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- 

 siderabljr 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. 



Fig. lol. — Boxes of Distal Part of Foee Limb of 

 C)x; Lateral \'iew. 

 1, Distal end of metacarpal^bone; 2, first phalanx; 

 3, proximal sesamoid bone; 4, second phalanx; 5, ex- 

 tensor process of third phalanx; 6, dorsal surface; 7, 

 angle; S, distal sesamoid bone. 



Fig. 152. — BONE.S OF Dist.al P.^rt of Fore Limb op 

 Ox; Volar \"iew. 

 1, Metacarpal bone; 2, proximal sesamoid bones; 

 3, first phalanx; 4, second phalanx; 5, distal t 

 bone; 6, third phalanx. 



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 concave, 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 



