SOLIPEDA. 



719 



seen in the figure) ; the os magnum (2.) ; and 

 the unci/orme (3.) are all of them readily 

 identified. 



Fig. 498. 



Osteology of tlie. Horse Bones of the anterior 

 Extremity. 



Scapula. h, its neck ; , spine ; k, coracoid apo- 

 physis ; I, /, inferior costa ; m, m, superior costa ; n, n, 

 base ; o, fossa subspinalis ; p, fossa supra-spinalis. 



Os humeri. a, shaft of the bone ; b, protuberance 

 into which the teres major is inserted; e, bicipital 

 protuberance ; /, neck of the hunierus ; t, external 

 condyle ; K, double articular suface, articulated with 

 the radius ; k, internal condyle ; /, anterior fossa which 

 receives the upper head of the radius, when the fore- 

 ami is bent ; m, posterior sinus, for the reception of 

 the olecranon of the ulna, when the fore-arm is ex- 

 tended. 



Radius. n, its upper head ; o, protuberance for 

 the insertion of the tendon of the biceps; r, its 

 lower extremity. 



Ulna. s, the olecranon process ; t, its articulation 

 with the humerus ; u, continuation of the bone which 

 in aged horses becomes united with the radius. 



Bones of the carpus. w, Scaphoides ; x, Lunare ; y, 

 Cuneiforme; z, Pisiforme or Orbiculare; 2, Os 

 magnum ; 3, Unciforme, 



Metacarpus. 4, 5. The great metacarpal or 

 cannon bone. 6, 7. Rudimentary external metacar- 

 pal bone. 10, 11. Sesamoid bones. 



Fore-foot. 12, 13. Pronimal phalanx or great 

 pastern bone, 14, 15. Middle phalanx or lesser 

 pastern or coronary bone. 16. Terminal phalanx 

 or coffin-bone. 17. Sesamoid bone. 



The metacarpal tones are in the horse con- 

 solidated into one large piece, called by farriers 

 the shank or cannon hone, and two smaller 

 supplementary pieces, which seem merely ap- 

 pendages to the former. 



The large cannon bone '(./?#. 498, 4, 5.) is 

 formed by the union of two metacarpal bones 

 indissolubly conjoined, viz. of those which 

 support the ring and middle fingers in the 

 human hand ; these conjoined, here form a 

 massive piece, the upper end of which articu- 

 lates with the carpus, while its distal ex- 

 tremity sustains the first joint of the foot, 



A seconder supplemental piece (JigA98. 6,7.) 

 is simply a rudiment representing the internal 

 metacarpal bone of the human skeleton, or 

 that which in man supports the little finger ; 

 superiorly this piece presents an articulating 

 surface, which articulates with the unciform 

 bone of the carpus, but inferiorly, there being 

 no finger for it to support, it gradually 

 dwindles away to a mere splint, which is ap- 

 plied against the ulnar aspect of the preceding 

 fcone. 



The third bone of the metacarpus is equally 

 rudimentary as the last, and consists of a 

 similar styliform bone applied against the op- 

 posite side of the shank bone, and obviously 

 representing the metacarpal bone of the fore 

 finger. 



The fore foot of the horse is composed of 

 three bones, representing the first, second, and 

 third phalanges in the fingers of the human 

 hand ; but extraordinarily changed in their 

 appearance. Of these, the first (/g. 498. 12, 

 13) is equivalent to the bones of the first 

 phalanges of the ring and middle fingers in 

 the human subject, as is indicated by a central 

 groove, showing this piece to be composed of 

 two lateral halves this bone in the horse is 

 called the "great pastern" 



The second piece (jg. 498. 14. 15.) corre- 

 sponding with the second phalanx, is named, 

 in common language the " little pastern," while 

 the third (16), the representative of the third 

 phalanx, a bone of very large size and cres- 

 centic shape, has received from farriers the 

 name of the " coffin bone" 



In addition to the above may be noticed 

 two sesamoid bones (10, 11) implanted in the 

 flexor tendon of the foot, as it passes behind 

 the articulation between the cannon bone and 

 the great pastern, and a third lying over the 

 posterior part of the articulation, between the 

 coffin bone with the coronary bone, or be- 

 tween the two distal phalanges. 



Posterior extremity. The pelvis of the so- 

 lipeds, both in its disposition and in the shape 

 of the bones composing it, differs in many 

 important particulars from that of man, and 

 even of the generality of quadrupeds. The 

 body of the ileum is elongated into a sort of 



