns2 the inferior parts the inferior cornua1 or horns4 ,the center of the cord is pierced by a central canal which communicates with the fourth ventricle at the calamus scriptorius4 ,,structure ,,of ,,the ,,nerve ,,trunks ,,and ,,ganglia ,the protoplasmic processes called dendrites have a similar structure to the cell body4 ,the dendrites branch dichotomously1 become rapidly smaller1 and usually end at no great distance from the cell body4 ,the axone or axis cylinder process1 differs from the cell body and from the dendrites4 ,it does not contain chromophilic granules4 ,it consists entirely of neurofibrils and perifibrillar substance4 ,it emerges from the cell at an enlargement known as the axone hill4 ,this hill is free from chromophilic bodies4 ,nerves are divided into two kinds1 medullated and non-medullated4 ,medullated nerves are divided into two kinds3 medullated nerves with a neurolemma1 and medullated nerves without a neurolemma4 ,medullated nerves with a neurolemma consists of an axone1 a medullary sheath1 and a neurolemma4 ,a delicate membrane called an axolemma1 or periaxial sheath envelops the axone4 ,the medullary sheath called myelin1 is semifluid1 somewhat resembling fat4 ,the outer covering is the neurolemma1 or sheath of ,schwann4 ,it is a delicate1 structureless membrane which incloses the myelin4 ,there is under this sheath an occasional oval nucleus4 ,at intervals there are constrictions1 or nodes1 called the constrictions of ,ranvier4 ,the part between the nodes is called the internode4 ,the medullated axones without a neurolemma are the medullated nerve fibers of the central nervous system4 ,the non-medullated axones1 or non-medullated nerve fibers1 are divided into non-medullated axones with and those without1 a neurolemma4 ,the non-medullated axone without a neurolemma is merely a naked axone4 ,they are confined to the gray matter and to the beginnings and endings of sheath axones1 all the latter being uncovered for a short distance after leaving the nerve cell body and also just before reaching their terminations4 ,the long axones serve to make connections with the peripheral1 or distant1 nerve cell1 muscle cell1 or gland cell2 while the shorter axones of certain neurones divide into terminal branches in the immediate vicinity of its cell body1 presumably to come into relation with other nerve cells in the same or adjacent groups4 ,illustration3 ,,fig4 #gg4--;,histological structure of tissues4 #a4 ,non-striated or involuntary muscle cell4 a4 #a1 ,nucleus2 #b1 ,protoplasm4 b4 ,transverse section showing nuclei in the center of the cells that are cut through the nuclear zone4 c4 ,a cross-section of the connective tissue which binds together the muscle cells4 d4 ,a section showing the so-called intercellular bridges4 #b4 ,a cross-section of the rectus abdominalis4 #a1 ,the endomysium which binds the cells into primary fasciculi or bundles4 #b1 ,the perimysium which surround the bundles of fasciculi4 #c1 ,the epimysium which surrounds the muscle4 ,these binding structures are white fibrous connective tissue4 #c4 ,a longitudinal section at the juncture of a muscle and tendon4 a1 ,the juncture between the muscle and tendon4 ,note the many nuclei in both muscle and tendon4 ,this is voluntary or striated muscle which make up the dermal1 dermo-osseous and skeletal muscles4 #d4 ,a longitudinal section of heart muscle4 a1 ,connective-tissue cell4 b1 ,nucleus of a muscle cell4 c1 ,cement line between the muscle discs4 d1 ,the cell or segment4 #e4 ,a bipolar ganglionic nerve cell4 a1 ,the nucleus4 b1 ,the nucleolus4 c1 ,the fibrillar structure4 d1 ,the medullary sheath4 #f4 ,a diagram showing the scheme of the peripheral nerve trunk4 a1 ,the neuraxis of the peripheral sensory neurone4 b1 ,the spinal ganglion of the superior or sensory root4 c1 ,the dendrite or peripheral nerve fiber of the sensory nerve4 d1 ,the nerve trunk4 f1 ,the sympathetic nerve ganglion connected with the spinal cord through the white and the gray ramus communicans4 e1 ,the neuraxis of the sympathetic neurone4 g1 ,neuraxis or trunk of the motor neurone or nerve cell4 h1 ,the anterior horn of the gray matter of the spinal cord4 #g4 ,a diagram of a peripheral sensory neurone4 a1 ,the neuraxis which ends in the spinal cord or brain4 b1 ,the ,t-shaped division of ,ranvier4 c1 ,the dendrite or sensory nerve fiber in the nerve trunk4 d1 ,the nucleus and nucleolus of the cell e41 f4 the axis cylinder process of the cell4 g1 ,the telodendrions or terminal branches of the dendrite or axis cylinder4 #h4 ,a schematic diagram of the sensory motor reflex4 a1 ,the telodendria4 b1 ,the dendrite4 c1 ,nerve cell of the motor neurone4 d1 ,the motor neurone4 f1 ,the muscle fiber4 g1 ,the neuraxis of both sensory and motor neurones1 the upper being the sensory4 h1 ,the nerve cell in the sensory ganglion4 i1 ,the sensory neurone or axis cylinder 7nerve fiber74 j1 ,the skin with peripheral telodendrion of sensory neurone4 ,neurones are devoted to the maintenance of functions4 ,reproductive neurones are so arranged as to receive afferent nerve impulses from other tissues2 emissive neurones give off efferent nerve impulses4 ,the former are sensory neurones2 the latter are motor neurones if connected with muscles1 and excito-glandular if connected with gland cells4 ,the basis1 then1 of the nerve system is a series of neurones1 with projecting and association processes1 cordinated for the purpose of performing specific actions manifested either by motion1 by trophic changes1 or by the apperception of stimuli of a chemic1 mechanic 7tactile and auditory71 thermal1 or photic nature4 ,the whole of the nerve structure is composed of the nerve tissue and supporting connective tissue4 ,the neurones constitute the nerve tissue1 while the supportive tissue is composed of neuroglia and of white fibrous tissue derived either from the investing membrane or from the sheaths of its numerous vascular channels4 ,the neurones1 or nerve cells1 exhibit marked variations as to external characters1 dimensions1 and form4 ,the neurone presents a swollen cell mass and a nucleus2 it is known as the ganglion cell4 ,from this cell body are given off a number of processes of two distinct kinds3 first1 protoplasmic processes1 which are commonly branched1 called dendrites2 second1 a single1 thinner1 and paler process2 the axis cylinder process4 ,the bodies of cells vary in size from #d to #ajj microns or more in diameter4 ,the largest cells occur in the inferior horn of the spinal cord1 in the spinal ganglia1 in the large pyramidal cell layer of the cerebral cortex1 in the ,purkinjean cell layer of the cerebellum1 and in ,clark's column of the spinal cord4 ,very small cells occur in the olfactory bulbs1 in the granular layer of the cerebral and cerebellar cortex1 and in the gliosum cornuale of the cord4 ,nerve cells are classified according to the number of processes arising from the cell body1 and neurones are referred to as unipolar1 bipolar1 and multipolar4 ,unipolar cells are met with frequently in early stages of embryonic development1 but are rare in adults1 occurring only in the retina1 in the olfactory bulb1 and within the baskets of the ,purkinjean cells of the cerebellum4 ,the cells of the cerebro-spinal ganglia1 except the cochlear and vestibular1 are apparently unipolar1 but they are developmentally and functionally of bipolar nature4 ,bipolar cells are found almost exclusively in the peripheral sensory system1 as in the olfactory membrane1 in the retina1 in the cochlear and vestibular ganglia1 and in the cerebro-spinal ganglia of the embryo4 ,multipolar cells are the most numerous and form the principal elements of nerve centers throughout the system4 ,they are termed multipolar because of the greater or lesser number of dendrites given off in addition to the single axone4 ,the body of the nerve cell consists of a mass of protoplasm surrounding a nucleus4 ,the cytoplasm of the nerve cell consists of two distinct substances3 first1 neurofibrils2 second1 perifibrillar substance4 ,in most nerve cells there is a third substance called chromophilic bodies4 ,the neurofibrils1 extremely delicate1 are continuous throughout the cell body and all of its processes4 ,within the body of the cell they cross and interlace and probably anastomose4 ,the perifibrillar substance is a fluid or a semifluid substance which both in the cell body and in the processes surrounds and separates the neurofibrils4 ,the chromophilic bodies are granules or groups of granules which occur in the cytoplasm of all the larger and of many of the smaller nerve cells4 ,,the ,,spinal ,,nerves ,the first pair of spinal nerves come out between the atlas and the occipital bone4 ,each nerve divides into three branches4 ,the first is the anterior branch which innervates the dorsalis1 the biventer cervicis1 the cervicales1 and the caput posticus muscles4 ,the second is the recurrent ventralis which passes mesially and downward from the recurrent communicans4 ,it innervates the rectus capitis anticus muscle and joins a branch of the hypoglossal nerve4 ,there is given off a white ramus communicans to the sympathetic nerve4 ,the second spinal nerve emerges from the opening between the first and the second cervical vertebr and is similarly disposed as the first cervical4 ,it gives off a branch called the recurrent ventralis which fuses with branches of the first cervical and the hypoglossal nerve4 ,this nerve innervates the complexus muscle4 ,the succeeding cervical nerves emerge in a similar manner down the neck and are distributed to the muscles and other structures of the cervical region4 ,the second1 the third1 and the fourth cervical nerve gives off branches which form anastomosing loops with the facial nerve4 ,according to ,gadow the last cervical nerve passes between the last cervical and the first dorsal segment4 ,there are thus fifteen pair of cervical nerves4 ,the first pair of dorsal nerves pass out between the first two dorsal vertebr4 ,the first few dorsal nerve branches innervate only the trunk muscles4 ,other branches supply the skin and the other adjacent integument4 ,the ventral branches of the cervical nerves often communicate with the ventral branches of the first dorsal nerves4 ,these branches are larger than the superior branches and aid in the formation of the brachial plexus4 ,smaller inferior branches are distributed to the scalenus and other muscles1 and extend as far posterior as the intestines4 ,the dorsal branches of the spinal nerves in the lumbo-sacral region are very small1 on account of the lack of extensive development of the muscles of this region4 ,the elements entering into these nerve trunks are largely vasomotor nerves4 ,in addition to the upper twigs supplying the skin and the other integument of the region1 other branches descend into the abdominal cavity4 ,the caudal spinal nerves are not well developed and disappear in the region of the caudal vertebr4 ,the dorsal branches innervate the levator muscles1 and the ventral branches the depressor muscles4 ,there is thus given off1 throughout the vertebral column1 a pair of nerves between each two vertebral segments1 making as many pairs of nerves for the region as there are vertebral segments of that region4 ,the ,brachial ,plexus4--,the brachial plexus 7,fig4 #gc1 ,no4 #ai7 arises principally from the roots of the last three cervical and the first dorsal spinal nerves4 ,these branches anastomose beneath the deep face of the scapulo-humeral articulation4 ,the brachial plexus divides into two distinct parts4 ,the first 7,fig4 #gc1 ,no4 #bj7 the dorsal called the superior thoracic is distributed to the serratus and the rhomboideus muscle4 ,the second is the inferior thoracic 7,fig4 #gc1 ,no4 #ba71 which consists of the main plexus1 and which gives off muscular branches especially to the sterno-coracoideus and to the main portion passing on as the nerve trunk to the structures of the wing4 ,from the superior thoracic plexus there are several secondary plexuses formed4 ,the dorsalis or serratus plexus4 ,this plexus is located adjacent to the anterior part of the main plexus and is formed of from two to four spinal nerve branches4 ,the rhomboideus is supplied by branches which may be traced to the first root of this plexus4 ,this nerve is called the rhomboideus superficialis4 ,another nerve is given off from the middle part of the dorsal side of the plexus and is called the rhomboideus profundus4 ,a third1 the superficialis serratus1 is the largest of the branches4 ,it breaks up into terminal branches1 one going to each serration1 or digitation1 of the serratus muscle4 ,branches from the anterior portion of this plexus are distributed to the patagii muscles4 ,the superior brachial plexus gives off the following nerves3 ,the subcoraco-scapularis1 which is purely a motor nerve1 springs from the anterior roots of the plexus4 ,it gives off a branch to the following three muscles3 subcoracoideus1 subcoracoido-scapularis1 and scapulo-humeralis4 ,the scapulo-humeralis is distributed to the scapular humeral region4 ,the latissimus dorsi is located on the peripheral border of the scapulo-humeralis or supraspinatus4 ,it originates from the second1 and the fourth nerve roots of the plexus4 ,it is located on the dorsal side of the plexus4 ,it divides into two main branches1 one going to the latissimus dorsi and the other to the scapulo-humeralis muscle4 ,from the side are given off branches which supply the patagii muscle and enter into the formation of the dorso-cutaneous plexus4 ,the axillaris springs from the second and the third root of the brachial plexus1 extends in a lateral direction1 passing the ventral and distal rim of the insertional part of the posterior scapulo-humeralis or teres et infraspinatus and enters near the capsular ligament of the shoulder-joint4 ,it gives off to this joint a small branch1 called the recurrent articularis1 which passes outward between the triceps brachialis and the humerus4 ,it lies on the inner side of the major deltoid1 and patagii muscles1 and also the skin of the lateral shoulder and the upper arm region4 ,the recurrent axillaris communicates with the main branch of the radial nerve4 ,the cutaneus brachii superior is a small nerve which springs from the last brachial plexus root and passes between the skin and the triceps brachii muscle on the dorsal surface of the upper arm1 or brachial1 region4 ,it extends down over the elbow region1 where it gives off numerous branches to the skin of these regions1 to the meta-patagium and to the extensor muscles of the upper arm4 ,the brachialis longus superior is a large nerve trunk which springs from most of the other plexus roots4 ,it extends around to the dorsal side of the upper arm and supplies the skin1 the feathers1 and the muscles of the forearm and the hand4 ,branches from this nerve trunk supply the triceps brachii and other muscles of the region4 ,the main branch passes between the radius and the ulna1 and1 passing the elbow-joint1 gives off branches to that joint4 ,passing on1 it divides into two branches4 ,one of these extends superficially over the upper part of the condylus ulnaris and supplies the extensor digitorum communis and the extensor metacarpi ulnaris1 or flexor metacarpi radialis muscles1 and1 continuing superficially to the ulnar side1 is distributed to the skin of the region4 ,the second1 a deep branch1 extends on the ulnar side of the radius over the extensor indicis longus1 and innervates the latter muscle1 the extensor pollicis longus1 the extensor pollicis brevis1 the adductor pollicis1 the interosseous palmaris1 and the flexor digitorum4 ,the inferior brachial plexus gives off the following branches3 ,the supra-coracoideus1 a large nerve which springs from the first main root of the plexus1 and passes outward through the foramen coracoideum of the sternal ligament4 ,the sterno-coracoideus1 a small nerve which extends downward from the plexus4 ,the somewhat large posterior coraco-brachialis1 nerve which springs from one or two middle roots of the plexus and accompanies the pectoral nerve4 ,the anterior thoracic1 a large nerve which springs from two or three of the posterior roots of the plexus and extends to the shoulder cavity where it branches4 ,the anterior branch is distributed to the patagium and the front part of the pectoral muscles4 ,the posterior branch supplies muscles along the side of the thorax and extends into the abdominal muscles4 ,the anterior coraco-brachialis1 a small nerve which springs mostly from the inferior longus brachialis1 passes to the distal end of the tuberculum humeralis radii1 then passes backward between the front part of the humerus and the biceps1 where it supplies the anterior coraco-brachialis4 ,the cutaneous brachialis et inferior brachialis1 a small nerve which springs from the posterior roots of the plexus4 ,it is distributed to the skin of the region and branches are given off to the patagii and the ventral wing surface4 ,a few branches extend as far as the upper arm4 ,the brachialis longus inferior 7,fig4 #fh1 ,no4 #b71 a continuation of the main trunk of the inferior brachial nerve1 which comes out of all the plexus roots except the first4 ,it gives off some branches to the pectoral region and then enters the shoulder cavity4 ,it gives off the anterior coraco-brachialis1 passes down the humerus in an ,s-shape1 and divides into two branches1 the ulnar and the median4 ,the ulnar nerve 7,fig4 #fg1 ,no4 #c7 divides into numerous branches which are distributed to the ulnar side of the forearm and the hand4 ,the ulnar nerve passes below the skin of the ulnar outside rim of the forearm and gives branches to the carpi ulnaris1 finally supplying the flexor digitorum2 it then passes with the tendon of this muscle downward to the interosseous dorsalis1 the abductor indicis1 or flexor minimi brevis1 the flexor pollicis1 and the abductor pollicis1 or extensor proprius pollicis4 ,the median nerve 7,fig4 #fg1 ,no4 #b7 extends down the arm and gives branches to the biceps muscle1 and to the patagii region4 ,continuing1 the median nerve supplies the pronator muscle and the brachialis inferior1 or brachialis anticus1 and then divides into two branches4 ,the first and largest branch passes between the two pronator muscles giving branches to the pronator profundus1 or pronator longus1 and the flexor digitorum profundus muscle4 ,this nerve then passes anteriorly along the tendon to the base of the digit1 and1 on the dorsal side1 joins the other branch of the median nerve4 ,at this point there is often a plexus1 and at the point of fusion of the ulnar nerve on the ulnar side there may also be a small plexus4 ,these plexuses mainly supply the skin of these regions4 ,the second branch1 passes forward1 crosses the extensor carpi radialis and lies just below the pronator profundus1 or pronator longus1 giving branches to the skin4 ,it passes downward on the radial side of the ulnar and supplies the muscles of that part2 it then continues down the hand4 ,branches are given off to the extensor proprius pollicis1 the interosseous dorsalis1 the flexor digitorum1 and to the skin between the thumb and the forefinger4 ,the intercostal nerves 7,fig4 #gj1 ,no4 #ah7 are given off from the spinal cord of the dorsal region4 ,the superior branches are small and supply the superior dorsal region4 ,the inferior branches lie one behind each rib1 innervate the intercostal muscles1 and give a few twigs to the superficial thoracic muscles4 ,the ,lumbo-sacral1 or ,crural1 ,nerve ,plexus4--,the crural plexus 7,fig4 #gj1 ,no4 #ce and #cf7 is made up of trunks from the last two lumbar and first four sacral spinal nerves4 ,there are two portions of this plexus separated by a considerable distance4 ,the anterior portion 7,fig4 #gj1 ,no4 #ce7 consists of the lumbar nerves and a portion of the first sacral nerves4 ,the fusion takes place on the bony ridge that separates the lumbar from the sacral region4 ,the posterior portion 7,fig4 #gj1 ,no4 #cf7 consists of a part of the first sacral and all of the three succeeding nerves4 ,the anterior nerve of this plexus is distributed to the abdominal muscles4 ,an anterior branch is given off to the sartorius4 ,a large cutaneous branch enters between the sartorius and the ilio-trochanteric eminence1 and supplies the outer and the upper surface of the upper thigh region4 ,several short branches are given off from the middle1 or main1 mass of the crural plexus to the ilio-trochanteric1 or gluteal1 muscle4 ,another nerve passes over the side of the sartorius adjacent to the femoro-tibialis1 or extensor femoris1 and supplies the ilio-tibialis1 or gluteus primus4 ,the rest of this section of the crural nerves pass in a distal direction over the inner and front side of the cutaneous nerve and enter the ilio-femoralis1 or gluteus medius1 the ambiens and the femoro-tibialis muscle4 ,the furcalis nerve comes out between the last two lumbo-sacral vertebr4 ,the obturator nerve springs from several roots4 ,the anterior root of this nerve comes from the main trunk of the crural plexus1 and its last root from the furcalis nerve4 ,the obturator nerve extends in a ventral direction from the plexus1 then horizontally on the inner surface of the abdominal cavity4 ,it gives off twigs to the obturator muscle and then passes through the obturator foramen4 ,after leaving the abdominal cavity it gives branches to the accessorius1 the