Part 102

Vertebræ, false, 24 fixed, 24 foramen, 25 hæmal spine, 25 ligaments of, of dog, 204 of horse, 172 of ox, 203 of pig, 204 lumbar, 24 of dog, 151 of horse, 38 of ox, 112 of pig, 138 mammillary processes, 25 movable, 24 notches, 25 of horse, intercentral articulations of, 173 interneural articulations of, 173 ossification of, 25 primary centers of ossification, 25 sacral, 24 of dog, 151 of horse, 39 articulations of, 175 development, 41 of ox, 114 of pig, 138 secondary centers of ossification, 25 spinous process, 25 thoracic, 24 of dog, 150 of horse, 35, 36, 37 of ox, 112 of pig, 137 transverse processes, 25 true, 24 ventral spine, 25

Vertebral artery, 540 of dog, 633 of ox, 609 of pig, 627 canal, 25 of horse, 42 column, 24 of dog, 150 of horse, 31 of ox, 112 of pig, 136 foramen, 25 formula, 24 groove of horse, 42 ligaments of dog, 204 of horse, 172 of ox, 203 of pig, 204 notches, 25 vein, 586

Vertex corneæ, 741

Vertical septum of metacarpus of ox, 130

Vesical artery, 574

Vesicles, seminal, of dog, 506 of horse, 491 of ox, 502 of pig, 505

Vesico-genital pouch, 356

Vesico-prostatic artery, 574

Vestibular ganglion, 686 nerve, 686, 761

Vestibule of ear, 758

Vestibule of larynx of horse, 447 of omental cavity, 380

Veterinary anatomy, 17

Vibrissæ, 763

Vidian canal of horse, 51, 61 nerve, 681

Villi of articulations, 170

Visceral layer of pericardium, 525 pleura of horse, 452

Vitreous body, 746 of ox, 774

Vocal cords, false, of dog, 467 of horse, 447 of ox, 459 of pig, 465 true, of dog, 468 of horse, 448 ligament of horse, 444 process of horse, 443

Vocalis muscle of horse, 446

Volar arch, 562 artery, deep, 562 of second phalanx, 564 common digital artery of ox, 614 digital nerves of dog, 731 flexion of joints, 171 foramen of third phalanx, 91 ligament of carpal joints, 183 of pastern joint, 188 muscle of pig, 315 nerve of horse, 701 of ox, 718, 719 plexus, 595 sesamoids of dog, 165

Vomer of dog, 158 of horse, 63, 431 of ox, 122 of pig, 143

Vomero-nasal organ, 772 of horse, 440

Vortex cordis of horse, 534

V-shaped ligament, 188

Vulva of bitch, 523 of cow, 519 of mare, 514 of sow, 522

Vulvar cleft of mare, 514

Wall of horse’s hoof, 764

White commissure of cord, 650 line of hoof, 765 matter of nervous system, 644

Wilson’s muscle of dog, 507 of ox, 504

Winslow’s foramen, 379 of ox, 396

Wirsung’s duct of horse, 372

Wolf tooth, 339 of horse, 58, 64

Wool, 777

Xiphoid cartilage, 26 of horse, 46

Y-shaped ligament, 188

Zone, epigastric, of horse, 353 hypogastric, of horse, 353 intermediate, of kidney, 473 mesogastric, of horse, 353

Zonula ciliaris, 743, 747 of Zinn, 747

Zygomatic arch of horse, 56, 67 bones of horse, 62 crest of horse, 58, 62 gland of dog, 427 nerve of dog, 728 of horse, 679 process of frontal bone, 55 of maxillary bone, 58

Zygomatic process of temporal bone, 56

Zygomatico-auricularis, 749 of ox, 747

Zygomaticus muscle of dog, 318 of horse, 215 of ox, 295 of pig, 311

Footnote 1:

Only the gross structure is discussed here. For the microscopic structure reference is to be made to histological works.

Footnote 2:

Only a brief general statement of osteogenesis can be made here; details must be sought in embryological literature.

Footnote 3:

As might be expected from the history of anatomy, a good many of these terms are more or less interchangeable; furthermore, a given skeletal feature may differ greatly in various species.

