THE PASTERNS. 



267 



The upper pastern bone (5, Fig. 37, and a, in Fig, 38, and h, 

 in Fig. 39,) receives the lower pulley-like head of the shank-bone, 

 and forms a hinge-joint admitting only of bending and extension, 

 but not of side motion ; it likewise forms a joint with the sessa- 

 moid-bones. Its lower head has two rounded protuberances, 

 which are received into corresponding depressions in the iowei 

 pastern. On either side, above the pastern-joint, are roughened 

 projections for the attachment of very strong ligaments, both in 

 capsular ligaments, and many cross ligaments, which render the 

 joint between the two pasterns sufficiently secure. 

 Fig. 88. Fig. 89. 



Fig. 38. 

 a The apper paBtern. 

 b The lower pastern. 

 c The navicular hone. 

 d The coflSn-bone. 



Fig. 39. 

 n. The 8essamoid-bone. 

 b The upper pastern, 

 c The lower pastern. 

 d The navicular hone. 

 f The coffin-bone, with the bomylaminss. 



The lower pastern {d, Fig. 37, and b, in the first figure, and c, 

 in the second in this cut,) is a short and thick bone, with its larger 

 Lead downward. Its upper head has two depressions to receive the 



Fig. 40. 



protuberances on the lower head of the upper 

 bone, bearing some resemblance to a puUy, 

 but not so decidedly as the lower head of the 

 shank-bone. Its lower head resembles that 

 of the other pastern, and has also two prom- 

 inences, somewhat resembling a pulley, by 

 which it forms a joint with the coffiin-bone , 

 and a depression in front, corresponding with 

 a projection in the coffin-bone. There are 

 also two slight depressions behind, receiving 

 eminences of the navicular bone. Neither 

 of these joints admits of any lateral motion. 

 The ligaments of this joint, both the capsu- 

 lar and the cross ones, are, like those of the 

 pastern-joint, exceedingly strong. The ten- 

 don of the extensor muscle is inserted into 