obturator1 and1 the pubio-femoral1 or adductor longus muscle4 ,the crural plexus gives off another large nerve trunk which extends downward4 ,shortly after emerging from the plexus it gives off a muscular branch to the ilio-femoralis1 or gluteus medius muscle4 ,it then passes between this muscle and the shaft of the femur1 to the inner posterior surface of the thigh1 and to the inner surface of the knee4 ,it gives off a branch to the structures of the knee4 ,at the knee this nerve terminates in several branches1 some of which pass to the inner surface of the tibial head1 the internal lateral ligament1 the periosteum1 the internal condyle1 and finally to the upper part of the head of the gastrocnemius muscle4 ,the main part of this nerve passes downward as the cutaneous nerve1 along the inner surface of the lower thigh4 ,the ischiadic plexus 7,fig4 #fd1 ,no4 #da7 has five to six roots1 which fuse into the ischiadic trunk4 ,this main trunk extends out of the abdominal cavity1 through the ischiadic foramen1 close behind the anterior trochanter of the ilium 7,fig4 #fe1 ,no4 #a74 ,it gives a branch to the external ilio-femoral or gluteus medius1 and a branch to the post-acetabular portion of the ilio-tibialis1 or gluteus primus muscle4 ,the main trunk 7,fig4 #fi1 ,no4 #ac7 passes downward to the lower portion of the thigh4 ,in this course there are two branches which run parallel to the femoral artery and the femoral vein4 ,it gives off a small muscular branch to the accessorius1 and further down gives off a long slender branch to the outside of the knee-joint4 ,it gives off a lateral cutaneous branch 7,fig4 #ff1 ,no4 #g7 to the posterior outer portion of the lower thigh4 ,it supplies motor fibers to the external head of the gastrocnemius muscle4 ,at the knee region the ischiadica divides into three parts4 ,the largest branch 7,fig4 #fi1 ,no4 #ad7 passes with the tendon of the ilio-fibularis1 or biceps femoris muscle1 through a loop1 the biceps band1 and lies on the upper lateral surface of the fibula4 ,it is covered by the external head of the gastrocnemius muscle4 ,it innervates the three posterior muscles of the lower thigh1 and then divides into two branches4 ,one1 the superficialis peroneus 7,fig4 #fi1 ,no4 #af7 passes with the profundus nerve1 forming a double trunk and occupying the tibio-fibular groove on the antero-lateral side4 ,it passes over the transverse ligament and the tibio-metatarsal joint1 and after sending small branches to the structures of the tibial side of the metatarsus1 it ends as a cutaneous nerve on the upper side of the third and the fourth toe4 ,the other branch is the peroneus profundus1 which separates from the peroneus superficialis and passes downward in company with the tendons1 under the transverse ligament1 and then along the anterior upper surface of the metatarsus1 where it innervates the muscles of that region4 ,it gives branches to the malleolus1 to the tendons of the third toe1 and to the median part of the second toe1 and supplies the cutaneous structures of the third and the fourth toe4 ,the third branch of the ischiadica1 a long nerve1 is given off just after the ischiadica passes through the loop4 ,it passes downward between the two peroneal nerves4 ,it is covered by a sheath4 ,it passes over the posterior outside rim of the intertarsal joint and innervates the tendon sheath4 ,the main portion of this nerve is located on the anterior surface of the tendon ,achillis1 and passes down on the plantar side1 and innervates the periosteum and all plantar foot muscles4 ,it finally radiates to the plantar surface of the three anterior toes4 ,the integument of the toes is sparingly supplied with nerves4 ,the nerve trunks that do not pass through the biceps band1 or loop can be divided into a medial 7,fig4 #fi1 ,no4 #ae7 and a lateral 7,fig4 #fi1 ,no4 #ag7 portion4 ,the medial portion 7,fig4 #fi1 ,no4 #ae7 soon divides into numerous branches which supply the muscles of the posterior and the inner portion of the thigh4 ,a rather large1 long branch passes downward along the tendon of the plantar muscle1 which lies on the posterior median edge of the tibia1 and gives off twigs to the median and posterior part of the intertarsal joint1 supplying the periosteum and other structures and the adjacent skin4 ,it passes downward along the outer side of the medial metatarsal insertion of the tendon ,achillis4 ,the fifth branch is given off from the second trunk and lies laterally4 ,it is covered by the external head of the gastrocnemius1 passes along the vena saphena1 and gives off a short main branch to the inner side of the intertarsal joint4 ,the main part passes the tibial side of the joint1 becomes subcutaneous1 and finally innervates the two plantar muscles4 ,a lateral ascending inner branch innervates the flexor perforatus digitorum1 and1 in company with an outer branch1 the external head of the gastrocnemius1 and also the flexor pedis perforatus4 ,the plexus pedundus is formed from the spinal nerves coming out of the plexus ischiadicus4 ,these fibers emerge caudalward and are directed horizontally4 ,they frequently anastomose with each other1 especially on the pubic rim and on the outside of the plexus ischiadicus4 ,these branches are deeply imbedded in the kidney substance and innervate the pubio-coccygeus1 or depressor coccygis lateralis1 the ilio-coccygeus1 the transversalis1 the sphincter1 and other muscles of this region1 and the skin of the anal region4 ,,the ,,brain ,the ,brain ,coverings4--,the cerebro-spinal axis of birds is similar to that of mammals4 ,the meninges of the brain are three in number1 dura mater1 arachnoid1 and pia mater4 ,the dura mater is the thickest4 ,it is constructed of white fibrous connective tissue1 and lines the cranial cavity4 ,thus it serves as an internal periosteum4 ,it is continuous with the spinal dura mater at the foramen magnum1 and is also prolonged as a sheath of the nerves4 ,in birds of flight where the air-sacs and reservoirs are developed to the highest state1 ,sappy finds that1 8just as the medullary tissue is replaced by air in the bones of birds1 so might it be imagined that the subarachnoid fluid is also replaced by air around the spinal cord10 and observations justify the correctness of this statement4 ,the dura mater measures exactly the volume of the marrow in birds2 so that there does not exist between the fibers and the nervous surface any space for an accumulation of liquid4 ,this anatomical fact is sufficient to demonstrate the absence of subarachnoid fluid in the bird4 ,in denying the existence of this fluid1 it ought to be added that in this class of vertebrates1 the spinal prolongation is covered by a triple envelope2 and that between the pia mater and the dura mater is a thin transparent membrane1 which is lubricated by a serous fluid4 ,this fluid however does not collect2 it only moistens the arachnoid membrane4 ,the arachnoid is located between the dura mater above and the pia mater below4 ,the pia mater adheres closely to the nerve tissue4 ,the falx cerebri exists in fowls and in turkeys4 ,it has the form of a segment of a circle1 and extends from the middle of the interval of the openings for the olfactory nerves to the tentorium cerebelli4 ,the falx cerebelli is absent4 ,the tentorium is small and is sustained by a bony plate1 and there are in addition two folds1 one on each side1 that separate the hemispheres from the tubercula quadrigemina4 ,owing to the absence of the falx cerebelli1 the meninges lie close together4 ,the falx cerebri is ossified in birds4 ,the ,brain ,structure4--,the brain 7,fig4 #fb1 ,c and ,fig4 #ge1 ,a and ,c7 is made up of three principal parts3 the cerebrum1 the cerebellum and the medulla oblongata4 ,in a fowl of medium size the brain weighs about #aej grains4 ,the pons varolii is absent in birds4 ,the crura cerebelli 7,fig4 #ge1 ,no4 #i7 are immediately connected with the corpora restiformia4 ,the lower face of the isthmus is convex posteriorly2 in front1 the tubercula bigemina 7,fig4 #ge1 ,no4 #d7 are united to each other by a comparatively large transverse cord1 formed by the optic nerves intercrossing in the median line4 ,the superior face of the medulla oblongata is depressed above to constitute a fourth ventricle2 in front of this ventricle are the tubercula bigemina1 or optic lobes4 ,these two voluminous tubercles are separated from each other above1 where they embrace the cerebellum1 and are salient on the sides of the lower face4 ,they are hollow internally1 and communicate with the aqueduct of ,sylvius4 ,the thalami optici are not well developed4 ,a large transverse fissure divides the cerebrum from the cerebellum 7,fig4 #ge1 ,no4 #e74 ,the optic chiasm 7,fig4 #ge1 ,no4 #ae7 behind which lies the hypophysis 7,fig4 #fb1 ,no4 ,c1 #bj7 covers the region of the middle brain4 ,the large transverse fissure is the dividing line between the hemispheres and the optic lobes4 ,if the hypophysis be removed there will be observed a slit surrounded by gray matter which is called the tuber cinereum et infundibulum 7,fig4 #ge1 ,no4 #ah74 ,on the pars commissuralis and the after brain there are visible the roots of the fifth1 the ninth1 the tenth1 and the twelfth pairs of cranial nerves4 ,close beside the median furrow which extends to the front part of the long furrow of the spinal cord there is observed the third pair of cranial nerves1 which have their origin in the middle brain4 ,the fourth pair of cranial nerves extend from the roof of the middle brain on both sides between the middle brain and the optic lobes4 ,these nerves finally emerge and become visible on the ventral surface4 ,the sixth nerve is visible near the middle furrow and almost in the middle of the pyramids1 and near the roots of the fifth1 the seventh1 the ninth1 the tenth1 and the twelfth pair of cranial nerves4 ,,the ,,divisions ,,of ,,the ,,brain 7,thalamus 7,pineal body 7,infundibulum 7,hypophysis ,forebrain 7,optic tract and chiasm 7,cerebral hemispheres 7,olfactory lobes 7,third ventricle 7,lateral ventricles 7,peduncles of the cerebrum ,midbrain 7,optic lobes 7,aqueduct 7,medulla oblongata ,hindbrain 7,cerebellum 7,fourth ventricle ,the medulla oblongata 7,fig4 #fb1 ,no4 ,c1 #a2 ,fig4 #ge1 ,a and ,c7 terminates anteriorly in the pars commissuralis and the pars peduncularis4 ,as the spinal cord approaches the head there is a gradual swelling1 or lateral thickening1 which merges into the medulla oblongata4 ,the superior and the inferior surface of the medulla oblongata 7,fig4 #ge1 ,no4 ,a1 #a and ,c1 #ag7 are flattened4 ,there is a shallow furrow and a slight swelling at the point where the hypoglossal nerve emerges4 ,the central canal of the spinal cord gradually comes closer to the upper surface and communicates with the fourth ventricle1 at which point the posterior raphe is shortened and the sulcus longitudinalis posterior becomes shallow4 ,at the point where the central canal terminates in the fourth ventricle there is a ,v-shaped point called the calamus scriptorius 7,fig4 #ge1 ,no4 #b74 ,the fourth ventricle is located on the upper wall of the medulla oblongata below the cerebellum1 and is bounded laterally by the peduncles of the cerebellum4 ,it is marked posteriorly by the calamus scriptorius and anteriorly by the valve of ,vieussens4 ,the valve of ,vieussens is located at the posterior end of the aqueduct of ,sylvius4 ,the posterior part of the fourth ventricle is marked by grooves or furrows4 ,extending along the central part of the floor of the fourth ventricle there is a sulcus1 or groove1 called the sulcus centralis1 which divides the superior pyramids4 ,on the median lateral sides there are two points of gray substance which form the al cinere4 ,the roots of the pneumogastric1 the glosso-pharyngeal1 and the spinal accessory may be traced to the al ciner and the gray matter of the ridges of the medulla oblongata4 ,the sixth pair of the cranial nerves emerge from the medulla near the sulcus centralis and to the side of the auditory nerve4 ,part of the trigeminus emerges from the rim of the furrow next to the ridge4 ,at the outer border of the medulla are observed the thick ends of the roots of the pneumogastric1 the spinal accessory1 the glosso-pharyngeal1 and the auditory facialis4 ,on both sides of the sulcus longitudinalis inferior are found the inferior pyramids1 or pyramidal columns4 ,these pyramids become expanded near the origin of the third pair of nerves and merge into the cerebral peduncles1 or crura cerebri4 ,the pyramidal fibers may also be traced to the optic lobes4 ,the roots of the abducens are found at a point between the crura cerebri and the optic lobes4 ,the third pair lies to the side of this1 and the roots of the trigeminus are adjacent to those of the third4 ,a bundle of fibers from this region pass into the cerebellum and form the crura cerebelli2 others pass into the cerebellum from the side1 spreading out in fan-shaped radiation1 and forming the white central substances peculiarly arranged1 called the arbor vit1 or tree of life4 ,a third bundle fuse with the crura cerebelli anteriorly1 and pass into the peduncles of the cerebrum1 or crura cerebri4 ,the gray ganglionic substance forms columns which extend the whole length of the medulla oblongata and into the cerebri4 ,the medulla oblongata contains numerous centers which preside over various visceral functions as deglutition1 respiration1 thermotactic1 secretory1 cardiac1 and digestion4 ,in the medulla as in the spinal cord there are five main groups of cells4 ,first1 the posterior or upper horns1 from which come the somatic sensory nerves4 ,second1 ,clark's cells1 located centrally1 which are the origin of the ganglionated splanchnic nerves4 ,third1 cell groups of the lateral horns which are the center for the non-ganglionated splanchnic nerves1 and certain other nerves for the viscera1 including the enteric muscles4 ,fourth1 cell groups of the anterior horns1 which are the center of all somatic voluntary muscles4 ,fifth1 groups of single cells probably belonging to the posterior horns which are probably centers for other splanchnic nerve fibers4 ,illustration3 ,,fig4 #gg1 ,a4 ,g1 ,a section through the tuberculum bigeminum4 #a1 ,pia mater4 #b1 ,nerve fibers4 #c1 ,fine granular ground substance4 #d1 ,thin layer of small cells4 #e1 ,fine granular ground substance4 #f1 ,a second thin cell layer4 #g1 ,fine granular ground substance4 #h1 ,third thin cell layer4 #i1 ,fine granular ground substance4 #aj1 ,fourth widely extended cell layer4 #aa1 ,a fine granular layer4 #ab1 ,a thick layer of spindle cells4 #ac1 ,a layer of medullated nerve fibers4 #ad1 ,ependemal cells4 #ae1 ,the sinus4 ,h1 ,a transverse section through the medulla oblongata1 #a1 #c1 #d and #f are ganglionic centers4 #b1 ,the dorsal groove4 #h1 ,the ventral fissure4 #e1 ,the central canal4 #g1 ,fiber tracts4 ,i1 ,a transverse section through the cervical portion of the spinal cord4 #a1 ,ventral septum4 #b1 ,dorsal septum4 #c1 ,the central canal4 #d1 ,the dorsal horn4 #e1 ,the ventral horn4 ,j1 ,a section through the wall of the oil gland1 or rump gland4 #a1 ,the stroma4 #b1 ,the tubular glands some of which are branched4 ,k1 ,a section through a spike of a comb of a cock4 #a1 ,the epithelial layer4 #b1 ,a dense fibrous subepithelial layer4 #c1 ,a second fibrous vascular layer4 #f1 ,a denser central core supporting the large arteries and veins4 #d1 ,a vein4 #e1 ,an artery4 ,l1 ,a section through a lobe of the wattle of a hen4 #a1 ,the epithelial layer4 #b1 ,a dense vascular layer4 #c1 ,a vein4 #d1 ,an artery4 #e1 ,a loose fibrous vascular structure4 ,the gray matter in the cord is in the form of two commas placed with their backs together with the central canal passing between them4 ,the central canal is located in the center of the cord4 ,as the cord nears the medulla oblongata the form of the gray matter changes4 ,the second1 the third1 and the fifth ganglion centers are arranged laterally1 and show a distinct side-horn group4 ,the central canal separates the two ,clark's columns2 later the side-horn group enlarges and extends ventrally around the anterior horn group and joins on the other side in half-moon shaped formation4 ,the central ganglionic mass of the spinal cord1 the center for the enteric visceral system1 is divided into three complex parts4 ,first1 there are cell groups on both sides of the posterior raphe4 ,second1 the half-moon shaped ventral groups extending parallel peripherally described above4 ,third1 lying between groups one and two a complex group1 which possesses a large collection of cells4 ,these furnish splanchnic nerve centers1 the anterior supplying motor nerves and carrying motor impulses outward1 and the superior sensory which carry impulses to the centers4 ,the cell group of the superior horns takes a sidewise peripheral position 7,gadow74 ,the cerebellum 7,fig4 #fb1 ,c1 #b7 is located above the medulla oblongata and posterior to the cerebrum4 ,the cerebellum consists principally of a median lobe called the worm4 ,the lateral lobes are conical and rudimentary4 ,the under part of the worm forms the roof of the fourth ventricle4 ,on the upper surface of the cerebellum are numerous transverse markings 7in the hen #ac or #ad7 which divide the lobe into leaves4 ,when the cerebellum is cut lengthwise there is observed on the sectioned surface the peculiar arrangement of the white and the gray matter1 the arbor vit1 mentioned above4 ,there is a small cavity in the cerebellum which communicates with the fourth ventricle4 ,the cerebellar cortex shows four parts1 namely3 ,first1 the central part composed of white medullated fibers1 between which are arranged neuroglear cells4 ,second1 a rather reddish layer of cells of different sizes4 ,these cells are embedded in a fine ground substance and are about #j4jjc mm4 in diameter4 ,third1 a plain layer of large pear-shaped ganglion cells1 the cells of ,purkinje4 ,fine branches extend outward from the apex of these cells4 ,fourth1 an outer gray layer which consists of small multipolar nerve cells with some neuroglear cells4 ,the color of these three layers1 according to ,gadow1 depends upon the color of the plumage2 that is1 if the plumage is dark1 this layer is dark2 if light1 the layers are light4 ,the marked coloring is said to be most distinct in the second layer4 ,the anterior portion of the cerebellum consists of medullated nerves whose fibers run crosswise4 ,these are the extensions of the true cerebellar fibers1 which become fewer and fewer as they proceed anteriorly4 ,finally1 a few remaining fibers running crosswise fuse as the commissura ,sylvii1 and extend into the lobi optici4 ,a layer of nerve cells extends under these medullated nerve fibers4 ,a bundle of fibers extending from the medulla oblongata4 ,these fibers extend into the optic lobes1 form the crura cerebri1 or peduncles of the cerebri1 and also form the inferior wall1 or floor1 of the aqueduct of ,sylvius4 ,the crura are sometimes spoken of as the partes pedunculares4 ,these contain gray matter4 ,the following division is made of the ganglion of this region4 ,first1 a group of cells near the base of the peduncles1 which are divided from the ventral rim by the arciform fibers4 ,this ganglionic formation may be considered an extension from the medulla oblongata4 ,second1 a group of the ganglion cells of the lobus optici4 ,third1 a group of cells lying near the lobus opticus1 which give rise to the ascending roots of the trigeminus4 ,fourth1 a group of ganglionic cells from which spring the roots of the motores occuli1 and which lies near the middle line and under the sulcus centralis4 ,many ganglion cells are found to the right and to the left of the sulcus centralis1 which show different arrangement of the cells at different levels4 ,fifth1 a group of irregular cells which extends centrally on the superior walls of the third ventricle and to the superior part of the lobus opticus4 ,the microscopic structure of the roof of the lobus opticus1 or corpus bigeminum1 shows that the layers are arranged parallel to the pia mater and are divided into the following parts3 ,externally1 the pia mater4 ,an outer layer of very fine nerve fibers1 which lies just below the pia mater4 ,a layer of fine granular ground substance4 ,a thin layer of small cells the diameter of each of which is #j4jch mm4 ,a layer of fine granular ground substance4 ,a second thin cell layer4 ,a zone of fine granular ground substance4 ,a third thin cell layer4 ,a fine granular ground substance4 ,a fourth widely extended cell layer4 ,a fine granular layer4 ,a somewhat thick layer of spindle-shaped cells4 ,a layer of medullated nerve fibers4 ,this last is the inner layer of nerve fiber4 ,on the inner surface of this layer we find the ependymal cells1 the cells that line the cavity of the optic lobes4 ,the commissura ,sylvii form the covering of the lobi optici and join these two lobes4 ,this commissure is formed from the upper and the lower layer of nerve fibers4 ,in the commissure these fibers cross each other4 ,the hypophysis 7,fig4 #fb1 ,no4 ,c1 #bj7 lies back of the chiasm1 or optic commissure1 and below the middle of the third ventricle4 ,the infundibulum1 a pedicle-like structure1 connects the hypophysis with the third ventricle of the cerebri4 ,it contains a cavity and forms an extension of the third ventricle4 ,the hypophysis is divided into two lobes1 an anterior and a posterior4 ,the