Footnote 4:

The term is employed here, as is usual in descriptive anatomy, to designate only the bony part of the rib (Os costale); morphologically it includes the cartilaginous part also.

Footnote 5:

The manubrium sterni of man is equivalent, strictly speaking, to the cariniform cartilage + the first osseous segment of the horse.

Footnote 6:

The long axis of the skull is considered to be horizontal in these descriptions.

Footnote 7:

The occipital crest of this description is equivalent to the external occipital protuberance and superior nuchal line of man. A curved line a little lower down, which is continued on the paramastoid process, represents the inferior nuchal line of man.

Footnote 8:

Other terms for these parts are basioccipital (basilar part), exoccipitals (lateral parts), and supraoccipital (squamous part). It should be noted, however, that the lines between the basioccipital and exoccipitals pass through the lower part of the condyles.

Footnote 9:

This foramen might well be called a canal, since it is an inch or more in length.

Footnote 10:

The cavity so formed may be termed the sphenopalatine sinus. The sphenoidal sinus may be a separate cavity which communicates only with the ventral ethmoidal meatuses; this arrangement exists in about a third of the cases, according to Paulli.

Footnote 11:

This is also called the subsphenoidal canal or pterygoid foramen.

Footnote 12:

On account of its deep situation, and the fact that it cannot be separated from its surroundings, the ethmoid must be studied by means of appropriate sagittal and transverse sections of the skull.

Footnote 13:

According to Martin, there are originally four centers, two anterior and two posterior (smaller) ones, which fuse in a variable manner.

Footnote 14:

This is commonly termed the styloid process. It is not the homologue of the styloid process of man.

Footnote 15:

This foramen is somewhat variable in position, but is commonly opposite the corner incisor. Smaller inconstant foramina are often present.

Footnote 16:

The alveolus for the temporary canine is commonly formed in the maxilla alone.

Footnote 17:

This bone is really a greatly developed first ethmoturbinal.

Footnote 18:

In the Stuttgart Nomenclator Anatomicus (S. N. A.) the body (Corpus) is the part which bears the teeth, and is divided into a pars incisiva and a pars molaris. The ramus is the rest of the bone.

Footnote 19:

These correspond to the great cornua of man.

Footnote 20:

This relation varies with age; in the young horse the third tooth, in the old subject the fourth, lies below the end of the crest.

Footnote 21:

This bone is probably equivalent to the fourth and fifth carpals of forms in which five carpal elements are present in the lower row.

Footnote 22:

It is also called the large pastern bone or os suffraginis.

Footnote 23:

This bone is also called the small pastern bone or os coronæ.

Footnote 24:

This bone is also called the os pedis or coffin bone.

Footnote 25:

The upper and lower divisions of the wing are sometimes termed the basilar and retrossal processes respectively.

Footnote 26:

This is termed the lacrimal sinus by some authors. It is similar in location and in the position of its orifice to the turbinal part of the frontal sinus of the horse, with the important difference that it does not communicate with the frontal sinuses in the ox.

Footnote 27:

This third bone was termed the phacoid in the cat by Strauss-Durckeim, and is regarded by some authors as the vestige of an additional digit, the prepollex.

Footnote 28:

It is doubtful whether the synovia is a true secretion or a transudate containing products of friction. The view given above is that which is more commonly accepted.

Footnote 29:

This classification makes no claims to scientific accuracy, but is simply a statement of the terms in general use. A grouping based on mechanical principles seems desirable, but appears to be almost impossible on account of the great variety and irregularity of form of the articular surfaces.

Footnote 30:

The movements in some of these joints are more extensive and varied than in some diarthroses. To illustrate this we may compare the movements of the cervical or coccygeal vertebræ with those possible in the carpo-metacarpal or the sacro-iliac joints.

Footnote 31:

In dissecting-room subjects these bursæ and the adjacent structures are commonly the seat of pathological changes. They appear to be the starting-point of “poll evil” and “fistulous withers.”

Footnote 32:

No natural line of demarcation exists between the ligamentum nuchæ and the lumbo-dorsal continuation of the supraspinous ligament, since the change from the purely elastic to the white fibrous structure is gradual.

