150 SKELETON OF THE OX 
tinctly three-sided. The proximal articular surface is divided by a sagittal ridge 
into two glenoid cavities, of which the abaxial one is much the larger. There is a 
central dorsal prominence and two tubercles are present on the volar face. The 
distal extremity is smaller than the proximal. Its articular surface encroaches con- 
siderably on the dorsal and volar surfaces, and is divided into two parts by a 
sagittal groove. There is a deep depression for ligamentous attachment on the inter- 
digital side. The bone contains a small medullary canal. The distal end unites 
with the rest of the bone about the middle of the second year. 
The third phalanges resemble in a general way one-half of the bone of the horse. 
Each has four surfaces. The dorsal surface is marked in its distal part by a shal- 
low groove, along which there are several foramina of considerable size; the 
posterior one of the series is the largest, and conducts to a canal in the interior of 
the bone. Distal to the groove the surface is prominent, rough, and porous. 
Fic. 151.—Bones or Distat Part or Fore Live or Fia. 152.—Boners oF DistaL Part or Fors Limp oF 
Ox; LaTerRAL VIEW. Ox; Vouar VIEW. 
1, Distal end of metacarpal bone; 2, first phalanx; 1, Metacarpal bone; 2, proximal sesamoid bones; 
3, proximal sesamoid bone; 4, second phalanx; 5, ex- 3, first phalanx; 4, second phalanx; 5, distal sesamoid 
tensor process of third phalanx; 6, dorsal surface; 7, bone; 6, third phalanx. 
angle; 8, distal sesamoid bone. 
Near and on the extensor process are several relatively large foramina. The slope 
of the surface is very steep posteriorly, but in front it forms an angle of 25 to 30 de- 
grees with the ground plane. The articular surface is narrow from side to side, and 
slopes downward and backward. It is also oblique transversely, the interdigital 
side being the lower. It is adapted to the distal surface of the second phalanx, with 
the exception of a facet behind for the distal sesamoid. The extensor process is 
very rough. The volar surface is narrow and slightly coneave, and presents two 
or three foramina of considerable size. It is separated from the dorsal surface 
by a border which is sharp in front, rounded behind. There is no semilunar crest, 
since the deep flexor tendon is attached to the thick posterior border of the volar 
surface. The interdigital surface is smooth and grooved below, rough and porous 
above. At the proximal angle it is perforated by a large foramen, which is equiva- 
lent to the volar foramen of the horse and leads to a cavity in the middle of the bone. 
The surface is separated by a rounded border from the dorsal surface, and by a sharp 