third ventricle communicates anteriorly with the lateral ventricles of the cerebri through the foramen of ,monro1 and posteriorly with the fourth ventricle through the aqueduct of ,sylvius4 ,the posterior walls of the third ventricle are relatively thick and form the posterior brain commissure4 ,the wall is thin from the commissure to the chiasm4 ,within it lie two ridges1 which connect the two hemispheres with the corpus callosum1 and1 farther anteriorly1 with the anterior cerebral commissure4 ,the space from the third ventricle and to the anterior commissure is called the lamin terminales4 ,the pineal gland1 located between the cerebri and the cerebellum1 lies against the choroid plexus1 which covers the highest point of the third ventricle4 ,the cerebrum is divided by a deep longitudinal fissure into two hemispheres4 ,the cerebrum is shaped somewhat like the heart on a playing card4 ,the lower face is somewhat flattened4 ,the upper and lateral sides are not provided with convolutions or sulci1 but are smooth4 ,the fissure of ,sylvius is faintly marked on the inferior face4 ,the olfactory lobes appear well developed and are relatively large for the size of the brain4 ,they lie close together on the extreme anterior portion in the median line4 ,the olfactory cerebral crura emerge from the cranium at the upper angle between the posterior wall1 the roof1 and the septum of the orbit1 and pass through the olfactory foramina and in grooves on the upper part of the septum2 then passing forward they penetrate the frontal structure and are finally distributed over the turbinated mucous membrane4 ,the corpus striatum is large2 it occupies nearly the entire floor of the ventricles4 ,the anterior commissure is found between the hemispheres4 ,its middle part lies in the lamina terminalis on the division between the anterior and the middle brain1 and close to the thalami optici4 ,its side extensions are rounded masses called the nervi amygdales4 ,the corpus callosum1 quite rudimentary1 lies on the posterior dorsal rim of the anterior commissure4 ,the corpus striatum forms a thin broad ridge1 which passes ventrally4 ,this structure consists of twenty-five large pyramidal cells which lie in the posterior lateral dorsal section1 and of from ten to fifteen pyramidal cells which are located in the rest of the section4 ,in addition to these two groups there are many cells about #e millimeters in diameter4 ,these lie1 six or more1 in a nest imbedded in neuroglia4 ,there is a thin layer of spindle cells near the ventral line4 ,the outer nerve nest1 or nerves amygdalis1 lies in the posterior lateral ventral part4 ,it is covered by a thin membranous layer4 ,its cells are pyramidal in shape and are from #aj to #ae millimeters in diameter4 ,the cells terminate in spindle form toward the periphery4 ,nerve fibers extend from the anterior commissure4 ,the outer wall of the corpus striatum consists of the following layers3 ,an outer white layer consisting of fine medullated nerve fibers imbedded in a ground substance containing numerous nerve cells4 ,a layer of ganglionic cells1 consisting of pyramidal cells from #aj to #ae millimeters in diameter1 of other round cells #bj millimeters in diameter1 and finally of cells only #e millimeters in diameter4 ,this layer forms a reddish line in the dorsal portion of the corpus striatum4 ,these layers form part of the median and the posterior cerebral wall of the lateral ventricle4 ,the lateral ventricle is closed except for a slit-like opening behind the posterior commissure4 ,this is the foramen of ,monro1 through which the lateral ventricle communicates with the middle1 or third1 ventricle4 ,the choroid plexus is found at the base of the lateral ventricle4 ,the wall of the lateral ventricle becomes thinner near the region of the transverse commissure on the surface toward the middle brain4 ,at this point the pia mater and the ependyma1 or the lining cells of the ventricular membrane1 form the major part of the wall4 ,the domestic fowl does not have the hippocampus4 ,the wall of the middle ventricle consists of an outer white layer1 which is arranged similarly to that of the corpus striatum4 ,the ventral rim of the wall is formed by a spiral band which consists of fine medullated fibers1 in which are imbedded a few cells4 ,the processus cerebri mammillares are also called the tubercula olfactoria4 ,from these structures extend forward the olfactory nerves1 the posterior roots of which may be traced to the walls of the lateral ventricles4 ,the structure of the processus cerebri mammillaris is made up of five layers as follows3 ,an outer layer1 which consists of colorless olfactory fibers extending in all directions4 ,a granular ground substance layer1 in which are imbedded a few cells4 ,a thicker granular layer1 on the inner edge of which are twenty large pyramidal cells with processes pointing outward4 ,a layer of closely packed cells1 in which are fine medullated nerve fibers4 ,these cells are about #e millimeters in diameter4 ,an innermost layer of ependymal cells4 ,near the hemisphere the peripheral nerve fibers and nerve cells disappear1 leaving only the ground substance of the processus to aid in the formation of the hemisphere4 ,there is a long bundle of fibers on the lower surface of the hemisphere1 which blends with the substance of the olfactory fibers4 ,the peduncles of the cerebrum 7,fig4 #fb1 ,no4 #ba7 are the slightly diverging columns of nerve tissue1 which form the anterior continuation of the medulla oblongata and disappear under the optic tracts and the chiasm4 ,,the ,,sympathetic ,,nervous ,,system ,the sympathetic nervous system commences anteriorly at the large superior cervical nerve ganglion4 ,this ganglion1 anteriorly1 brings into communication the glosso-pharyngeal1 the pneumogastric1 or vagus1 and the sympathetic system4 ,the following nerve trunks emerge from the superior cervical nerve ganglion3 a large trunk fusing with the vagus and directed downward1 accompanying and surrounding the carotid artery2 a second large trunk fusing with the recurrent pharyngeus and the glosso-pharyngeus2 a third trunk which merges with the hypoglossal2 finally several trunks which are distributed to the head4 ,the temporo-lacrimalis1 one of the large sympathetic nerves of the head1 as it extends from the cervical nerve ganglion1 receives branches from the ganglion radicis vagi4 ,this nerve1 passing between these two ganglions1 extends horizontally forward and outward through a foramen1 crossing the glosso-pharyngeus4 ,near the ,fallopian canals it crosses the facial nerves1 lies supero-laterally1 and receives a short branch from the facial nerve whose fibers are traceable to the geniculate ganglion4 ,it also receives a branch from the recurrent maxillaris4 ,this nerve accompanies the external ophthalmic artery forming around it a network of fibers1 called the external ophthalmic plexus4 ,it lies outside and downward from the optic nerve1 sends fine branches to the external ophthalmic artery and to the masseter artery1 and extends along with a small branch of the superior maxillary nerve to the skin of the outside rim of the eye cavity4 ,the ophthalmic plexus1 a second trunk extending to the head1 enters in its course1 anteriorly1 the lacrimal plexus4 ,its fibers also supply the lacrimal gland1 and finally anastomose with the second recurrent branch of the trigeminus4 ,the sympathetic caroticus cephalicus nerve1 a third trunk extending to the head1 after emerging from the large superior cervical nerve ganglion1 receives some small branches from the glosso-pharyngeal ganglion1 and then enters1 in a horizontal manner1 a foramen1 the canalis caroticus externus1 located in the lower part of the basi-occipital and the sphenoid bone4 ,the anterior opening of this foramen1 or canal1 is close to the posterior part of the pterygoid bone4 ,inside this canal the sympathetic caroticus cephalicus receives a small branch which extends in a straight line from the basal part of the facial nerve4 ,after receiving this branch1 the nerve trunk1 passing to the ear drum1 lies close to the petrosum and the sphenoid4 ,it is covered by the masseter muscle4 ,the carotic ganglion is located at the point of the fusion of the caroticus cephalicus with the main trunk4 ,at this point the caroticus cephalicus divides into two branches4 ,the first is the superior recurrent nerve1 which lies close to the upper surface of the al of the sphenoid1 passes between the obliquus externus and the orbital wall1 around the eyeball1 and finally into the orbital septum and the internal muscles of the eye4 ,it communicates with the ophthalmic nerve and sends twigs to the lacrimal gland1 the gland of ,harder1 the upper eyelid1 and the nose4 ,the orbito-nasale ganglion is located where these nerves communicate near the nasal region4 ,the second branch of the sympathetic caroticus cephalicus is the inferior recurrent nerve4 ,this branch passes forward and dorsally from the pterygoid bone to a point where the upper rim of the rising wings of the jaw bone meets the sphenoid rostrum4 ,in this course1 some branches are given off to the pharynx1 one branch near the lacrimal gland1 and a branch which communicates with the superior maxillary nerve just before the nerve enters the jaw bone4 ,the spheno-palatine ganglion is at the point of fusion4 ,the terminal branches of the spheno-palatine are distributed to the hard palate1 the nose1 and the lacrimal gland4 ,from the large cervical nerve ganglion and near the roots of the caroticus cephalicus are given off a few small nerve fibers which pass alone to the pharynx or accompany the jugular nerve branches1 and fuse with the main trunk of the caroticus cephalicus nerve4 ,from the large superior cervical nerve ganglion the sympathetic trunk extends downward toward the thorax4 ,it is covered deeply with muscles4 ,this portion is known as the cervical sympathetic nerve trunk4 ,a trunk lies on each side of the cervical vertebr4 ,the large thoracic nerve ganglion1 the inferior cervical1 is located along this trunk at the entrance of the thorax4 ,from this ganglion there is given off the recurrent cardiacus which supplies the heart4 ,the end branches of the sympathetic nerve trunk blend with the pneumogastric nerve4 ,the inferior nerve ganglion is the ganglion cardiacum4 ,near this ganglion is found a nerve plexus in which there are imbedded peripherlistic ganglia4 ,this thoracic plexus1 accompanying the collica artery1 passes to the abdominal region1 supplying the intestines and taking part in the formation of the abdominal plexus4 ,the abdominal plexus is located near the anterior portion of the kidneys4 ,its fibers are directed mainly downward to the visceral organs4 ,the large intestine1 the rectum and the copulatory organs receive branches4 ,these latter branches take part in the formation of the pedunda nerve plexus4 ,some branches of this plexus1 follow the branches of the posterior mesenteric artery4 ,the thoracic trunk 7,fig4 #fd1 ,no4 #db7 of the sympathetic is double4 ,the anterior portion gives off an anterior splanchnic nerve1 or plexus 7,fig4 #fd1 ,no4 #dc7 which accompanies the celiac axial artery to the gizzard and liver1 communicating with the pneumogastric4 ,the posterior splanchnic nerve is intimately combined with the adrenal body1 and the testes1 or the ovary 7,fig4 #fd1 ,no4 #de74 ,intestinal branches accompany those of the mesenteric arteries 7,fig4 #fd1 ,no4 #df74 ,other branches supply the kidneys1 and communicate with long branches of the spinal nerves destined for the cloaca and adjacent parts1 and thus form a plexus similar to that found in mammals4 ,,functions ,,of ,,the ,,nervous ,,system ,according to function1 the nerves composing the trunks are divided into afferent and efferent4 ,the afferent nerves are those that convey the impulses from the periphery of the body to the nerve center1 which are located in the brain or in the spinal cord4 ,the impulses conveyed are those of special senses1 as sight1 hearing1 taste1 touch1 and smell4 ,impulses producing sensation pleasurable or painful come from the skin1 the muscle1 or the viscera4 ,the efferent nerves are those which convey impulses from the nerve centers to the periphery4 ,these impulses may be motor as those going to the muscle cells of the skeletal muscles1 the viscera1 or the blood-vessels4 ,these motor impulses make movements in these organs possible4 ,in the blood-vessel they result in the control of the caliber of the vessel4 ,these impulses may be of an inhibitory character1 as in slowing the heart4 ,they may be secretory impulses stimulating the gland to activity or regulating metabolism4 ,the ganglia are nerve centers which receive and generate impulses2 the nerve trunks are filaments which convey impulses4 ,the gray matter of the cord described above is the ganglionic portion1 and the outer white matter is made up of nerve fibers which convey impulses from one part of the cord to another1 or to and from the brain4 ,the nerves that have their roots in the spinal cord superiorly1 are sensory2 that is1 they convey the sensory impulses from the periphery to the cord ganglion and to the brain4 ,they have a ganglion just outside the cord4 ,the nerves that have their roots in the spinal cord inferiorly2 that is1 they convey motor impulses from the nerve centers to the periphery4 ,the function of the inferior roots is to supply all the voluntary muscles as well as the oviduct1 the intestines1 and other hollow viscera1 including the blood-vessels with the power of movement4 ,many of these fibers pass to the sympathetic ganglion and are distributed as sympathetic nerve fibers4 ,the cord is divided into different tracts1 that is1 certain groups of fibers convey certain kinds of impulses4 ,the superior column of the cord conveys to the cerebrum such impressions as temperature1 pressure1 and muscular tension4 ,the fibers of the lateral columns carry sensations of pain4 ,the fibers of the direct cerebellar tract carry impulses which result in the maintenance of the equilibrium of the body4 ,all the voluntary impulses originate in the cerebrum1 pass through the cerebellum and travel direct to the bulb2 they then pass over to the opposite side1 and travel by the crossed pyramidal tract to the multipolar cells of the inferior horn of the spinal cord1 and transmit the impulse through motor fibers that originate at that point in the cord4 ,all sensory impulses enter the brain on the side opposite their origin1 and all motor impulses leave the brain on the side opposite that to which they are distributed4 ,injury of the motor area of the right side of the brain leads to paralysis of the left side of the body4 ,an impulse of the vasomotor nerve travels in the lateral column of the cord4 ,a nerve impulse may originate in the brain and be modified in passing through a ganglion in the spinal cord or in the sympathetic system4 ,the system of reflex action is as follows3 first1 an efferent nerve which conveys the impulse from the periphery to a nerve center2 second1 a ganglion1 or nerve center1 to receive the impulse and generate other impulses2 third1 an efferent nerve to convey the impulse from the nerve center to the periphery4 ,the following is an example of reflex action4 ,the foot of a fowl is pierced with a pin4 ,the sensory impulse is conveyed by sensory nerve fibers to the nerve centers4 ,in this center the ganglionic nerve cells generate a motor impulse which is sent back through the motor nerve fiber to the muscles controlling the part4 ,the result is that the muscle contracts and jerks the foot4 ,there are many functional centers located in the medulla oblongata4 ,destruction of this part of the system results in instant death of the bird4 ,in addition to furnishing a path for fibers carrying impulses from the body to the cerebrum1 it furnishes a large number of centers for such functions as respiration1 swallowing1 secretion1 temperature1 and vasomotor and cardiac activity4 ,the function of the cerebellum is principally that of cordination4 ,it brings about harmony and rhythm in muscular movements4 ,if the cerebellum be removed1 the bird can no longer walk4 ,it has lost1 with this removal1 all power to cordinate4 ,the cerebrum of the bird has no convolutions1 and the gray1 or ganglionic1 portion is thin1 indicating low power of intelligence4 ,there are certain areas presiding over other functions1 as motor areas1 sensory areas1 and so on4 ,a careful study of the brain of the fowl shows us that the centers presiding over sight and smell are well developed4 ,the olfactory bulbs are the centers of the sense of smell4 ,the optic thalamus is the center of the sense of sight4 ,the sympathetic nerve system transmits impulses to the involuntary muscular structure of all organs1 including those of the intestinal tract1 the blood-vessels1 and perhaps also the glands4 ,,esthesiology ,,the ,,sense ,,organs ,the five special senses are seeing1 smelling1 tasting1 hearing1 and feeling4 ,,the ,,organ ,,of ,,sight ,the sense of sight in the bird is well developed4 ,the eye 7,fig4 #bf1 ,d1 ,e and ,f71 the organ of sight1 is relatively large1 round laterally1 and rather flattened antero-posteriorly4 ,it is located at the side of the head4 ,the eyeball is only slightly movable4 ,the septum interorbital separates the two eyeballs laterally4 ,as in mammals1 the eyeball has three coats1 which are from inside to outside1 the retina1 the choroid1 and the sclera4 ,the sclerotic coat is completed anteriorly by the cornea with which it forms a union called the corneo-scleral juncture4 ,around the cornea the sclerotic coat contains a ring of osseous scales varying in number from twelve to twenty4 ,the sclera may become ossified posteriorly1 forming an osseous sheath around the optic nerve4 ,the pecten is a vascular comb-like membrane stretching from the nervous opticus to the crystalline lens4 ,the choroid coat is always black4 ,the pupil in the hen is also black and round4 ,the iris contains striated muscular fibers4 ,the membrana nictitans1 located at the inner angle is well developed4 ,it is moved by two muscles 7,fig4 #bf1 ,no4 ,b1 #g1 #h1 #aj74 ,the lacrimal gland and the gland of ,harder are present4 ,there is no meibomian gland4 ,the tears are secreted by the lacrimal gland and are drained away from the fore part of the eyeball by two small canals which extend into a lacrimal sac4 ,from this sac there extends a tube into the nasal cavity called the lacrimal duct4 ,the lower lid is the larger and often incloses a small cartilaginous plate4 ,the conjunctiva is a true mucous membrane which covers the anterior portion of the eye cavity attaching to the cornea-scleral juncture4 ,the choroidea is rich in pigment4 ,on its inner surface lies the dark pigment layer of the retina4 ,the corpus ciliare1 that part of the choroid coat bearing the ciliary processes1 consist of numerous folds4 ,the ciliary muscles are arranged obliquely4 ,each consists of three digitations4 ,the iris is covered on the posterior side with pigment1 the color of which determines the color of the eye4 ,the yellow pigment of the iris has been said to be due to carotin and xanthophyll and the black pigment to melanin4 ,the enlarging and the contracting of the pupil is brought about by muscles4 ,the reduction of the pupillary caliber is due to the sphincter pupillary muscle4 ,it is said by some anatomists that the muscles controlling the caliber of the pupil in the bird furnish voluntary motion and that the capability of accommodation of the eyes is greater in birds than in mammals4 ,the retina contains no blood-vessels2 otherwise the structure is similar to that of mammals4 ,the crystalline lens is flattened on the corneal side and is convex posteriorly4 ,the lens epithelium develops into fibers in the parts close to the equator1 and are almost perpendicular to the eye axis4 ,the corneal portion is relatively small4 ,the sclerotic coat is dense and white4 ,it is divided into three layers4 ,it is thin and flexible1 and somewhat elastic posteriorly4 ,it has an internal layer of hyaline cartilage4 ,anteriorly its form is maintained by the circle of osseous plates mentioned above4 ,these plates1 interposed between the exterior and the middle layer1 are located immediately behind the cornea4 ,the scales are thin and of oblong quadrate shape1 being elongated from before backward4 ,the choroid coat is a membrane loosely cellular and highly vascular4 ,it is impregnated by a black pigment4 ,opposite the bony circle the choroid separates into two layers4 ,the external layer is the thinner and adheres at first firmly to the sclerotic2 it passes forward to become continuous with the iris4 ,the inner layer is thicker than the external4 ,the two layers are made up of radiating fibers which terminate anteriorly in the ciliary processes1 the ends of which are adherent to the capsule of the crystalline lens4 ,the iris is delicate in structure4 ,it is composed of a fine network of interlacing fibers4 ,the ciliary nerves and blood-vessels run in the form of single trunks between the choroid and the sclerotic1 and terminate anteriorly in a ring-shaped plexus for the supply of the iris and the muscular circle of the cornea4 ,as stated before1 the pupil in the fowl is round1 but in the goose it is elongate transversely2 and in the owl1 a vertical oval4 ,the optic nerve approaching the sclerotic coat becomes altered