Footnote 33:

The term is a very unfortunate one, since it is a distinct misapplication of the name as it is used in regard to man. It is, however, very firmly established, and appears likely to persist indefinitely in the absence of a convenient popular equivalent.

Footnote 34:

This is often called the Y-shaped ligament—a rather undesirable name, since it is not bifurcate.

Footnote 35:

It is also called the V-shaped ligament.

Footnote 36:

This should be noted in regard to resection of the lateral cartilage or other operations in this vicinity.

Footnote 37:

These are termed the postero-lateral ligaments by M’Fadyean. They may well be called, as by German authors, the suspensory ligaments of the navicular bone.

Footnote 38:

In this figure the patella is pushed up above the trochlea—a position which it does not occupy normally.

Footnote 39:

This section consists necessarily only of a brief statement of the most important differences in the joints of the other animals.

Footnote 40:

These movements are best seen in man, in whom the back of the hand may be turned forward (pronation) or backward (supination).

Footnote 41:

The student will note in dissection that transition forms occur; also that the same sheath may belong to two or more tendons in common, _e. g._, the sheath of the two flexors on the back of the carpus. In such cases the synovial membrane is reflected from one tendon to the other, and may form a secondary mesotendon.

Footnote 42:

This muscle is probably the homologue of the sternal portion of the sterno-cleido-mastoid of man. On account of the differences in its insertion in the various animals, it seems desirable to adopt the name sterno-cephalicus.

Footnote 43:

The upper part of this maybe separated from the scalenus proper, and is then termed the cervicalis ascendens or ilio-costalis cervicis—a continuation in the neck of the transversalis costarum.

Footnote 44:

This seems due to pressure produced by pathological changes in the supra-atloid bursa, which are frequently extensive in dissecting-room subjects.

Footnote 45:

The lumbar part of this muscle is subject to variation. It may, in quite exceptional cases, extend as far as the ilium.

Footnote 46:

The muscle as here described includes the spinalis and semispinalis components, as the separation of these is largely artificial in the horse.

Footnote 47:

The function of the intercostal muscles is still a subject of much discussion. The statements made above seem to represent the view most commonly held in regard to their action.

Footnote 48:

It should be noted, however, that in the embryo the diaphragm appears as a paired structure, extending from the lateral walls of the cœlom to fuse with the septum transversum.

Footnote 49:

In order to get a clear idea of the relative positions of these foramina and of the form of the diaphragm, the thoracic surface of the latter should be examined while the abdominal viscera remain _in situ_.

Footnote 50:

It is narrow and slit-like in the natural condition, but may appear oval in the dissecting-room, especially if the hind limb is drawn back and abducted.

Footnote 51:

It must be admitted that the term “ring” is rather misleading as applied to the abdominal opening of the canal, since normally it is a mere dilatable slit. The ring-like constriction which exists here in the male is constituted by the peritoneum, which descends into the canal to form the tunica vaginalis. This peritoneal ring is termed the =vaginal ring= (Annulus vaginalis), and must not be confused with the subperitoneal ring, _i. e._, the internal inguinal ring.

Footnote 52:

As might be expected, the cremaster usually undergoes more or less atrophy, and is paler in the castrated subject. In the mare the muscle is small, and ends in the connective tissue in the lower part of the inguinal canal.

Footnote 53:

The term canal is somewhat misleading; it is rather a slit-like passage or space between the two oblique muscles, since the inguinal ligament is that part of the aponeurosis of the external oblique muscle which stretches between the external angle of the ilium and the prepubic tendon.

Footnote 54:

The obliquity of the tendon and the angle which it forms with the pelvic floor are of clinical importance in regard to manipulation of the fœtus in obstetrical cases. The slope varies in different subjects. In some cases the tendon forms about a right angle with the pubic bones.

Footnote 55:

The terms dorsal and ventral are here used in the topographic and not in the morphological sense. All the muscles of the group are ventral in the latter sense.

Footnote 56:

This is regarded as a vestige of the clavicle. On this basis the portion of the muscle from the vestige to the arm represents the clavicular part of the deltoid of man.

Footnote 57:

Günther states that this muscle assists in extension or flexion according to the position of the head of the humerus relative to the glenoid cavity.

