416 



STRUCTURE AND FUNCTIONS OF THE OX S FOOT. 



surfaces, which meet in front, are of a more triangular form. 

 The upper articular surface of each coronet bone is concave, 

 the lower is convex, and extends almost as far backwards as 

 the middle of the posterior surface. 



The third phalanx, or bone of the claw, however, differs 

 markedly from the horse's pedal bone. The claw bone is 

 peculiarly formed, having been compared to a wedge or three- 

 sided pyramid, the point of which is directed forwards and 

 downwards. Each claw bone presents an upper or articular 

 surface, an outer turned away from the cleft of the hoof, au 

 inner turned towards it, a lower surface, an anterior and a 

 posterior end, and three margins. The articular surface is 



Fig. 397. — Antero-external view of ox's left fore-foot. 1, lower eud of metacarpal bone ; 

 2, external sesamoid bone; 3, external, and 3', internal pastern bone; 4, external, and 

 4' internal coronet bone ; 5, external, and 5', internal claw bone ; 6, left navicular bone. 



concave and extends forwards and upwards as the pyramidal 

 process. The outer surface is slightly convex, with numerous 

 small apertures and with a flat groove or furrow running from 

 behind forwards. The slightly concave inner surface exhibits 

 at its upper posterior part a large aperture, corresponding to 

 the plantar foramen (see p. 29), and extending into the 

 interior of the bone. The lower surface slopes away from the 

 cleft of the hoof towards the outside. It is comparatively 

 smooth and provided on its lower part with a shallow groove. 

 The anterior margin formed by the union of the outer and 

 inner surfaces is blunt, the outer margin sharp and curved, the 