into a conical extremity1 which enters a sheath and is directed downward and obliquely forward4 ,the extremity of the optic nerve in the interior of the eye presents a white narrow streak4 ,branches of the opthalmic artery enter the eye between the lamina of the retina1 along the whole extent of the oblique slit1 and penetrate the fold of the pecten upon which they form a delicate ramification4 ,the crystalline lens is of soft texture4 ,it is inclosed in a capsule and is nearly round4 ,it adheres very firmly in the depression in the anterior part of the vitreous humor4 ,the capsule is lodged between two layers of hyaloidea1 which as they recede from each other1 leave around its circumference the sacculated canal of ,petit4 ,the cornea is of horny consistency and is transparent4 ,light thus rapidly passes through it to the posterior part of the eye4 ,the vitreous chamber1 lying back of the crystalline lens1 contains a clear jelly-like substance4 ,,the ,,organ ,,of ,,hearing ,the ear1 the organ of hearing1 has in the fowl no conchal cartilage4 ,the external auditory meatus1 or canal opening1 is found on each side of the head1 and is usually guarded by a few stiff1 short feathers4 ,in some kinds of birds these feathers are capable of being erected so as to direct the waves of sound into the inner ear4 ,the outer entrance of the ear contains glands4 ,this canal is short4 ,it leads to the drum1 which is somewhat convex from the outside1 and which has a membrane forming a complete curtain stretched over the outer part4 ,the irregularly formed drum has connection with the air-containing cavity of the skull1 and by a thin cartilaginous canal1 the ,eustachian tube1 with the pharynx4 ,the auditory ossicles are represented by only a single bone1 called the columella1 which most closely represents the stapes of mammals4 ,this is attached by processes of cartilage to the tympanic membrane4 ,owen considers these cartilages as representing the malleus of mammals4 ,huxley on the other hand considers them to represent the incus4 ,originating from the processes is a small muscle which is attached to the drum4 ,this is by ,shufeldt considered the ,tensor tympani4 ,the drum cavity through the fenestra vestibularis and cochlearis is connected with the labyrinth4 ,the inner ear consists of a membranous labyrinth1 surrounded by a spongy bony structure--the bony labyrinth4 ,in it are recognized the vestibulum1 the three half-circle shaped canals1 and the cochlea4 ,the superior semicircular canal is the largest4 ,the acoustic nerve enters at the end of the canals near the ampull4 ,the nerves are supported in delicate vascular membranes lining the canals and slightly projecting into the ampull4 ,illustration3 ,,fig4 #gh4--;,diagram of the inner ear4 #a1 ,the integument4 #b1 ,the superior semicircular canal4 #c1 ,the external canal4 #d1 ,the horizontal canal4 #e1 ,the ampulla4 #f1 ,the obtuse osseous conical cochlear cavity4 #g1 ,the ,eustachian tube4 #h1 ,the tympanum4 #i1 ,filaments of the auditory nerve4 ,the vestibulum is a small irregular cavity which communicates with the arcades and the cochlea1 and through the fenestra vestibularis with the drum cavity4 ,the endolymph of the vestibulum contains microscopic crystals of calcium carbonate4 ,the semicircular canals are relatively larger and thicker than in mammals4 ,the ampull in the upper and back part are separated by walls4 ,the cochlea is an obtuse conical tube-like structure slightly curved at the blind extremity with the concavity directed backward4 ,it contains a membranous lining4 ,at this point the cochlea is broadened and accommodates a branch of the auditory nerve4 ,this nerve spreads out in fine filaments upon the surface of the tubes4 ,the hollow space of the cochlea is divided by a spiral partition1 making two chambers1 the scala vestibuli and the scala tympani4 ,these walls extend from the beginning of the cochlea4 ,the tympanic cavity is formed by the occipital1 the basi- and alisphenoids1 the petrosal portion of the temporal bone4 ,it represents the stapedial canal leading to the foramen ovalis and the pneumatic apertures by which the air from the ,eustachian tube is conducted to the precranial diplo4 ,,the ,,organ ,,of ,,smell ,the nose is the seat of the peripheral portion of the organ of the sense of smell4 ,the terminals of the olfactory nerves1 which receive the impressions of odors1 are broadened in the mucous membrane of the walls of the anterior nares4 ,there are no ethmoidal volutes1 or sieve-like structure1 in birds4 ,the nerve extends from the anterior portion of the brain in cone-shape1 finally dividing into filaments which are distributed over the mucous surface of the turbinated bones4 ,,the ,,organ ,,of ,,taste ,the most important part of the organ of taste is the tongue4 ,in birds the dorsum of the tongue is covered by a thick stratum corneum1 a heavy layer of stratified squamous epithelium4 ,the tongue1 therefore is not in birds so well adapted for the perception of taste as it is in mammals4 ,the lingual branch of the trigemini is lacking in birds4 ,this fact makes the ninth pair1 or the nervi glosso-pharyngei1 the exclusive nerves of taste4 ,there is an opinion ventured by one anatomist that1 since the first and the second branch of the fifth pair1 or trigemini1 have terminal filaments in the hard palate1 they may furnish fibers for the sense of taste4 ,there are many taste cells on the tongue and on the dorsal palate4 ,,the ,,organ ,,of ,,touch ,the peripheral parts of the organ of touch in the fowl are the skin and the feathers4 ,in a few birds special touch and taste perception can be supplied by the edge and point of the beak4 ,in the skin of birds are found numerous sensory nerve endings for tactile sense4 ,the sensory nerves1 which provide the sense of touch1 usually terminate in one of two forms4 ,the first are the ,herbst's bodies1 which in many respects are similar to the ,picinian bodies4 ,herbst's touch corpuscles are found on all parts of the skin2 they are especially numerous in the region of the tail and of the wing4 ,in the wing they are particularly numerous in the region of the flight feathers4 ,they occur in large numbers in the periosteum of the anterior tibial region and in the mucous membrane of the cloaca and of the generative organs4 ,they are numerous in the conjunctiva and on the surface of the tongue4 ,they are also found in the gums and in the beak4 ,herbst's corpuscle is made up of a central fiber-shaped part with a smooth extension of the axis cylinder of its nerve 7,fig4 #bi1 ,g74 ,this central fiber is surrounded by a peculiar protoplasmic body4 ,outside of this there is a double row of cubical cells which surround the axial part4 ,these are close together4 ,outside of these there occurs a concentric lamellar layer1 which contains cells4 ,in the periphery these lamell become more distinct and contain larger but fewer cells4 ,the capsule is made up of very thin layers1 which are continued into the perineural layer4 ,each body contains a thin outer zone4 ,the nerve fiber passes in a regular manner from the axis cylinder1 the myelemma1 and the sheath of ,schwann1 and as a delicate nerve twig is surrounded by a sheath consisting of several perineural layers4 ,as it enters the center of the touch corpuscle1 it loses its myeline sheath near the base of the body1 and the terminal fiber becomes flattened4 ,its rim is directed toward the two rows of cubical cells1 and it ends in a rounded knob4 ,the touch corpuscles are the largest in the mucous membrane of the cloaca and smallest in the skin4 ,hess has found these touch corpuscles in the large filiform papill on the side of the tongue and a few on its lower surface4 ,they are also found in the soft skin of the edges and inner borders of the beak4 ,,structure ,,of ,,appendages ,the skin of the fowl is very thin and does not contain oil glands or sweat glands4 ,in the fowl the oil is supplied by a tail or rump gland1 the glandula uropygii 7,fig4 #ce1 ,no4 #af74 ,this gland is round or oval in shape1 and about the size of a pea and consists of two lobes4 ,it is of the tubular variety with a teat1 which1 in most instances has two openings4 ,a medium septum divides the gland into two halves4 ,the oil secreted by the columnar epithelial cells is collected in a body cavity located in the center of the gland2 this has a duct extending to the surface4 ,the bird by squeezing out a quantity of this oil into its beak oils the feathers1 passing the beak over them1 one by one4 ,the oil renders the feathers practically impervious to water4 ,it is necessary for the bird to give proper attention to its plumage in order that the feathers appear in prime condition4 ,should there be a disease of the oil gland1 or should the bird become ill and neglect its toilet the result is an unkempt appearance of the plumage1 the feathers becoming rather rough and more or less injured by the weather4 ,the subcutis is well developed and furnishes to the cutis great capability for movement1 which is necessary for the rising and falling of the feathers4 ,the corneum is very thin4 ,papillary bodies are present only in a very few places1 such as the region about the eye and on the toes4 ,where the toes touch the ground in walking there are large wart-like thickenings of the epithelium4 ,in most birds the shanks are unfeathered4 ,the epidermis on the feathered parts of the skin is thin1 dry on the surface1 and abounds in continuous scales4 ,the stratum corneum is very thick on the horny sheath of the beak1 on the top of the toes1 on the spurs of the cock1 and on the scale plates that cover the skin on the shanks4 ,the feathers of birds serve the same protective purpose as hair on mammals4 ,in cold weather the skin muscles controlling the feather movements contract2 thus the feathers become ruffled much as we observe the hair standing erect on horses under similar conditions4 ,by increasing the dead air space around the body1 the radiation of heat is retarded1 and the body kept warmer4 ,the corneum of the skin is not usually rich in blood-vessels2 however1 in the domestic fowls there is in the comb1 in the wattles1 and similar appendages of the head1 a thick vascular network4 ,the beak and the claws are modified skin2 they are true horn material4 ,at the base of the beak there is often formed scales1 which surround the nostrils1 in whole or in part1 and have a naked1 or waxy1 appearance1 which is known as the cera4 ,illustration3 ,,fig4 #gi4--,photomicrograph of the section of skin from the sole of the foot of a hen4 #a1 ,horny stratified squamous epithelium4 a1 ,stratum corneum4 b1 ,stratum lucidum4 c1 ,stratum germinativum4 #b1 ,connective tissue supporting membrane1 pars reticularis4 #c1 ,blood-vessels4 ,the feathers may be considered of two chief kinds1 the quill feathers and the clothing feathers4 ,the most rudimentary of the latter are known as down4 ,a quill feather consists of two principal parts3 the quill1 or calamus1 and the vane1 or vexillum4 ,the quill is continuous with the central shaft1 called the rachis1 the two forming the stem of the feather4 ,projecting outward from the stem on each side are a large number of pointed and very flexible barbs4 ,these barbs are located nearly at right angles to the quill and have extending from them at right angles smaller processes or barbules4 ,these barbules hook together the barbs and give the web its form4 ,in some feathers1 as the hackle1 and in the wing bar feathers of the male of some breeds1 there is a portion of the upper outer edge of the feather not provided with barbules1 which fact gives the feather its characteristic appearance4 ,the down feathers are loose and fluffy4 ,in this kind of feather the shaft is weak1 and the barbs are not provided with barbules4 ,the barbs like the shaft may be considered weak4 ,these feathers give great warmth to the body4 ,there are fiber feathers appearing as hair-like filaments1 and called filo-plum4 ,these are found scattered over the body2 they are particularly abundant in the region of the head and the neck4 ,at each end of the quill is a small opening1 or umbilicus4 ,inside the barrel of the feather there is pulp1 which in young feathers is very vascular2 the vessels entering by the proximal umbilicus are buried1 along with part of the quill1 in a papillated follicle of the skin4 ,from this follicle the feather is developed4 ,at the base of the shaft a secondary rudimentary quill is usually formed1 which may be represented by a mere tuft of down4 ,on the same general principle the smaller feathers are constructed4 ,these cover the body1 the upper parts of the legs1 and the head1 while the larger feathers and quills are confined to the wings and the tail4 ,the longest quill feathers are those arising from the hand1 called the primaries4 ,those arising from the forearm are called the secondaries4 ,those that are developed from the proximal part of the arm are called the tertiaries4 ,the rudimentary pollux carries some feathers which form the alula1 or bastard wing4 ,the scapularies are feathers covering the scapula and the humerus4 ,covering the bases of the larger flight feathers are wing coverts consisting of several rows of small feathers4 ,the quill feathers of the tail are called the rectrices4 ,the rectrices have considerable mobility2 their bases are covered by a row of tail coverts4 ,the pedal digits of the natatores are joined by a membrane1 covered with scaly skin1 which forms the web foot4 ,the feathers in many parts of the body are developed in rows1 there being intervals1 or elongated skin areas1 between these groups of several rows1 which are not provided with feather papill1 but which are covered over by the feathers developed in front of these spaces4 ,the definite feather lines1 or areas1 have been called pteryl4 ,the intervening tracts devoid of feathers are called the apteria4 ,the first outer covering of the bird1 or baby chick1 is a temporary one consisting of fasciculi of long filaments of down4 ,these fasciculi on their first appearance1 are enveloped in a sheath1 which soon becomes ruptured and are entirely cast off by the time the baby chicks are ready to be taken from the nest or the incubator4 ,illustration3 ,,fig4 #hj4--,photomicrograph of the skin of the neck of a ,s4 ,c4 ,white ,leghorn hen4 #a1 ,the skin possessing an outer stratum1 the stratum corneum1 next the stratum lucidum1 next the stratum granulosum and underneath the stratum germinativum4 ,beneath the outer dark band representing the upper skin strata is the pars reticularis of the derma4 #b1 ,papilla showing from inside to outside the hyaline feather wall1 the stratum corneum1 the ,malpighian layer of the follicle1 the corium4 ,inside the feather is noted the pulp-like material4 ,the down fasciculi1 each emerging from its small quill1 are succeeded by the feathers1 which they apparently guide through the skin4 ,feathers do not spring from all parts of the body alike2 especially devoid of feathers are those parts where chafing and friction is greatest1 as under the wings and in the groin4 ,at the end of the quill there is a small opening1 the inferior umbilicus1 into which projects a papilla of the dermis4 ,where the quill emerges from the skin there is another small opening1 the superior umbilicus1 from which springs frequently a small feather called the hyporachis4 ,the shaft1 or rachis1 has a groove extending along that surface which lies next the body4 ,in the newly formed chick the first indication of feathers is the formation of papill1 which is constituted by the upward growth of the dermis1 or the sensitive and vascular parts of the skin4 ,then the skin immediately around the papilla sinks downward1 so that later the papilla is inclosed in a follicle of the skin4 ,the epidermis over the papilla is the same as over the rest of the surface4 ,the horny outer layer of the epidermis forms for the growing feather a protective sheath which is cast off as the feather is formed4 ,the feather proper develops from the underlying germinative layer1 which as the feather develops1 forms a cylinder of cells4 ,the lower part of the cylinder is in touch with the papilla2 this later becomes the quill 7,fig4 #hj1 ,no4 #b74 ,the upper part of the cylinder develops the web portion of the feather4 ,as soon as the feather is fully developed the papilla1 which has projected into the quill and nourished it1 is withdrawn1 and the quill becomes filled with a pithlike material forming septa1 which extend in different directions4 ,once a year1 usually in the late summer or in the fall1 the entire feather coat is changed4 ,this process is called molting4 ,during this time the bird appears in a somewhat depressed condition1 the hen almost always ceases laying4 ,birds also molt in the spring1 to a limited extent4 ,the male at this time takes on the so-called breeding plumage1 which is the most beautiful of the year4 ,it has recently been established by ,rice1 that the young fowl1 in reaching a stage of egg production1 molts five times before the laying period begins4 ,the structure of the skin of fowls is similar to that of the skin of mammals4 ,the skin consists of two layers the outer portion1 or epidermis1 and the inner true skin1 the cutis1 corium1 or dermis4 ,if we study a section of skin from the shank region of a fowl we find the outer portion is differentiated into two distinct regions1 the rete ,malpighii and the stratum corneum4 ,the stratum corneum is the outer horny layer4 ,the cells making up this portion are fusiform1 flattened1 and in regular rows4 ,the nuclei in these layers of cells are not pronouncedly visible1 and the outline of the cells not clear in a section such as used in our ordinary methods of study4 ,the corneum is a compact mass of remnant cells which have lost the appearance and their texture of living cells4 ,it thus becomes modified into scales upon the skin surface4 ,between the stratum corneum and the stratum ,malpighii there is another zone which consists of the cells undergoing a transitional stage from a cubical shape to a more flattened appearance1 and gradually becoming more granular and hyaline4 ,the various parts of the epidermis are in close genetic relationship to one another4 ,the upper layer of epithelium is constantly being desquamated4 ,this casting off is compensated for by a continuous upward pushing of its lower elements4 ,cell proliferation occurs in the basal cells and in adjacent cellular strata of the stratum germinativum1 or stratum ,malpighii1 where the elements are often seen in process of mitosis1 or cell division4 ,the young cells are gradually pushed upward4 ,during their course they assume the general characteristics of the elements composing the layers through which they pass4 ,this process is as follows3 each cell changes first into a cell of the stratum ,malpighii2 then1 when it commences the formation of keratohyalin1 it changes into a cell of the stratum granulosum2 later still1 into a cell of the stratum lucidum2 and finally into an element of the stratum corneum1 where it gradually loses its nucleus1 cornifies1 and at last drops off4 ,the mesodermic portion of the skin consists of loose1 subcutaneous connective tissue containing some fat4 ,the amount of adipose tissue in the subcutaneous layer is subject to great variation2 there are a few places in which there is little or no fat4 ,the upper portion of this layer contains a few elastic fibers1 which interlace and run in all directions4 ,numerous round or oval cells are found in the upper region4 ,the lower and middle portions of the corium are richly supplied with blood-vessels terminating into capillaries1 which penetrate the portions bordering the epidermis4 ,nerves giving off terminal branches also occur4 ,the various colors of the skins of fowls are due to the distribution of various quantities of two colors1 orange-yellow and brownish-black4 ,the yellow pigment is probably carotin and xanthophyll1 two pigments contained in association with the chlorophyll of plants1 which the bird obtains in its feed4 ,these coloring matters were formerly called lipochrome2 but as lipochrome may be any coloring matter of fat1 it is not sufficiently definite4 ,this yellow pigment1 when present1 is diffused through all parts of the cell4 ,when dilute1 it gives a yellow hue2 when concentrated1 orange4 ,it is found in the epidermis and in the fatty masses of and beneath the corium1 and is probably identical with the yellow color of fat in other portions of the body and in the yolk of the egg4 ,a yellow shank1 in a heavily laying hen1 soon loses a part of its pigment2 this is also noted of the coloring matter in other parts of the body4 ,this fact indicates that the coloring matter of the fatty part of the egg yolk is from the same source as that of the fat4 ,the draught of this substance is more than normally and the reserve is being drawn upon4 ,feed rich in zanthophyll and carotin cause intense yellow colored yolks1 and feeds poor in these substances cause the yolks to be a pale yellow4 ,cotton seed meal contains two pigments1 one a yellow crystalline substance and the other a brownish resinous substance4 ,both of these pigments are probably deposited in the egg yolk4 ,the eggs of some hens contain a large quantity giving a light brownish-yellow color to the yolk4 ,the brown or black-brown pigment is carried in microscopic pigment granules1 which may be