Footnote 58:

M’Fadyean and Vaughan term this muscle the scapulo-ulnaris, while Arloing and Lesbre term it “Ancone accessoire du grand dorsal.” The above name seems to agree best with the chief insertion and action, although it certainly arises largely from the tendon of insertion of the latissimus dorsi.

Footnote 59:

This is considered to represent the part of the common extensor for the fourth and fifth digits.

Footnote 60:

Martin considers that this muscle represents the extensor indicis proprius and the part of the common extensor for the second digit.

Footnote 61:

In man the muscle is an extensor of the hand.

Footnote 62:

On account of the intimate union between the psoas major and iliacus they are frequently considered a single muscle, to which the name ilio-psoas is applied; some anatomists include the psoas minor also under this term.

Footnote 63:

By some anatomists the portion inserted into the crest is termed the gluteus accessorius, but Lesbre considers this the deep gluteus, homologous with the gluteus minimus of man. The portion inserted into the trochanteric ridge apparently represents the piriformis of man.

Footnote 64:

Apparently the muscle represents the biceps, together with part of the gluteus superficialis of man. Hence the names gluteo-biceps and paramero-biceps have been suggested.

Footnote 65:

This muscle was incorrectly designated the adductor magnus by Percivall and Strangeways. Its name, however, is not at all descriptive of its structure in the domesticated animals.

Footnote 66:

It has been customary to describe two adductors—a parvus or brevis, and a longus or magnus. This division is largely artificial, and has been abandoned in the new nomenclature—a return to the views of Bourgelat and Girard.

Footnote 67:

This has been termed by various authors the adductor parvus or brevis.

Footnote 68:

Termed by various authors the adductor magnus or longus.

Footnote 69:

The iliac head is described by some authors as a separate muscle, and termed the pyriformis. This does not seem desirable, especially since it is at least probable that the homologue of the pyriformis of man is that portion of the middle gluteus which is inserted into the back of the trochanteric ridge.

Footnote 70:

The name is based on the arrangement in man, in whom the muscle consists of two fasciculi forming a groove between them for the tendon of the obturator internus. In the horse it is undivided, and is grooved for the obturator tendon, so that at first sight it appears to be double. The gemellus may be regarded as the extrapelvic head of the obturator internus (Gegenbaur).

Footnote 71:

While it is true that the separation of the intermedius is probably never entirely a natural one in the horse, it varies in individual cases, and is usually clear on cross-sections. In some subjects it is possible to separate another slip which may represent the articularis genu of man.

Footnote 72:

It seems inadvisable to retain the old nomenclature, since it is inapplicable to other domesticated animals in which the muscle is well developed (_e. g._, ox, pig).

Footnote 73:

The soleus may, therefore, be included with the two heads of the gastrocnemius under the name triceps suræ.

Footnote 74:

The origins of these heads are given in the order in which they may be most conveniently dissected, not in order of size and importance.

Footnote 75:

This is probably the homologue of the subclavius of man.

Footnote 76:

Movements of individual digits are specified with regard to the axis of the manus (hand, paw), and not to the median plane of the body.

Footnote 77:

The term “mouth” is commonly used to signify either the oral cavity (Cavum oris) or the entrance to it (Rima oris).

Footnote 78:

The epiglottis may be either in front of or behind the soft palate; most often it is prevelar.

Footnote 79:

In the undisturbed state of the parts there is no space between the tongue and the rami of the lower jaw; consequently the tongue must be drawn aside to see the sublingual crest.

Footnote 80:

It will be noted that this definition of crown and root does not agree exactly with the popular view that the crown is the free portion and the root the embedded portion. The objection to the latter statement lies in the fact that it is not capable of general application. Thus the morphological crown of the permanent molars in the horse is extremely long, and is, for the most part, embedded in the bone in the young animal. The root proper begins to form at four or five years of age, and continues its growth for about eight years. As the exposed part of the crown wears down, the embedded part pushes out of the alveolus, thus preventing deficiency of length. On the old basis we should have to say that successive portions of the root become crown, while in point of fact it is only in very extreme age that the true root comes into wear.