scattered through the ordinary cells or may be confined to special pigment cells4 ,the former are confined to the epidermis2 the latter may be found in both layers1 but infrequently in the epidermis4 ,when granules are present in the flattened cells of the corium1 they occupy the nuclear region4 ,they lie in short thin lines while those of the under portion of the ,malpighian layer occur in oval groups4 ,where these granules occur in the rete layer1 they cluster around the nuclei4 ,in the colored skin there are dark pigment granules found in the corium and to a less extent in the rete layer4 ,hanau has described a definite cellular body which he found densely packed among the black-brown granules4 ,there is a central body which sends out branches in all directions4 ,in very dark skinned shanks these ramifying strands interlace1 and form a compact network1 which in many cases is so thick as to give the impression of a homogeneous mass4 ,here and there occur round or oval pigmented bodies1 which ,hanau concluded were the star-shaped cells with their pseudopod-like appendages contracted4 ,pigment cells commonly lie around blood-vessels1 clearly indicating their course4 ,they frequently form a compact tube1 but more often are limited to fragments which only partly enclose the vessels4 ,pigment cells occur in several well-defined localities3 in the upper portion of the cutis among the closely interwoven strands of connective tissue2 in the region bordering the blood-vessels2 in proximity to nerves1 in nerve endings and in surrounding fat masses4 ,isolated granules are frequently scattered throughout the lower section of the corium4 ,barrows concludes that the lower bodies of pigment play little or no part in the color of the external shank1 as they lie far below the opaque connective tissue4 ,melanin pigment granules are always contained in the pigment cells4 ,when found in the ,malpighian layer1 the pigment cells are of an oval form4 ,immediately below the epidermis in the shank skin1 extends a space less in width than the row of columnar cells1 which is devoid of pigment4 ,the brown pigment is melanin1 which in large quantities takes on a black hue4 ,white skin does not contain superficial pigment4 ,melanin has been observed in the study of white shank skin1 but it lay at considerable depth or in quantities insufficient to be noticeable4 ,in some breeds of fowls1 as the ,mottled ,houdan1 there are areas in which much melanin is irregularly deposited1 which circumstance gives the leg its mottled appearance4 ,the yellow color is the result of a deposit of the yellow pigment in the fat of the shank4 ,this may be deposited in both layers of the skin1 or in the corium alone4 ,when present it is diffused throughout the entire cell as well as throughout the intercellular substance4 ,in young birds the ,malpighian layer contains much yellow pigment4 ,old hens have only small quantities in the corneum4 ,in breeds with normal yellow shanks old hens that have never laid eggs show a deep orange color in both the dermis and epidermis4 ,in blue shanked birds melanin is present only in the corium4 ,the black pigment is seen through the semi-transparent ,malpighian stratum1 making it appear bluish instead of brown or black4 ,the black shank color results when melanin appears in the epidermis4 ,two forms of black pigment occur in the epidermis3 granules in both layers and pigment cells in the rete ,malpighii4 ,the green shank is produced where there is pigment in the epidermis and numerous melanin pigment cells in the upper corium4 ,it is an optical effect due to melanin lying under the semi-transparent yellow epidermis4 ,there is no melanin in the epidermis4 ,in the beak the corium of the skin is represented by a thin layer located between the periosteum and the stratum ,malpighii4 ,numerous blood-vessels pass into it1 and in the soft horn-like skin1 occur sensory nerve fibers4 ,the nails originate from the epidermis1 of which they are a modification4 ,the nails of the toes are bent downward4 ,they present a convex dorsal surface and are concave ventrally4 ,the dorsal surface consists of a horny plate1 which is set in a nail matrix4 ,the ventral portion merges with the sides of the upper half1 and1 as the lower portion is the softer and wears faster1 the nail has a sharp point and edge4 ,the matrix is formed by a growth of the ,malpighian layer of the cutis4 ,a fold of skin lies over its posterior part4 ,the epidermic cells of the dorsal1 or nail1 part1 and the base of the ventral part grow fast4 ,the outer cell layer gradually becomes horn-like4 ,the spurs are conical with a flat base4 ,the basal part rests upon an enlargement of the shank bone4 ,soft structure is found between the horny spur and the bone4 ,the upper cells1 like those of the nails and of the skin1 are constantly being worn or cast off1 and new cells push up from the lower layers of cells4 ,these newly formed flattened cells soon become cornified4 ,the oldest formation is found at the tip and the youngest at the base4 ,,embryology ,,of ,,the ,,chick ,that a new individual may be brought into existence1 there must be accomplished the union of the male element1 or spermatozoon1 with the female element1 the ovum4 ,this union is called fertilization4 ,in the fowl this fertilization is accomplished at the anterior portion of the oviduct1 after the calyx has ruptured and discharged its yolk1 and before the albumen has been formed around it4 ,the blastoderm is found on the surface of the yolk4 ,one spermatozoon is all that is required2 in fact1 only one can be used in this union4 ,spermatogenesis4--,the spermatozoa are formed by the seminiferous tubules of the testis4 ,from these cells1 called the spermatogonia1 are formed other cells called spermatocytes1 which in turn form the spermatids1 the immediate forerunners of the spermatozoa4 ,during the period of multiplication the spermatogonia divide repeatedly by mitosis4 ,numbers of small cells are thus produced1 each containing in its nucleus the number of chromosomes typical of the somatic cell of that fowl4 ,in the second period the cells become larger and spermatocytes of the first order are formed4 ,then comes the period of maturation1 during which two succeeding divisions rapidly occur4 ,the first division results in the formation of two cells exactly alike4 ,these are spermatocytes of the second order4 ,they differ from the somatic cells in that they contain only one-half the typical number of chromosomes4 ,the second division produces two similar spermatids from one spermatocyte of the second order4 ,therefore four spermatids exactly alike may be formed from one spermatocyte of the first order4 ,from these spermatids the spermatozoa are formed 7,fig4 #ee74 ,the heads of the spermatozoa contain the nuclei derived from the spermatids2 the necks contain the centrosomes2 and the tail1 consisting of three parts is probably formed from the protoplasm4 ,three parts of the tail are as follows3 first1 the pars conjunctionis1 which unites the tail to the neck2 second1 the pars principalis1 which constitutes the main length of the tail2 and1 third1 the pars terminalis1 which consists of an axial filament which transverses the entire tail and is surrounded by a protoplasmic sheath4 ,ogenesis4--,the ovum during its formation passes through three stages4 ,illustration3 ,,fig4 #ha4--,section of ovum in a hen4 #a4 ,nucleolus4 #b4 ,nucleus4 #c4 ,liquor folliculi4 #d4 ,stratum granulosum4 #e4 ,follicular cells4 #f4 ,theca folliculi4 #g4 ,peripheral stroma4 ,the first stage1 that of division1 takes place before the chick is hatched1 and1 according to ,bradley1 comes to an end about the time of hatching4 ,this stage consists of the rapid formation of ova in the female chick4 ,in the second stage1 which begins about the time of hatching1 there is an increase in the size of the units of the ovary1 accompanied by yolk formation4 ,at this time each ovum is in its own follicle 7,fig4 #ha71 and is surrounded by a layer of cuboidal cells and a theca4 ,the theca is formed from the adjacent fibrous stroma4 ,the third stage1 that of maturation1 commences during the development of the yolk and is complete after it has escaped to the oviduct4 ,maturation consists of each cell's dividing into two unequal parts4 ,in each division the cell is split into a small cell known as the polar body1 which is cast off and disappears1 and a larger cell1 which is the ovum proper4 ,in this process half of the original chromosomes are cast off4 ,fertilization4--,the sperm travels rapidly2 experiments have shown eggs to be fertile laid twenty-four hours after service by a male4 ,when the ovum is discharged into the ovarian pocket it is surrounded by spermatozoa4 ,after the male pronucleus has united with the female pronucleus in the single-celled ovum1 there is a cleavage of the cell in the long axis of the egg1 making two cells2 and then a cleavage at right angles1 which progressively continues1 makes the mulberry-like mass4 ,the remaining content of the egg consists of food for the development of the embryo4 ,from this mass of cells before the egg is laid the blastoderm is formed4 ,the cells of the blastoderm are differentiated into two layers4 ,the superficial layer is the ectoderm and the lower layer is the entoderm4 ,in the newly laid egg the blastoderm may be observed4 ,it is about #d millimeters in diameter4 ,it has a transparent central area1 the zona pellucida1 which is located over the subgerminal region4 ,there is a peripheral1 less transparent area called the zona opaca4 ,in the fertile egg1 as soon as it is subjected to the proper temperature1 cell multiplication in the blastoderm begins4 ,the first signs of such change are noted in the pellucid area of the blastoderm where embryonal traces appear in the form of the parallel lines called the plic primitiv1 which diverge to form the cephalic dilatation4 ,at about this time takes place the formation of the myelencephalous columns1 in which the blood lakes expand in the surrounding halones and in the tracts along which pass colorless blood particles4 ,these tracts extend from below the cephalic expansion to the peripheral sinuses1 as the proto-vertebr1 which begin to appear at the sides of the myelon4 ,the red color is acquired by the blood1 and the heart by its movements1 is made more manifest as the punctum saliens4 ,a distinct membrane1 the serous layer1 is formed upon the germ and the blastoderm4 ,the cephalic end of the embryo rises from the surface of the blastoderm1 and then1 curving down1 sinks into it1 forming for itself a kind of hood of the serous layer4 ,this hood gradually extends from the margin of the fossa over the body1 and1 meeting a similar fold formed by the projecting and incurved tail1 closes over the germ on the upper side1 making a circumscribed cavity1 which is the amnion4 ,the progress of differentiation of layers of the blastoderm has1 meantime1 gone on beneath4 ,the serous layer is in part reflected from the vascular and from the mucous layer4 ,the mucous layer is concerned in the formation of the intestinal canal2 and beyond this part1 which is at first an open groove1 the mucous layer expands over the yolk1 which it ultimately incloses1 the margins of the vitellicle so formed contracting and uniting at the side opposite the embryo at a sort of cicatrix1 to which the last part of the abdominal yolk adheres4 ,the vitellicle is richly vascular1 and the surface next to the yolk is augmented by rug4 ,the fowl's egg1 at about the fortieth hour1 shows the buds from which the limbs are developed4 ,a vesicle is seen to protrude near the anal end of the intestine1 which1 rapidly expanding1 spreads over the embryo1 acquiring a close adhesion to the amnion1 but remaining distinct from the vitellicle1 over which it spreads4 ,it finally encloses the albumen and interposes itself between the latter and the lining membrane of the shell4 ,umbilical vessels are associated with this membrane4 ,hunter called this membrane the allantois from its containing urine1 and ,owen states that the sac which surrounds the albumen acts as the chorion or placenta2 for it is most probable that from this surface the albumen is absorbed and the chick supported on its developmental food4 ,the external part of the sac apparently acts as lungs as it comes into contact with the shell of the egg through pores of which there is an exchange of air4 ,oxygen is consumed and carbon dioxide is given off4 ,the blood in the vessels of this membrane is in color more like arterial blood and that in the interior more like venous blood4 ,the embryonic mass of the incubating egg always floats to the top side4 ,as the embryo grows it turns upon its left side1 exhibiting a profile view2 it then indents the yolk1 and finally almost divides it into two parts4 ,the peripheral layers of cells rise from the margin of the germ mass1 and extend and contract toward the opposite pole4 ,this tract of germ substance is the primitive streak4 ,along the median line it next forms a furrow1 which stops short of the ends of the streak4 ,this streak terminates opposite the point from which the germ begins1 and swells into the head4 ,the median furrow expands upon it4 ,the cephalic borders are next united by a thin layer of epithelial cells above the furrow1 converting it into a cavity1 or ventricle4 ,the myelonal furrow is similarly covered by a layer1 uniting the lateral columns4 ,the embryonal trace becomes longer1 narrower1 and bends round the vitellus4 ,a layer of epithelial cells forms a network over the whole dorsal surface of the embryo4 ,oblique stri appear in the broadening germ mass radiating from the primitive streak4 ,these indicate divisional segments4 ,these beginnings of aponeurotic septa probably accompany and support nervous productions from the myelon columns4 ,two transverse constrictions begin to divide the cephalic enlargements into three lobes1 the second and the third of which expand into vesicles4 ,an accumulation of cells at the side of the middle expansion appears to add greatly to its breadth4 ,this forms the basis of the eyes4 ,the differentiation and the confluence of the cell constituents of the primitive streak have led to the formation of a pair of albuminous cords along the sides of the median furrow1 forming the myelon proper4 ,the cells exterior to and above them are converted into muscle and fibrous septa2 and beneath the column is a jelly-filled cylinder1 with a transversely striated sheath1 pointed at both ends1 forming the notocord4 ,its anterior point passes a little in advance of the acoustic vesicle4 ,beneath the notocord and surrounding the blastema is stretched the vegetative1 or mucous1 layer of cells1 in contact with the yolk4 ,both the head and the tail of the now cylindrical embryo are liberated from the surface of the yolk4 ,a fold of the blastema1 reflected from the under part of the head1 sinks like a pouch into the yolk1 and soon includes the rudiment of the heart1 like a bent cord1 which begins to oscillate about the seventh day4 ,from the midline of the inferior surface of the embryo1 or its mucous layer1 two longitudinal plates descend1 diverging into the yolk-substance1 and form the primitive intestinal groove4 ,the ophthalmic vesicle elongates and curves outward until the two ends almost come into contact4 ,between these two ends and beneath the delicate tegumentary layer connecting them the crystalline lens is formed4 ,about the same time1 the otoliths appear in the acoustic vesicles1 which have now acquired a cartilaginous case4 ,the cerebral lobes begin to be formed by a small fold1 rising laterally and overlapping the forepart of the second enlargement1 which has expanded to greater breadth4 ,the olfactory cavities appear as small cutaneous follicles4 ,the two myelonal columns1 expanding between the ear sacs and receding so as to show the notocord beneath1 bend upward and inward1 and unite1 to be continued into the posterior of the optic lobes1 thus commencing the cerebellar bridge across the epencephalic ventricle4 ,the encephalic vacuities have begun to be filled by the granular basis of the cerebellar substance4 ,the intestinal groove begins to be converted into a canal at its two ends4 ,beneath the anterior end1 and behind the heart1 there gradually accumulates the cellular basis of the liver4 ,the commencement of the development of the organ of hearing is by a superficial depression of the cephalic blastema to meet the process from the encephalon1 which forms the acoustic nerve4 ,the lining of the depression becomes1 on closure of the slit1 the proper tunic of the labyrinth4 ,the vesicle of the labyrinth swells into four dilatations1 of which three are ampullar and the fourth cochlear4 ,the ampullar dilatations extend into very slender canals1 at first almost in the same plane1 by which they are brought into mutual communication4 ,as the canals expand and elongate1 they assume their characteristic relative positions as external1 superior1 and posterior1 the posterior end of the external canal being extended beneath the posterior canal4 ,the cochlear dilatation curves as it elongates4 ,an inner layer becomes distinct from the common membrane and forms the acoustic lamina4 ,as in the development of the ear1 so in the development of the eye1 the production of the nerve process from the cerebral center is the first step2 the infolding of the superficial blastema to meet the nerve is the next4 ,the so-called cutaneous follicle becomes a circumscribed sac or vesicle1 in which the changes and the development next proceed1 converting the vesicle into an acoustic labyrinth or into an eyeball4 ,in each case neural elements of two vertebr become modified to lodge and to protect the sense organs1 forming respectively the recess called otocrane and that called the orbit4 ,the one is located between the occipital and the parietal vertebr1 and the other between the frontal and the nasal vertebr4 ,the part of the outer blastemal layer of the head which sinks to meet the process from the mesencephalic dilatation1 rapidly changes its follicular into a vesicular state4 ,the vesicle thus formed elongates1 bending around the cell mass in which the crystalline lens is formed1 and the meeting of the two ends results in forming the choroid fissure at the lower part of the eyeball4 ,the mesencephalic process1 or optic nerve1 expands at the posterior of the circular sac1 and1 in the course of mutation into eyeball1 lines its posterior part with a layer which becomes the retina4 ,the transparent layer covering the forepart of that sac and the inclosed lens is formed into the cornea4 ,other layers of the sac are formed into the choroid1 the ciliary processes1 the iris1 and the pecten4 ,of the appendages of the eye the membrana nictitans is the first to develop4 ,then develop the lower lid and1 last1 the upper lid4 ,after the development of the essential organs of sense1 the skin is developed4 ,modifications of the skin form the outer ear and the eyelids4 ,then are formed the maxillary arch1 the hyoidean arch1 and the scapular arch4 ,the vessels which return the blood from the vitellicle are the transverse and the longitudinal vitelline veins4 ,the first are so called because these trunks pass to the embryo at right angles to its axis4 ,they are the largest returning canals4 ,the longitudinal veins extend parallel with the axis of the embryo2 they are of smaller size4 ,the right anterior longitudinal vein becomes the right precaval and receives the remains of the right transverse vitelline vein1 as the right vena azygos4 ,the left anterior longitudinal vitelline vein is also persistent as the left precaval1 and enters in the mature bird1 as in the embryo1 at the posterior or the lower part of the auricle4 ,the left transverse vitelline vein is also subsequently reduced1 by receiving only the vertebral veins of that side1 to the condition of a so-called azygos vein4 ,the main trunk of the post-caval is the result of the returning vessels from the abdominal viscera and the posterior limbs at a later stage of development4 ,there is but one principal posterior longitudinal vitelline vein1 and this anastomoses with the left transverse vein as it enters the embryo4 ,the auricle1 which1 by its dilatation of the left side1 appears to be double1 receives the venous blood at its right division4 ,the left one1 subsequently receives the veins from the lungs1 is ultimately separated from the left precaval and the right auricle to which that vein is conducted and restricted4 ,the ventricular part of the heart1 at the second day of incubation1 is in the form of a bent tube1 curving from behind downward1 forward1 to the right and upward1 continuing insensibly into the part representing the aortic bulb1 in which the septum first appears1 and ultimately dividing the ventricle into two4 ,at this stage the piers of the maxillary arch appear as buds from beneath the eyeballs4 ,the naso-premaxillary process is above their interspace4 ,the piers of the mandibular arch and those of the hyoidean arch follow in close succession4 ,the blastemal base of the scapular arch projects slightly at the sides of the fovea cardiaca2 the piers1 now separate1 ultimately meet in front of the heart1 and accompany it in its retrograde course4 ,the mesencephalon is the largest of the segments of the brain which are connected with the eyeballs4 ,when the heart has assumed its form as such1 distinct from the great trunks rising from it1 the two arteries from the base of the ventricles appear4 ,the artery to the right bifurcates1 one division supplying the head and the wings1 the other winding over the right bronchus4 ,that to the left also bifurcates4 ,its left division arching over the left bronchus and anastomosing with the right arch a little below and behind the apex of the heart4 ,its right division arches over the back of the heart1 bending to the right and anastomosing with the right aortic arch just above the outer ductus arteriosus4 ,each of these divisions of the left primary arterial trunks sends off a branch to its corresponding lung4 ,as the lung expands1 and especially at the beginning of the act of expansion toward the close of the period of incubation1 the blood is diverted into the pulmonary vessels1 and the channels below them shrink and disappear4 ,the left primary artery is retained as the trunk of the pulmonaries1 and1 through the changes in the interior of the ventricle1 this artery comes to discharge exclusively the ventricle corresponding to the right in mammals4 ,the retained aorta rises from the left ventricle4 ,the air-sacs begin at the lower point of the lung1 appearing like small hydatids1 and extend further and further into the abdomen1 in front of the kidneys4 ,they are at first full of fluid4 ,soon after the development of the abdominal air-sacs others are developed4 ,the lungs are at first free1 but afterward begin to be attached to the ribs and to the spine4 ,in the female embryo we first observe two oviducts1 one on each side of the basis1 or stroma of the ovarium1 which appears in a relation to the primordial kidneys similar to that of the testes in the male4 ,at the period when the permanent kidneys have sent their ureters to the cloaca1 the oviducts have been developed as prolongations from that part1 and1 up to a certain point of development1 they are of equal size and length4 ,subsequently the left oviduct alone continues to grow2 the right remaining stationary or shrivels2 occasionally it may be discerned as a rudimentary in the mature bird1 but usually all trace of it has disappeared before hatching4 ,the left oviduct expands above or at its free end into the infundibular orifice1 where its parietes are very thin4 ,as it descends1 these increase in thickness1 and the efferent tube gradually acquires the texture and form of an intestine4 ,it is attached and supported by a duplicature of the peritoneum4 ,illustration3 ,,fig4 #hb4--;,embryological studies4 ,a4 #a1 ,the chorion and allantois4 #b1 ,the allantoic cavity4 #c1 ,the amnion4 #d1 ,the yolk sac4 #e1 ,a small quantity of remaining albumin4 ,b4 ,brain tube of a chick #be hours old showing partly closed brain tube with eleven folds of neuromeres4 ,c4 ,the development of the alimentary tract4 #a1 ,trachea4 #b1 ,lung4 #c1 ,esophagus4 #d1 ,stomach4 #e1 ,pancreas4 #f1 ,bile duct4 #g1 ,v-shaped loop of midgut4 #h1 ,cloaca4 #i1 ,vitello-intestinal duct4 ,d4 #a to #f inclusive1 same as ,c4 #g1 ,cca4 #h1 ,cloaca4 ,e4 ,kidneys1 ,wolffian bodies1 and testes of an embryo chick4 #a1 ,the adrenals4 #b1 ,the genital4 #c1 ,primitive oviduct4 #d1 ,permanent kidney4 #e1 ,ureters4 #f1 ,duct of primitive kidney which conducts the excretion into the cloaca4 ,f4 ,a transverse section of a chicks' head #dh hours of incubation4 #a1 ,forebrain4 #b1 ,pigmented layer of retina4 #c1 ,ectoderm4 #d1 ,nervous part of retina4 #e1 ,optic stalk4 #f1 ,invagination of ectoderm to form the lens rudiment4 ,at first1 the right and the left ovaria are similar in size1 but the symmetry is soon disturbed by concentration of development in the left ovary4 ,the right ovary remains stationary and ultimately1 in most birds1 completely disappears by the time the chick is ready to emerge from the shell4 ,three fetal membranes are developed1 the chorion1 the amnion1 and the allantois4 ,there is also developed the yolk sac 7,figs4 #hb and #hc74 ,the amnion is connected to the body wall at the umbilicus4 ,the amniotic fluid is found in this sac4 ,the chorion is at first surrounded by the albumen1 but as the albumen is absorbed the chorion comes in contact with the inner shell membrane4 ,it is probable that the chorion consists of ectoderm on the outside and of mesoblast on the inside4 ,the amnion1 on the other hand1 is formed of mesoblast on the outside and ectoderm on the inner1 or embryonal1 side4 ,the allantois springs from the embryo soon after the fourth day1 and develops from the ventral wall of the primitive gut4 ,by some embryologists1 the yolk sac is included in the embryonic membranes4 ,it commences as the splanchno-pleure surrounding the mass of yolk4 ,it becomes smaller as the yolk is absorbed4 ,at first its outline is round but later its walls become folded in4 ,the yolk is dissolved and absorbed by the entodermic lining of the sac1 and is carried to the embryo by veins called the vitelline veins 7,fig4 #hc1 ,no4 ,b1 #d71 which ramify on the walls of the sac4 ,some time after the fourteenth day1 the chick assumes a position lengthwise within the egg shell so that the head is near the broad end of the egg4 ,the head is bent upon the chest and the beak is usually tucked under the wing4 ,later the head assumes a position1 by a double curve of the neck1 so that the beak is in contact with the air cell4 ,about the fifteenth day1 the coils of intestine1 which heretofore have been outside the abdominal cavity1 are withdrawn into the abdominal cavity1 as is also the abdominal yolk sac4 ,as the chick pips out of the shell1 the umbilicus becomes occluded4 ,the outer upper part of the tip of the beak is provided with a short1 stout1 spike-like arrangement1 called the egg tooth4 ,on the twentieth day this part of the beak is forced against the wall of the egg and gradually breaks through the egg shell4 ,the breathing by the lungs commences some time before hatching2 this is evidenced by the chick within the shell giving chirping sounds4 ,illustration3 ,,fig4 #hc4 ,a4 ,longitudinal section of chick1 #d days incubation4 #a1 ,cephalic fold4 #b1 ,caudal fold4 #c1 ,true amniotic cavity4 #d1 ,epiblast4 #e1 ,somatic mesoblast4 #f1 ,visceral mesoblast4 #g1 ,hypoblast4 #h1 ,future anua still closed4 #i4 ,the allantoic vessicle4 #aj1 ,the mesentery4 #aa1 ,intestine4 #ab and #ac1 ,yolk sac4 #ad1 ,cavity of true amnion4 #ae1 ,the mouth4 #af1 ,pleuroperitoneal cavity4 #ag1 ,fore gut4 ,b4 ,membranes of the chick at the third day of incubation4 #a1 ,membrane surrounding albumin4 #b1 ,amnion4 #c1 ,allantois4 #d1 ,vitellicle4 ,c4 ,the fore part of an embryo chick at the second day4 #a1 ,mesencephalon4 #b1 ,the eye4 #c1 ,olfactory organ4 #d1 ,mandibular arch4 #e1 ,maxillary arch4 #f1 ,maxillary arch4 #g1 ,hyoidean arch4 #h1 ,scapular arch4 #i1 ,depression organ of hearing4 #aa1 ,process from encephalon for union with nerve of hearing4 ,d4 ,primitive blood-vessels at second day of incubation 7,owen74 #a1 ,mesocephalon4 #b1 ,the right anterior longitudinal vein4 #c1 ,the eye4 #d1 ,the mandibular arch4 #e1 ,the hyoidean arch4 #f1 ,scapular arch4 #g1 ,the same4 #h1 ,the ventricular portion of the heart4 #i1 ,the right transverse vitelline vein4 #aj1 ,posterior longitudinal vitelline vein4 #aa1 ,vertebral vein4 #ab1 ,tributaries of same4 #ad1 ,the auricle4 #af1 ,aortic bulb4 ,e41 ,a transverse section of chick embryo1 #bi hours incubation4 #a1 ,neural canal4 #b1 ,neural crest4 #c1 ,somatopleure4 #d1 ,splanchnopleure4 #e1 ,omphalomesenteric vein4 #f1 ,aorta4 #g1 ,notocord4 #h1 ,pleuroperitoneal cavity4 ,f4 ,chick embryo at the ninth day of incubation4 #a1 ,allantois4 #b1 ,amnion4 #c1 ,air cell at large end of the egg4 #d1 ,egg shell4 #e1 ,outer shell membrane4 #f1 ,inner shell membrane4 #g1 ,yolk sac4 #h1 ,albumin 7,bradley74 ,the circulation of the blood is somewhat like the circulation in the fetus of quadrupeds4 ,the primitive tubular heart 7,fig4 #hc1 ,no4 ,d1 #h7 is bent in ,s-shape2 the two ends are connected with blood-vessels2 and later1 by the development of the septa1 the cavities of the adult heart are defined4 ,the foramen ovale is found in the median septum4 ,this opening brings the right and the left side into communication4 ,the septa between the cavities of the heart are completed by the end of the sixth day4 ,the two vitelline1 or omphalo-mesenteric1 veins carry the blood containing the nutrients from the yolk sac to the liver1 where it is mixed with the blood drained from the intestines by the portal vein1 and this blood is finally carried by the posterior vena cava into the right auricle of the heart4 ,from here it passes through the foramen ovale to the left auricle2 from the left auricle it enters the left ventricle1 from which it is forced into the aorta1 and then out into the systemic circulation4 ,practically all1 if not all1 of the blood of the pulmonary artery is sent into the aorta through a connection with this vessel called the ductus arteriosus4 ,down appears about the thirteenth day of incubation4 ,there are two kinds of down on the chick1 one long1 which comes first1 about two or three days before hatching2 a second1 or fine1 down forms at the roots of the other4 ,as the embryo develops the air cell1 at the large end of the egg which is developed between the two shell membranes1 or membran putamin1 gradually enlarges4 ,,outline ,,for ,,laboratory ,,study ,,of ,,the ,,chick ,the objects of laboratory study of the embryos are as follows3 #a4 ,to study the living embryo4 #b4 ,to study the entire embryo3 ,with the dissecting microscope1 as an opaque object4 ,with the compound microscope after killing1 hardening1 clarifying1 and mounting4 #c4 ,to study embryos by dissection1 in later stages4 #d4 ,to study the serial sections with the compound microscope4 ,,the ,,living ,,embryo ,the egg is opened under warm physiological salt solution3 #j4h per cent4 sodium chlorid in distilled water heated to a temperature of #ch;,c4 ,gradually pick away the shell at the large end4 ,note that there are two membranes and an air cell4 ,strip off the membranes4 ,when sufficient shell and membranes have been removed from the large end1 invert the open end of the egg in the salt solution and allow the contents to flow out4 ,care must be taken not to break the yolk4 ,the embryo1 or blastoderm1 lies upon the surface of the yolk1 which is usually turned with this body uppermost4 ,separate the blastoderm by cutting around the outside of the area vasculosa4 ,in doing this a small pair of slightly curved scissors is needed4 ,after the embryo1 or blastoderm1 has been separated1 gently float it into a watch crystal with the flat bottom submerged in the salt solution4 ,the watch crystal with its contents may now be gently lifted out4 ,next remove the vitelline membrane4 ,the vitelline membrane is the delicate transparent membrane covering the blastoderm1 ,the embryo is now ready for study4 ,,the ,,preparation ,,for ,,study ,,of ,,entire ,,embryos ,,and ,,sections ,the following processes may be used in killing embryos up to four days1 or ninety-six hours1 of age4 ,after removing the embryo as described above1 spread the blastoderm out in the watch crystal and pipette off the salt solution4 ,allow it to stand till the edge of the tissue begin slightly to adhere4 ,then slowly add the killing fluid by aid of a pipette1 dropping it on the center of the embryo4 ,the pipette must be held low or the mechanical interference will dislocate the parts4 ,older embryos are submerged with their membranes intact into the killing fluid4 ,the quantity of fluid should be several times the bulk of the specimen4 ,kleinenberg's picrosulphuric acid may be used as a killing fluid4 ,this fluid is a saturated solution of picric acid plus #b per cent4 sulphuric acid1 to which is added twice its volume of water4 ,chick embryos from one to two days old should be left in this fluid from one and one-half to six hours4 ,embryos from two to four days old two and one-half to six hours4 ,remove the specimen from the killing fluid1 and place it in #gj per cent4 alcohol4 ,change the alcohol every twenty-four hours until the color ceases to come out of the embryo4 ,preserve in #hj per cent4 alcohol4 ,if the specimen is to be mounted whole1 transfer it from #hj per cent41 then to #ej per cent41 then to #ce per cent41 and1 finally to water4 ,small embryos should remain in each fluid thirty minutes and large ones sixty minutes4 ,the following method may be used for staining embryos3 ,dilute ,delafield's hematoxylin with four times its volume of water4 ,to every #f cubic centimeters of this diluted hematoxylin1 add one drop of ,kleinenberg's undiluted picrosulphuric acid1 and leave specimen in the fluid thus prepared until it is stained through4 ,this will require from one to three hours4 ,now pass up through the series of alcohols to #gj per cent4 ,next extract the excessive stain with #a per cent4 hydrochloric acid in #gj per cent4 alcohol4 ,wash repeatedly with #gj per cent4 alcohol to free from the acid2 then transfer the specimen to #hj per cent4 alcohol and leave in this for several hours for complete removal of the acid2 then transfer to #ie per cent4 alcohol for thirty minutes4 ,allow the specimen to remain in absolute alcohol for one hour4 ,introduce a layer of oil of cloves or xylol beneath the alcohol4 ,this may be done by gradually allowing the fluid to run down the side of the bottle4 ,after the embryos have sunk into the oil and begun to appear transparent1 remove the fluid and add fresh oil4 ,after the specimen is sufficiently transparent1 mount in balsam1 supporting the cover slip so that it will not rest on the embryo4 ,in staining for section1 place the embryo in borax carmine from the #ej per cent4 alcohol and leave twelve hours4 ,then wash in #ej per cent4 alcohol2 after which transfer to #gj per cent4 alcohol for six hours4 ,clarify in oil of cedar or oil of cloves1 and place in melted paraffin for two hours4 ,imbed in paraffin1 and section4 ,embryos may be hardened1 imbedded1 and sectioned after the usual methods1 using either paraffin or celloidin1 and the sections stained with hematoxylin and eosin after sectioning4 ,,points ,,to ,,be ,,observed ,,in ,,the ,,study #a4 ,,the ,,embryo ,,twenty-,,nine ,,to ,,thirty-,,four ,,hours ,,old ,,with ,,from ,,ten ,,to ,,fourteen ,,somites4 ,a study of the egg4 ,in opening the egg1 observe that the shell membranes are double4 ,observe that the shell is porous4 ,note the air cell at the large end of the egg and note that the space or cell lies between the outer and the inner shell membrane4 ,after the egg contents have dropped into the salt solution1 note extending from the ends of the yolk the twisted denser cords of albumen4 ,these are the chalaz1 which act as stays to the yolk4 ,note that the yolk is surrounded by a delicate membrane4 ,this is the vitelline membrane4 ,the yolk is the true ovum and serves as food for the developing embryo4 ,a study of the living embryo4 ,note the amount of yolk that is covered by the blastoderm4 ,note the slipper-shaped1 transparent center of the blastoderm4 ,this is the area pellucida4 ,in the center of this there is a narrow white streak4 ,the area opaca is the area lying external to the area pellucida4 ,in this there is the area vasculosa4 ,a study of the embryo entire1 including the vascular area4 ,the blood islands show as irregular deeply stained masses in the vascular area4 ,at this stage they are inclosed in wide anastomosing tubes1 the extra-embryonic blood-vessels1 which open peripherally into the bounding sinus terminalis4 ,the following structures may be identified3 ,the neural tube forming the axis of the embryo4 ,in the anterior region may be noted the forebrain1 the optic vesicles1 the midbrain4 ,the hindbrain is subdivided into the neuromeres4 ,the cord1 or myelon1 of the neural tube back of the hindbrain is closed in front but is open behind4 ,the head projects above the blastoderm4 ,the fold which unites the ventral surface of the head with the blastoderm is called the head fold4 ,the diverging folds of the myelon encloses the primitive streak4 ,on each side of the neural tube are the mesoblastic somites4 ,the series is continued behind by the undivided segmental plate4 ,the heart is beneath the hindbrain4 ,the portion of the body cavity in which it lies1 is bounded in front by the head fold and behind by the diverging limbs of the splanchno-pleure4 ,its posterior or venous end receives the vitelline veins from the vascular area4 ,the anterior or arterial end is prolonged into the ventral aorta4 ,note that the axis is somewhat bent4 ,the head fold of the amnion is noted to extend over the anterior end of the head4 ,a study of the transverse sections4 ,the sections about #bj micro-millimeters thick should be cut serially1 and so mounted4 ,knowing how many micro-millimeters the embryo is in length will enable one to make a diagram of the fetal structure in the study of the series of transverse sections4 ,the sections should be drawn in the order studied so as to obtain relative structural ideas4 ,with the microscope study the following regions3 #a4 ,optic vesicle4 #b4 ,midbrain4 #c4 ,posterior half of the heart4 #d4 ,myelon in the closed region4 #e4 ,myelon in the open region4 #f4 ,through the primitive streak4 #b4 ,,the ,,embryo ,,twenty ,,to ,,twenty-,,four ,,hours ,,old ,,with ,,from ,,two ,,to ,,six ,,somites4 ,compare the parts in this embryo with those of the embryos from twenty-nine to thirty-four hours old4 ,note and describe the relations of the embryo1 the area pellucida1 and the area opaca4 ,note how much of the yolk the blastoderm covers4 ,in studying the entire embryos1 note the condition of the medullary plate4 ,observe if the tube is formed in any part2 how far back the head plate extends1 if the heart can be seen2 and if the primitive streak is longer or shorter than in #a4 ,study relations of structures and make drawings through the point of divergence of the walls of the fore gut2 also through the somatic region1 and through the primitive streak4 ,study all parts1 as the head fold1 the heart1 and the fore gut4 #c4 ,,the ,,embryo ,,forty-,,four ,,to ,,forty-,,eight ,,hours ,,old ,,with ,,twenty-,,four ,,to ,,twenty-,,nine ,,somites4 ,remove the embryo with the entire area1 and preserve it4 ,note and carefully describe the changes visible to the naked eye since the thirty-fourth hour4 ,in making a study of the entire embryo we note there has been a rapid growth of the dorsal surface of the head1 which has become more bent4 ,this bend1 in the region of the midbrain is called the cephalic flexure4 ,the forebrain and part of the midbrain form almost a right angle with the rest of the head4 ,the head is compressed laterally and free from the blastoderm4 ,the dorsal side of the trunk is turned up1 and there is a twisting of the axis of the embryo just back of the heart4 ,the tail fold begins at about this time and may or may not be visible4 ,the optic vesicles are relatively smaller in relation to the brain than in #a4 ,note the part of the forebrain to which they are attached4 ,observe the inner and outer layers of the retina1 the lens1 the choroid fissure1 and the cavity of the vitreous humor4 ,note the auditory vesicles and whether or not they are closed sacs4 ,note that the heart has grown in length and has become doubled on itself4 ,the two ends are fixed4 ,note the relation of the heart to the afferent and efferent blood-vessels4 ,note that two1 and possibly three1 visceral pounches are visible4 ,note whether or not they are ventral to the midbrain4 ,the first1 the hyomandibular pouch1 is bounded in front by the first visceral1 or mandibular1 and behind by the second visceral1 arch4 ,the second pouch is bound in front by the hyoid1 and behind by the third visceral arch4 ,the third pouch is bounded in front by the third visceral arch1 and behind by the fourth4 ,note the number of mesoblastic somites and the condition of the mesoblastic segmental plates4 ,note how far back the foregut is closed4 ,locate the head fold of the amnion1 and note how far back it is closed4 ,note changes that have taken place in the vascular area4 ,in studying the sections it will be found that a section cut transversely to the trunk will pass horizontally through the forebrain and through the midbrain4 ,study a section through the trunk a short distance behind the heart4 ,observe the elevation of the axis of the body4 ,note the way in which the lateral folds1 or the lateral limiting sulci1 in the somatopleure1 delimit the embryonic from the extra-embryonic area4 ,note the appearance of the mesenchyme1 the approximation of the two dorsal aort1 the appearance of the amniotic folds4 ,observe in the mesoderm the posterior cardiac veins1 and the myotomes1 or muscle plates4 ,the sclerotome is made up of the mass of mesenchyme between the myotome1 on the one hand1 and the neural tube and the notochord1 on the other4 ,note the folding of the splanchno-pleure1 and note if there is present the ,wolffian duct1 or the nephrotome4 ,study sections through the optic vesicles4 ,note if there is the beginning of the lens4 ,do you note the diverticula of the pharynx8 ,can you identify the closed amnion and the chorion8 ,study sections through the auditory pit4 ,note fusion of the gill pouches with the ectoderm4 ,note the blood-vessels4 ,study sections through the region of the heart1 through the roots of the vitelline veins1 and through the primitive streak1 if it is still present4 ,for this study it will appear that the anterior end has developed in advance of the posterior end4 ,the tail fold has probably just begun4 ,write a description of the pharynx1 and of the circulation at this stage4 #d4 ,,the ,,embryo ,,sixty-,,eight ,,to ,,seventy-,,two ,,hours ,,old ,,with ,,cervical ,,flexures ,,formed4 ,in a study of the living embryo note the changes visible to the naked eye since forty-eight hours old4 ,note the difference in the blood-vessels of the vascular area4 ,name the arteries and veins4 ,note the beating of the heart4 ,in a study of the entire mount note that a second1 the cervical flexure1 has appeared in the head4 ,note that the tail fold is well formed4 ,note the position of the embryo on the blastoderm4 ,determine if the amnion is completely closed4 ,note the olfactory pits on the ventral surface of the head1 a short distance in front of the optic stalks4 ,note the telencephalon1 a rudiment of the cerebral hemispheres and an extension of the primary forebrain4 ,it is bilobed anteriorly4 ,the optic stalks are attached to the floor near the anterior end of the thalamencephalon4 ,note the infundibular region1 which is the depressed region behind the optic stalks4 ,in the roof of the thalamencephalon there is a short diverticulum1 the epiphysis4 ,the mesencephalon1 or midbrain1 forms the apex of the cranial flexure1 and is united to the hindbrain by a narrow isthmus4 ,the metencephalon1 or rudimentary cerebellum1 appears as a thick portion on the most anterior division of the hindbrain4 ,the rest of the hindbrain is provided with a transparent roof and constitutes the myelencephalon1 or the rudimentary medulla oblongata4 ,observe the inner and the outer wall of the optic cup1 the lens1 the choroid fissure1 and the posterior1 or vitreous1 chamber4 ,note the form of the otocyst1 or auditory sac4 ,note above which visceral arch it lies4 ,note the number of visceral clefts4 ,the visceral arches are formed by the thickening of the walls of the bounding clefts4 ,the visceral arches are as follows3 the first is the mandibular1 or hyomandibular1 arch1 which is in front of the first cleft4 ,from this there is developed the lower jaw4 ,note if there is a maxillary process arising from the dorsal angle of the arch4 ,the second arch is the hyoid arch1 which is located behind the first cleft4 ,then follow in order the third1 the fourth1 and the fifth visceral arches4 ,note above the mandibular arch the rudimentary trigeminal ganglion1 and above the hyoid arch the rudimentary acoustico-facialis4 ,the latter is in contact with the anterior walls of the auditory sac4 ,the rudimentary glosso-pharyngeal ganglion is noted above the third visceral arch4 ,the vagus1 or pneumogastric1 ganglion is located above the fourth and the fifth4 ,note the form and the position of the heart4 ,note the anterior and the posterior limb rudiment in the trunk4 ,in a study of the sections it is found that cuts transverse to the trunk pass about horizontally through the forebrain4 ,at this age the following sections of the embryo should be studied3 ,first1 through the hindbrain1 at which level will be noted the auditory sacs1 the neuromeres1 the trigeminal1 the acoustico-facialis1 and the glosso-pharyngeal and the vagus ganglion4 ,second1 through the upper part of the pharynx1 at which level will be observed the midbrain1 the hindbrain1 the visceral pouches1 the nerves1 and the blood-vessels4 ,third1 through the choroid fissure of the optic cups4 ,note the parts of the eye1 and1 on the other side of the section1 the heart4 ,fourth1 a study of a section through the olfactory pits4 ,fifth1 a study of a section through the pancreatic and the hepatic diverticula4 ,sixth1 a study at the beginning of the allantois through the hind-gut4 ,at this age it is of interest to study the systems of organs4 ,observe the manner in which the splanchno-pleure folds to form the walls of the intestine4 ,note the commencement of the mesentery4 ,note that the foremost part of the alimentary tract is formed from the stomodeal invagination of the ectoderm4 ,the hypophysis is formed from a dorsal outgrowth of this4 ,note its relation to the brain4 ,the following structures are formed from outgrowths of the ectoderm at this stage3 ,first1 the visceral pouches4 ,second1 the median rudiment of the thyroid4 ,this is an outgrowth from the pharynx between the two hyoid arches4 ,third1 the rudimentary lungs1 which develop in a pair from a median ventral diverticulum of the alimentary tract1 just behind the last visceral pouch4 ,the esophagus is just posterior to this4 ,the esophagus1 very short at this stage1 is continuous with a slightly wider part that develops into the stomach4 ,fourth1 the first liver diverticulum1 and1 at a short distance posterior to this1 the second liver diverticulum4 ,fifth1 the pancreas is at a point where the intestine opens ventrally4 ,it first appears as a slight thickening of the dorsal angle of the intestine4 ,sixth1 the ventral wall of the hind-gut forms a wide evagination4 ,seventh1 the beginning of the allantois4 ,after the whole series of transverse sections have been studied and drawn1 construct a longitudinal section of the fetus1 including a reconstruction of the alimentary tract4 ,at this stage the heart is a simple tube4 ,the following divisions are distinctly visible3 the auricular portion1 the ventricular portion1 the sinus venosus1 and the bulbus arteriosus4 ,the union of the two ductus ,cuvieri and the ductus venosus form the sinus venosus4 ,the two ductus ,cuvieri are formed by the union of the anterior and the posterior cardinal veins4 ,the ductus venosus is formed by the union of the small right and the large left vitelline vein4 ,these latter veins return the blood from the yolk sac4 ,the sinus venosus empties into the single auricle above which it is located4 ,the single auricle is later divided into two chambers1 the right and the left auricle4 ,at this stage it is widest in the lateral direction4 ,the auricle empties directly into the ventricle4 ,the ventricle lies ventrally and behind the auricle4 ,this location is due to the bending of the heart at this stage of development4 ,its hindmost portion forms the future apex of the heart4 ,if the series of sections be studied from the posterior forward1 the ventricle will be first to appear in the sections4 ,just beneath the auricular portion of the heart there is the bulbus arteriosus4 ,the bulbus arteriosus soon divides into a number of aortic arches4 ,there is an ascending pair in each of the visceral arches4 ,the dorsal aorta is formed by the union of the aortic arches above the visceral arches4 ,the aortic arches are first continued a short distance forward as the carotid arteries4 ,the dorsal1 or posterior1 aorta passes backward under the notochord4 ,the dorsal aorta divides into two parallel aort which give off on each side the vitelline arteries4 ,note other branches of this aorta4 ,the veins at this stage consist of the anterior and posterior cardinal1 the ductus venosus1 the ductus ,cuvieri1 and the vitelline veins4 ,make drawing of the circulatory system after a completion of the study of the series of sections4 ,make a study of the nervous system according to hints already given4 ,the dorsal and the ventral roots of the spinal nerves are given off separately1 and secondarily unite4 ,from the neuroblasts of the cord there are at regular intervals outgrowths representing the ventral roots4 ,from the neural crest there develop segmental collections of neuroblasts which form the spinal ganglia1 from which the dorsal spinal nerve roots develop4 ,in fact this developmental stage can be observed in embryos only forty-eight hours old1 first appearing as a line of cells springing on each side from the angle between the neural canal tube and the external epiblast4 ,in the section from the embryo seventy-two hours old there are observed the rudiments of the development of these spinal nerves4 ,four primary ganglia develop in the neural crest of the head4 ,these ganglia are as follows3 the acoustico-facialis ganglia1 which is located over the hyoid arch2 the ganglia of the trigeminus1 which is located over the mandibular arch2 the ganglia of the glosso-pharyngeus1 which is located over the third visceral arch2 and the ganglia of the vagus1 which is located over the third and the fourth visceral cleft4 ,in this stage of development the trigeminal and the acoustico-facialis are clearly visible4 ,on each side and dorsal to the aorta is noted the ,wolffian body1 or mesonephros4 ,the ,wolffian body 7,fig4 #hb1 ,e7 consists of a series of tubules imbedded in the mesenchyme4 ,the openings into the ,wolffian duct lie just beneath the cardinal vein4 ,in a study of the ,wolffian duct determine just how far anteriorly and how far posteriorly it extends4 ,note whether it empties into the cloaca4 ,each tube beginning in a blind extremity is later dilated4 ,it has a thin wall1 and is situated near the median portion of the ,wolffian body4 ,the tubule proper passing transversely1 opens into the duct4 ,the upper wall of the thin walled part is invaginated by a mass of mesenchyme that receives a small vessel from the dorsal aorta4 ,the ,malpighian corpuscle1 consisting of a glomerule and ,bowman's capsule1 is thus established4 ,in the study of the four days old chick note the further development of these parts4 ,in a study of a chick four days1 or ninety-six hours old1 note to what extent the yolk is covered by the blastoderm4 ,it will be noted that the embryo lies in the extra-embryonic cavity4 ,this cavity is bounded above by the chorion and below by the splanchno-pleure4 ,in removing the amnion from the embryo1 note the relation to the somatic umbilicus4 ,note the relation of the splanchnic umbilicus to the splanchno-pleure4 ,what relation has the allantois to the above8 ,in examining the head1 locate the cerebral hemispheres1 and note their development4 ,locate the pineal gland4 ,note changes in the olfactory pit and the eye4 ,locate the lens and the choroid fissure4 ,note that the maxillary process of the mandibular arch lies beneath the eye and behind the olfactory pits4 ,note the otocyst and the relations of the other arches to the above structures4 ,in a study of the trunk1 note the tail1 the allantois1 ,wolffian ridges1 the heart1 and the condition and the position of the rudimentary limbs4 ,make drawing of embryo from the side view4 ,carefully cut off the head immediately behind the last visceral arch1 and study and draw the structures observed on the ventral side4 ,note the maxillary processes1 the mandibular and the hyoid arch1 the nasal pits1 and the fronto-nasal process1 which is just beginning its development4 ,in a study of transverse sections observe from your drawing at what level the section is made4 ,study and draw a section made through the region of the anterior limbs4 ,note the spinal ganglion1 the muscle plate1 or myotome1 the condensation of mesenchyme around the notochord1 the pancreas1 the liver1 and the intestine2 and note the distribution of the mesenchyme4 ,note the ventral roots of the spinal nerves1 and the neuroblasts in the spinal cord4 ,in sectioning the embryo from before backward1 the first sections will pass horizontally through the hindbrain and the midbrain region4 ,note the parts1 including the auditory vesicle4 ,in the first series of sections also locate the ganglia of the pneumogastric1 or vagus1 the acoustico-facialis1 the trigeminus1 and the glosso-pharyngeal nerves4 ,note the notochord and the cardinal veins4 ,after the disappearance of the ear1 we observe the midbrain1 which1 is located at one end of the section1 and the cord at the other end4 ,the region between lies just above the pharynx4 ,in the following series study the visceral arches4 ,note the third pair of cranial1 or motor ocular1 nerves4 ,this latter nerve springs from the floor of the midbrain4 ,from the ventral prolongation of the floor of the thalamencephalon there arises the infundibulum4 ,the hypophysis is located just beneath the infundibulum4 ,at this stage the hypophysis appears as a tube to empty into the mouth4 ,this is an ingrowth of the oral epithelium4 ,in a study of a section through the center of the eye we should observe the lens and optic stalk4 ,this is in the region of the optic chiasm4 ,note the choroid fissure and the pineal gland1 the latter appearing just beyond the eyes4 ,just forward lies the telencephalon1 or rudiments of the cerebral hemispheres4 ,in a study of the alimentary tract we note that the mouth is bounded by the mandibular arches4 ,note the maxillary processes1 and the ventral surface of the head4 ,a finger-like diverticulum1 extending from the roof of the ruptured double membrane1 formerly separating the pharynx from the arches1 forms the hypophysis4 ,the great development of the visceral pouches makes the pharynx rather complex4 ,in studying sections horizontally through the pharyngeal region note the various visceral arches and pouches4 ,note the arteries of the thyroid diverticulum4 ,in the series note the changed development of the lung rudiments1 the glottis1 the esophagus1 the trachea1 and the bronchi4 ,the bronchi appear in pairs4 ,note that the liver has assumed proportions1 and that it surrounds the common trunk of the vitelline veins1 which it divides into two parts4 ,the sinus venosus lies close to the heart4 ,the ductus venosus is also surrounded by the liver4 ,above the tip of the ventricle we note a dilatation which represents the stomach4 ,the hepatic1 or bile duct is located immediately behind the stomach4 ,this duct is formed by the fusion of the right and the left duct4 ,locate1 draw1 and describe the pancreas2 trace the intestine2 locate the splanchnic umbilicus1 or yolk stalk2 locate the allantois stalk1 and trace its connection with the hind-gut4 ,in the series1 locate and study the ,wolffian ducts1 the beginning of the ,mllerian duct1 the embryonic kidney1 or mesonephros1 the permanent kidney1 or metanephros4 ,the urino-genital ridge is made up of all the above except the last named4 ,the urino-genital ridge forms a rounded projection on each side of the mesentery into the dorsal angles of the body cavity4 ,the ,wolffian ducts empty into the cloaca4 ,there are two ducts which may be traced far forward1 and which are found to extend backward along the lateral margin of the ridge to the cloaca4 ,along the greater part of their length we note tubules emptying into them4 ,beginning near the anterior end of the urino-genital ridge1 we note that the ,mllerian ducts arise from a thickened line of epithelium4 ,the greater part of the ridge is formed by the mesonephros4 ,this is made up of a series of tubules in each of which we may distinguish two parts as follows3 a tuft of capillaries from the aorta forming the glomerules1 surrounded by a thin walled invaginated capsule1 making up the ,malpighian corpuscle2 and the tubules proper4 ,the tubules lead from the corpuscles1 or glomerules1 to the ,wolffian duct4 ,the germinal epithelium constitutes the essential portions of the gonad1 or ovary1 or testis4 ,the germinal epithelium arises from a thickening of the peritoneum of the median wall of the ridge4 ,the gonad is found near the anterior end of the ridge4 ,at about this age of the embryo there should appear the primitive ovary or testis4 ,near the posterior termination of the ,wolffian duct and from the dorsal diverticulum there arises the ureter1 or metanephros duct4 ,in these series there should be studied the heart and circulation1 which will be found similar to the sections from the embryo seventy-two hours old4 ,work out a summary of the relations of the allantois and the yolk stalk to the intestines2 the relations of the ,wolffian ducts to the intestines2 the origin of the ureters from the ,wolffian ducts2 the relations of the lungs1 the liver1 and the thyroid gland2 the relations of the blood-vessels2 a study of the muscle plates2 the relations of epiphysis1 hypophysis1 infundibulum1 mouth1 and pharynx2 the relations of the vagus1 or pneumogastric1 trifacial1 acoustico-facialis1 and glosso-pharyngeal nerves to the visceral arches4 ,in addition to the study of embryos at the end of each of the first four days of incubation1 a study should be made of preserved museum specimens each of which represents the development of a day up to and including the twenty-first day4 ,,the ,,derivatives ,,of ,,the ,,germ-,,layers ,from the three primary germ-layers are developed the various tissues and organs of the body by metamorphoses which may be referred to the two fundamental processes of specialization1 or the adaptation of structure to function1 and of unequal growth1 which latter results in the formation of folds1 ridges1 and constrictions4 ,from the ectoderm are produced3 ,the epidermis and its appendages1 including the nails1 the epithelium in connection to the feathers and the feathers4 ,the infoldings of the epidermis1 including the epithelium of the mouth1 epithelium of the salivary glands and the anterior lobe of the pituitary body1 or hypophysis4 ,the epithelium of the nasal tract with its glands and communicating cavities4 ,the epithelium lining the external auditory canal1 including the outer stratum of the membrana tympani4 ,the lining of the anus4 ,the epithelium of the conjunctiva and of the anterior part of the cornea1 the crystalline lens4 ,the spinal cord1 the brain with its outgrowths1 including the optic nerve1 the retina1 and the posterior lobe of the pituitary body4 ,the epithelium of the inner ear4 ,from the entoderm are produced3 ,the epithelium of the respiratory tract4 ,the epithelium of the digestive tract1 from the back part of the pharynx to the anus1 including its associated glands1 the liver1 and the pancreas4 ,the epithelial parts of the middle ear and of the eustachian tube4 ,the epithelium of the thymus and the thyroid bodies4 ,from the mesoderm are developed3 ,connective tissue in all its modified forms1 such as bone1 cartilage1 lymph1 blood1 fibrous and areolar tissue4 ,muscle tissue4 ,all endothelial cells1 as of joint-cavities1 bursal sacs1 lymph sacs1 blood-vessels1 pericardium1 and endocardium1 pleura1 and peritoneum4 ,the spleen4 ,the kidneys and ureters4 ,the testicles and the system of excretory ducts4 ,the ovary and oviduct4 ,,preparation ,,of ,,structures ,,for ,,study ,it is hoped that the following suggestions will be helpful in the laboratory work4 ,directions for ,dissecting ,muscles4--,the muscles that are brought into great play in movements of the bird's limbs are dark carmine in color1 while those which are not brought greatly into use are pale or white in color4 ,the tendons are made up of white fibrous connective tissue1 are very dense1 and pearly white in color4 ,in securing a bird for dissection of muscles it is best to select one in rather poor flesh1 as the fat is annoying4 ,the bird may be chloroformed or killed in a bell jar by aid of illuminating gas4 ,after the bird is dead pluck all the feathers and immerse it in a #aj per cent4 solution of formaldehyde or of #hj per cent4 alcohol4 ,it is best to puncture the abdominal wall so that the fluid may at once fill the abdominal cavity and more readily gain access to the chest cavity2 and to puncture the skin at various points so that the liquid may more quickly become disseminated among the muscular structures4 ,post-mortem changes quickly take place if these precautions are not taken4 ,the liquid surrounding the carcass should be at least twice the quantity of the bulk of the carcass4 ,the first dissection should be to lay bare the dermal muscles4 ,the dermal muscles are of two kinds1 true dermal and dermo-osseous4 ,the dermal muscles have their origin and insertion in the skin1 and control the movements of the different groups of feathers4 ,the dermo-osseous have their origin on some part of the skeleton1 and insert to the integuments4 ,the dermal muscles vary with the characteristics of the bird1 we do not find all the known dermal muscles in any one specimen4 ,a cock of the ,cornish breed will show these muscles best developed4 ,birds possess an enormous system of minute muscles divided up into an infinite number of fasciculi1 to act harmoniously upon the feather quills and to agitate collectively the plumage4 ,by the aid of a low-power lens the action of the feather muscles in the large quill butts of the wing or the tail may be studied4 ,the muscles may be studied in groups as outlined in the text4 ,make an incision through the skin down to the bone on the superior part of the head1 parallel and close to the base of the upper mandible1 and extending completely across4 ,from the outer end of this make an incision backward and down to the skull and posteriorly4 ,the muscles of the upper part of the neck will then be exposed4 ,the straight incision should extend to about a half inch on the inside of the upper eyelid of the same side4 ,reflect the flap of skin from the top of the skull1 and carefully examine the under side of it in the median line1 where it overlies the frontal region4 ,the dermo-frontalis will be observed if it be present4 ,in many birds1 especially in females1 it may not be discernible1 and may be considered absent4 ,to expose the circumconcha make an incision completely around the ear2 then carefully dissect to the ear base4 ,a dermal circular muscle should be observed4 ,to expose the dermo-temporalis extend the longitudinal incision down the back of the neck to a point between the clavicular heads1 carrying it just through the skin and about one-fourth of an inch to the side of the median line4 ,remove the skin from the throat and the anterior portion of the chest4 ,lay open the alar and parapatagial duplicatures of the skin4 ,this exposes a number of dermal muscles4 ,the dermo-temporalis is now observed to extend from a small depression just above and anterior to the temporal fossa4 ,it makes slight attachments to the temporal muscle1 which it covers1 and extends backward as a thin ribbon-shaped muscle1 the fibers blending with those of the cleido-trachealis1 and becomes lost upon the skin in front and opposite the shoulder-joint4 ,at times its fibers blend with those of the dermo-tensor patagii4 ,as the musculature of the fowl is loosely arranged1 the rest of the dissection is easily done if care be exercised4 ,the ligaments may be dissected after the completion of the study of muscles1 using the same subject or1 a two pound broiler be prepared by killing in the gas chamber1 plucking the feathers and parboiling just till the flesh becomes tender and is easily removed1 it will be observed that all structures can be removed from the points exposing the ligaments distinctly4 ,the ligaments appear swollen and more easily observed for study4 ,directions for the ,study of the ,viscera4--,carefully remove the right and the left abdominal and thoracic walls1 allowing a strip of tissue to remain in the median line to hold the organs in their normal position4 ,to open these cavities it is necessary to use the bone saw and the scalpel4 ,the organs may now be studied from each side4 ,to make a longitudinal section through the median line1 select a small bird1 one weighing not more than #b pounds1 kill1 and preserve in a #aj per cent4 solution of formaldehyde for three days4 ,then with a sharp1 thin1 long-bladed knife make an incision at one sweep through the median line of the body down to the back bone1 and with the bone saw section through the vertebr4 ,if it is difficult to cut through the breast-bone1 saw through before making the incision4 ,in small birds the entire cut may be made without the aid of the saw4 ,directions for the ,study of ,arteries4--,arteries should be injected4 ,veins are usually more or less filled with blood so that the tracing of these is not so difficult as the tracing of uninjected arteries4 ,nerves are white and no difficulty is usually encountered in tracing them4 ,the courses of arteries1 veins1 and nerves are side by side1 and many of them1 as in mammals1 are arranged in the order of veins1 arteries1 nerves1 the veins being in front4 ,the injection apparatus consists of the following parts3 air-compression chamber1 to which is attached a pressure pump4 ,a manometer made of glass tubing #f millimeters in diameter1 inside measurement4 ,this tube is partly filled with mercury1 and a scale in centimeters is made from the top of the right-hand tube 7,fig4 #hd1 ,no4 #h74 ,this ruling1 or gauge1 should be about #ae centimeters long4 ,extending from the right extremity of the ,u-tube is a small rubber tubing which is attached to the chamber containing the injection fluid2 and extending from the inferior part of this chamber is another tubing which has the injection needle attached to the free end4 ,the injection should be done under #abj millimeters pressure4 ,the stop cock of the pressure chamber is released sufficiently to raise the mercury in the ,u-tube six centimeters1 which multiplied by #b1 the amount of work required to raise two columns1 makes #abj millimeters pressure4 ,if this pressure be maintained1 all vessels should be injected without rupture4 ,the same process may be used in injecting the air cells through the trachea4 ,the injecting material may consist of one part finely sifted plaster of ,paris1 four parts water1 and sufficient gentian violet to make a violet color4 ,for the coloring1 red aniline may be used in preparing this material4 ,the dye should be dissolved in the water to be used in making the injection liquid4 ,caution must be used and the work rapidly done1 as the plaster soon sets1 or becomes solid1 in the needle or in the tubing4 ,a small cannula should be used1 since the endothelial lining of the arteries are easily injured and difficulty may thus be created4 ,select for arterial dissection an old cock1 as in a bird of this kind the arteries are larger and the difficulties are reduced4 ,select for bleeding and injection the ischiadic artery in the thigh region4 ,with the sharp point of the thin blade of a knife make an incision lengthwise of the artery being careful not to strip back the endothelial lining of the artery4 ,allow as much of the blood as will escape before injecting2 in fact1 the arteries should be thoroughly emptied1 so that there is no longer danger of a clot's plugging some vessel and thus preventing its filling4 ,since the blood of most birds coagulates in about thirty seconds1 this work must be done rapidly1 care being exercised to keep the flow running as long as possible4 ,after bleeding is completed1 insert the cannula and tie the vessel tightly around the cannula to prevent the escape of the injecting fluid4 ,see that all connections are sufficiently tight to prevent the escape of liquid under pressure4 ,after the injection is completed1 remove the cannula and tie the artery with a small twine1 preferably cotton4 ,quickly remove all injecting fluid from the needle1 the tubing1 and the injecting chamber4 ,during the operation of bleeding the cock may be chloroformed1 care being taken not to administer chloroform to kill him2 for it is necessary to maintain life as long as possible so that the heart may be kept beating and all blood possible drained from the arteries4 ,after the injection is completed the bird may be plucked and immersed in the preservative fluid in the same manner as in the preparation for dissection for muscles4 ,the arteries1 the veins1 and the nerves may now be dissected and studied in relation to one another and in relation to the muscles1 the bones1 and other structures4 ,the skin should not be removed from the shanks till it is desired to dissect these parts1 as the tissues quickly dry out4 ,in fact1 the tendons of the shanks and toes can best be dissected while the specimen is fresh4 ,a ,study of the ,structure of ,bones4--,longitudinal and transverse sections of old bone may be made by making thin longitudinal and transverse sections with the bone saw1 and then by making them very thin with a fine three-cornered file4 ,examining under the low power microscope1 we note the lacun1 the canaliculi1 and the ,haversian system4 ,similar sections in green bone may be studied if prepared as follows4 ,secure specimen of bone just removed from a fowl and place it for three days in a #aj per cent4 aqueous solution of hydrochloric acid4 ,test by puncturing with a needle1 and1 if all the mineral salts are removed1 place in a water bath and wash for four hours4 ,pass it through the fluids usually employed in preparing specimens for sectioning with the microtome4 ,stain as sections of other tissue for microscopic study4 ,see the description below4 ,if the ends of the bone be included1 it will enable the student to study not only compact bone but also cancellated bone and articular1 or hyaline cartilage1 and in some of the bones1 as the femur1 the red marrow4 ,special ,technic for the ,dissection of ,cranial and ,spinal ,nerves4--,it is rather difficult to dissect the cranial and spinal nerves of the fowl1 owing to the fact that the structures are very small4 ,the bone is rather hard and the nerve tissue so delicate that great skill must be attained to achieve any degree of success4 ,a simple technic has been developed as follows3 ,place the head and neck1 or other structures of the spinal column in a #aj per cent4 aqueous solution of hydrochloric acid for three or more days1 the time depending on the size of the specimen and the amount of soft structures surrounding it4 ,this solution removes all the calcium salts from the bone and makes the removal of the bony structures a less difficult task4 ,directions for the ,study of ,soft ,structures4--,secure a specimen of the tissue to be studied--lung1 muscle1 intestine1 liver1 pancreas--from a normal fowl just killed4 ,the specimen should be not more than inch square4 ,after first hardening three days in #aj per cent4 formaldehyde4 ,pass through the following fluids3 #a4 ,alcohol1 #ie per cent4 #bd hours #b4 ,alcohol1 absolute #bd hours #c4 ,alcohol and ether1 equal parts #bd hours #d4 #a per cent4 celloidin #bd hours #e4 #b per cent4 celloidin #bd hours #f4 #d per cent4 celloidin #bd hours #g4 #f per cent4 celloidin #bd hours #h4 #aj per cent4 celloidin #bd hours #i4 ,place on block1 and as soon as solid1 place in #hj per cent4 alcohol until ready to section4 ,histoloid or parlodion will take the place of celloidin4 ,in placing specimen on the block be careful that the specimen lies conveniently for cutting the sections in the right direction4 ,as soon as the surface has hardened a little1 add a few drops of thick celloidin1 and repeat until there is a good body of celloidin4 ,allow to stand until the tissues are quite firmly fastened to the block1 but not long enough to permit shrinking4 ,then place in #hj per cent4 alcohol until the specimen is perfectly firm1 #ab or more hours1 before cutting4 ,all tissues1 cut sections1 and mounted blocks are to be placed in #hj per cent4 alcohol4 ,as containers for this purpose shell vials will be most handy4 ,cut the sections with the microtome as thin as possible1 the thinner the better4 ,the following process of staining will make the nucleus blue and the cytoplasm reddish4 #a4 ,float section in a tumbler of tap water4 #b4 ,place section on slide1 and immerse in hematoxylon for five to ten minutes4 #c4 ,immerse in acid alcohol from two to five seconds4 #e4 ,place on slide1 and immerse in eosin from one-half to three minutes4 #f4 ,wash thoroughly in alcohol4 #g4 ,clarify in oil of cloves1 oil of cedar1 or beechwood creosote1 ten minutes4 #h4 ,mount in balsam4 #i4 ,label and study4 ,delafield's hematoxylon is prepared as follows3 ,hematoxylon crystals #d grams ,alcohol1 #ie per cent #be c4c4 ,saturated aqueous solution of ammonia alum #djj c4c4 ,add the hematoxylon dissolved in the alcohol to the alum solution1 and expose in an unstoppered bottle to the light and air for three or four days4 ,filter and add3 ,glycerin #ajj c4c4 ,alcohol1 #ie per cent4 #ajj c4c4 ,allow the solution to stand in the light until the color is sufficiently dark2 then filter1 and keep in a tightly stoppered bottle4 ,the solution keeps well and is extremely powerful4 ,so long as it is good the solution has a purplish tinge4 ,if time permits1 it would be wise to combine the alum1 the hematoxylin1 and the water1 and to ripen the solution for two or three weeks before adding the other ingredients1 which have a tendency to prevent oxidation4 ,the acid alcohol is made as follows3 ,absolute alcohol #gj c4c4 ,distilled water #cj c4c4 ,mix4 ,above solution #ii c4c4 ,hydrochloric acid #a c4c4 ,eosin is sold in two forms1 that soluble in water and that soluble in alcohol4 ,the eosin soluble in water is preferred1 because with it a greater degree of diffusion in stain can be obtained4 ,keep on hand a saturated aqueous solution and dilute with water as needed4 ,the strength of the solution to be used varies somewhat with the tissue and the reagent in which it is to be fixed2 but usually the strength should be between and per cent4 when eosin is used after hematoxylin4 ,the diluted solutions should contain #be per cent4 of alcohol1 otherwise they will not keep well4 ,when eosin is used before an aniline dye1 such as methylene blue1 a #e per cent4 or even a saturated solution should be used4 ,to ,stain ,sections of ,liver for the ,study of ,kupffer ,cells4--,to bring out this reaction ,keys suggests the following technic3 ,fix small blocks of the fresh tissue of spleen or liver for eighteen to twenty-four hours in ,mller's fluid plus #e per cent4 mercuric sublimate4 ,imbed in paraffin and section to #d microns4 ,fix sections to slide1 and stain twenty to forty minutes with acid carmine4 ,wash1 and transfer to equal parts of a #b per cent4 aqueous solution of potassium ferrocyanid and of a #b per cent4 aqueous solution of hydrochloric acid4 ,remove after three to ten minutes1 wash in distilled water1 and pass quickly through a #j4e per cent4 aqueous erythrosin solution4 ,dehydrate in alcohol1 clarify in xylol1 and mount in ,canada balsam4 ,to ,prepare ,anatomical ,specimens for a ,museum4--,the ,keiserling method gives the best results1 since by this method the tissues retain their normal color4 ,the three steps are as follows3 #a4 ,place the specimen in the following solution and leave from one to seven days1 the length of time depending upon the size of the specimen4 ,formalin #bjj c4c4 ,potassium acetate #cj grams ,potassium nitrate #ae grams ,water #ajjj c4c4 #b4 ,pass the specimen through each of the following solutions1 leaving it in each twenty-four hours or until the normal color is obtained4 ,the specimen should be removed from alcohol as soon as color is attained4 ,if it is left in the alcohol too long it will again lose some of its color4 ,alcohol #dj per cent4 ,alcohol #fj per cent4 ,alcohol #hj per cent4 ,alcohol full strength #c4 ,place the specimen in the following permanent solution1 label1 and place in museum4 ,glycerin #dj c4c4 ,potassium acetate #dj grams ,distilled water #djj c4c4 ,a small piece of thymol must be placed on the top of the liquid in each jar1 or mold will develop and spoil the specimen4 ,to ,make ,specimens ,transparent4--,specimens may be rendered transparent by the method of ,spalteholz4 ,the steps are essentially as follows3 ,i4 ,preparation of the fresh tissue4 ,if any parts are to be made conspicuous1 as blood-vessels1 or the lymphatic system1 they must be injected with an insoluble1 unbleachable substance4 ,spalteholz recommended carmine or methylene blue1 and carbon4 ,i have found ,higgin's ordinary black carbon ink excellent for this purpose4 ,the system or systems are injected with this substance while the tissue is perfectly fresh4 ,,ii4 ,fixation4 ,the tissues are fixed preferably in #aj per cent4 formalin4 ,the length of time for fixation depends on the size of the tissue4 ,in formalin it requires from eight hours upward to fix completely4 ,,iii4 ,rinsing4 ,running tap water for five or ten minutes accomplishes the rinsing4 ,if it is impracticable to pass directly into the bleaching fluid1 the tissues may be kept temporarily in #fj per cent4 or #gj per cent4 alcohol4 ,they should then be rinsed again thoroughly in water when ready to bleach4 ,,iv4 ,bleaching4 ,the bleaching fluid used is hydrogen peroxid to which ammonia is added until a white precipitate forms4 ,the proportion is approximately two parts of peroxid and one of ammonia4 ,the material is bleached until all the color is removed and the tissue looks perfectly clear or slightly opaque4 ,it may be quite transparent as the protein coagulate is somewhat white1 but all yellow or reddish color should be bleached away4 ,v4 ,washing4 ,rinse thoroughly in running tap water or through several changes of water until the odor of ammonia is quite gone4 ,,vi4 ,dehydration4 ,pass gradually through alcohol solutions1 #cj per cent41 #ej per cent41 #fj per cent41 #gj per cent41 #hj per cent41 #ie per cent41 and last through absolute alcohol4 ,the time required for dehydration will vary with the size of the material1 but in either #ie per cent4 solution or in absolute alcohol the tissue should remain until well hardened1 twenty-four hours or more4 ,dehydration is completed by passing from absolute alcohol1 to a fluid one-half absolute alcohol and one-half benzol2 thence for a few days to pure benzol4 ,,vii4 ,clarifying4 ,from benzol the material is finally clarified in winter-green oil or any other standard clearer1 and put up in its final position in the museum jar4 ,in commenting on this method ,dr4 ,a4 ,f4 ,contant says3 8,i have found this to work very successfully in the injection of the lymphatics of the human skin1 which1 as you know1 is a rather delicate injection and has been difficult of demonstration by other methods4 ,with this method1 however1 ,i have prepared whole portions1 as the side of the face1 the leg1 etc41 of small animals and embryos which show clearly the whole course of the lymphatic vessels and nodes1 in situ1 and their relations to surrounding parts40 ,,equipment ,,for ,,the ,,dissection ,,laboratory ,figure #hd illustrates some essential equipment for the dissection laboratory4 ,the equipment should consist of a pump1 ,no4 #a1 which forces air through the rubber tube1 ,no4 #b1 into the pressure tank1 ,no4 #d1 which is guarded by the valve at ,no4 #c4 ,a dial1 ,no4 #e1 indicates the pressure of the air within the tank4 ,the air as needed is released through an outlet valve4 ,the air now passes through the rubber tube1 ,no4 #f1 into the left arm of the manometer at ,no4 #g4 ,the manometer is simply a glass tubing filled with mercury to the point indicated at ,no4 #g4 ,by the side of the opposite arm there is made a scale graduated in centimeters4 ,the tube at ,no4 #i being attached to the ,y-tube1 conveys air under the same pressure into the injection chamber as that supporting the column of mercury of the manometer4 ,it is necessary to have a pinch cock1 as indicated at ,no4 #aa1 to control the liquid within the tube4 ,no4 #ab illustrates the tube in the end of which1 ,no4 #ac1 there is inserted a trocar which is introduced into the artery and tightly tied with a cord4 ,illustration3 ,,fig4 #hd4--,photograph showing injection apparatus1 dissection instruments1 dissection pan and death chamber4 #a1 ,pump4 #b1 ,rubber tube leading from pump to compression chamber4 #c1 ,stop cock4 #d1 ,compression air tank4 #e1 ,pressure indicator4 #f1 ,rubber tube leading from pressure tank to manometer4 #g1 ,top of mercury in manometer tube4 #h1 ,open end of glass tube showing scale in centimeters4 #i1 ,tube leading from #d to injection chamber4 #aj1 ,injection chamber containing injection fluid4 #aa1 ,pinch cock on rubber tube connecting injection chamber with injection canula4 #ab1 ,the tube4 #ac1 ,injection canula4 #ad1 ,a metal dissection tray4 #ae1 ,death chamber4 #af1 ,base of same4 #ag1 ,rubber tube connecting gas cock with death chamber4 #ah1 ,bone saw4 #ai1 ,bone cutter4 #bj1 ,scapula4 #ba1 ,tenaculum4 #bb1 ,forceps4 #bc1 ,straight scissors4 #bd1 ,small pair of curved scissors4 ,a convenient dissection tray may be made from galvanized iron4 ,it should be #af inches square and about #a inch deep 7,fig4 #hd1 ,no4 #ad74 ,a death chamber is made by using a bell jar #ab inches in diameter at the bottom4 ,this is used on a perfectly smooth board #af inches square4 ,through the center of this board is inserted a glass tube inch in diameter4 ,to this glass tube is attached a rubber tube the other end of which is attached to a gas jet4 ,the instruments needed in dissecting are illustrated in ,fig4 #hd4 ,no4 #ah is a bone saw2 ,no4 #bj is a scalpel2 ,no4 #ba is a tenaculum2 ,no4 #bb is a pair of forceps2 ,no4 #bc is a pair of straight scissors2 and ,no4 #bd is a small pair of curved scissors4 ,,bibliography ,,baum ,,and ,,ellenberger1 ,handbuch der ,vergleichenden ,anatomie1 ,berlin1 #aiab4 ,,barrows1 ,h4 ,r41 ,me4 ,e4 ,s4 ,bull4 #bcb1 pp4 #af1 plates #f1 #aiad4 ,,bradley1 ,o4 ,,charnock1 ,the ,structure of the ,fowl1 pp4 #adf1 illustrations #gc4 ,,chaveau1 ,a41 ,comparative ,anatomy of ,domestic ,animals1 ,new ,york1 #ahic4 ,,curtis1 ,m4 ,r41 ,ligaments of the ,oviduct of the ,fowl1 ,me4 ,e4 ,s4 ,bull4 #bjf1 #aiaj4 ,,duval1 ----1 ,atlas of ,embryology4 ,,foster ,,and ,,balfour1 ,elements of ,embryology4 ,,gadow1 ,h41 ,,and ,,selenka1 ,e41 ,vgel4 ,i4 ,anatomischer ,theil 7,dr4 ,h4 ,g4 ,bronn's ,klassen und ,ordnungen des ,thier-,reichs4 ,sechester ,band1 ,vierte ,ahtheiburg71 ,leipsig1 #ahia4 ,,gray1 ,,henry1 ,anatomy ,descriptive and ,surgical1 ,new ,york1 #aijh4 ,,heisler1 ,j4 ,c41 ,embryology1 ,philadelphia1 #aija4 ,,kaupp1 ,b4 ,f41 ,male ,reproductive ,organs of the ,fowl1 ,am4 ,jr4 ,vet4 ,med41 vol4 x1 #aa1 #b4 ,,kaupp1 ,b4 ,f41 ,female ,reproductive ,organs of the ,fowl1 ,am4 ,vet4 ,rev41 vol4 #di1 #aa1 #d4 ,leisering ,atlas of ,anatomy1 edited by ,w4 ,,ellenberger1 translated by ,a4 ,t4 ,,peters1 ,chicago1 #aije4 ,,lillie1 ,f4 ,r41 ,embryology of the ,chick1 ,chicago1 #aijf4 ,,owen1 ,r41 ,comparative ,anatomy and ,physiology of ,vertebrates1 ,london1 #ahff4 ,,schmeisser1 ,h4 ,c41 ,a ,study of the ,blood of ,fowls1 ,johns ,hopkins ,hospital1 #aiae4 ,,shufeldt1 ,r4 ,w41 ,myology of the ,raven1 pp4 #cah1 illustrations #gf1 ,london1 #ahij4 ,strangeways' ,veterinary ,anatomy1 edited by ,i4 ,,vaughan1 ,edinburgh1 #ahib4 ,,surface1 ,f4 ,m41 ,histology of the ,oviduct of the ,fowl1 ,me4 ,e4 ,s4 ,bull41 #bjf1 #aiab4 ,,index ,abdominal air-sac1 #bjb cavity1 #aef ,abducens nerve1 #bgj ,abductor minimi digiti muscle1 #aaj ,accessorius spinalis nerve1 #bgd ,accessory organs of digestion1 #aeb ,acetabulum1 #dh ,achillis tendon1 #fi ,acoustic lamina1 #cbc nerve1 #cjf vesicle1 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