Footnote 81:

Ellenberger found, as the result of extensive observations (8000 subjects), that about 2 to 3 per cent. of mares have erupted canines in both jaws; that 6 to 7 per cent. have them in the upper jaw; while 20 to 30 per cent. have them in the lower jaw.

Footnote 82:

It is interesting to notice that vestigial canines are not at all uncommon in mares, especially in the lower jaw. They are very small, and do not usually erupt; their presence is indicated in the latter case by a prominence of the gum. This is in conformity with the fact that they were present in both sexes in Eocene and Miocene ancestors of existing equidæ.

Footnote 83:

It is common in veterinary works to call all the cheek teeth molars, since, in the horse particularly, the premolars are molariform, _i. e._, do not differ materially from the true molars in size or form. The term cheek teeth conveniently includes the premolars and molars.

Footnote 84:

The student is advised to amplify these very general statements by the examination of heads of subjects of varying ages. It may also be noted that the position of the septum between the two divisions of the sinus varies much.

Footnote 85:

Careful observations (especially on frozen subjects and those in which the organs have been hardened _in situ_) show that there is no abdominal part of the œsophagus in the strict sense of the term. The stomach here lies directly on the diaphragm, so that the last inch or so of the œsophagus is placed obliquely in the hiatus œsophageus, and is partly covered by the pleura, but not by peritoneum. In soft subjects the weight of the stomach, or traction on it, draws part of the œsophagus into the abdomen, inclosed in a collar of peritoneum.

Footnote 86:

The potential lumen is difficult to determine at all accurately. When distended, its diameter (according to Rubeli) varies from 5.7 cm. at its origin to 4 cm. at its cardiac end. The thickness of the wall varies (inversely as the lumen) from 4 mm. to 1.2 cm. or more.

Footnote 87:

At the origin of the tube muscular bundles arise on the raphé pharyngis and blend with the crico-pharyngeus. Ventrally fibers come from the depression between the cricoid and arytenoid cartilages. Bundles of striped fibers may be continued in the superficial part of the muscular coat as far as the cardia.

Footnote 88:

This method of division, although long in use, is of very little value for accurate description. It is mentioned here chiefly because agreement on a more useful topographic method has not been arrived at.

Footnote 89:

Only a general account of the arrangement of the peritoneum is given in this section, since a detailed description cannot be understood without a knowledge of the viscera concerned.

Footnote 90:

This is the position in the expiratory phase as usually seen in the dead subject. In inspiration the saccus cæcus lies under the upper parts of the sixteenth and seventeenth ribs.

Footnote 91:

This occlusion is usually so complete that distention of the stomach by air or fluid forced in through the pylorus may be carried far enough to rupture the stomach without ligating the œsophagus.

Footnote 92:

No natural line of demarcation exists, but there is a marked increase of the thickness of the wall toward the terminal part. Other differences will be noted in the further description.

Footnote 93:

It will be noticed that the mesoduodenum is not continuous with the great mesentery, but ends by a free edge. The mesentery begins on the opposite surface of the end of the duodenum, so that the bowel is attached by two peritoneal folds at this point.

Footnote 94:

Abnormal displacement, _e. g._, torsion of the left parts, is not rare, and is liable to produce death if not promptly reduced.

Footnote 95:

There is no natural line of demarcation between the small colon and rectum: the plane of the pelvic inlet is selected for convenience of description.

Footnote 96:

The anterior part of the rectum is very variable in position and relations. It is not often median, but may be deflected either to right or left. Most often it is pushed to the left by the pelvic flexure of the colon. In other cases—especially when empty—it may lie against the right wall, and the space to the left is occupied by the small colon. The amount covered by peritoneum dorsally and laterally is very variable, and appears to be in inverse proportion to the fullness of the bowel.

Footnote 97:

A descriptive method based on that in use in human anatomy cannot be applied with clearness to the organ in the horse.

Footnote 98:

These impressions are not evident on the soft organ. In hardened material they are clearly mapped out, although of course variable in size, in conformity with the degree of fullness of the various hollow viscera. The cæcal impression may not be evident if, as often happens in old horses, the right lobe of the liver is much atrophied.

Footnote 99: