280 



THE EXTERIOR OF THE HORSE. 



Of these three bones, one, the principal metatarsal or metacarpal, is much 

 more developed than the other two, which are altogether rudimentary. The latter 

 (Fig. 92) are united to the sides of the principal bone by means of a very resist- 

 ing interosseous ligament which ossifies with age, save at its two extremities. 



Fig. 92. 



Fig. 113. 



The superior part, or the head of these small styloid bones, is articulated by two 

 diarthrodial facets with the extremity of the median bone of the canon ; their 

 inferior extremity, slightly dilated and button-shaped, almost free and tangible to 

 the finger, is united by a fibrous ligament to the region which we will study as 



the ergot. 



Thus constituted, the canon is articulated above, through the intervention 

 of its component parts, with the lower row of carpal or tarsal bones, from which 

 it receives and transmits impressions ; below, the middle bone forms with the 

 first phalanx a very movable joint, which is completed, behind, by the two sesa- 

 moid bones. 



No muscles worthy of attention exist in this region. The tendons of the 

 extensor muscles of the phalanges are found on its anterior surface, and those of 

 the flexors, perforans, and perforatus on the posterior. We must mention, be- 

 sides, the carpal and the tarsal check tendons, fibrous, unelastic laminae, 

 which emanate from the posterior ligament of the carpus and the tarsus, and ter- 

 minate, after a more or less extensive course, in the deep flexor tendon of the 

 digit. 



Two large synovial membranes exist, one above, the other below, upon about 

 a third of the length of the canon. The superior we have already studied : it 

 belongs to the carpal or the tarsal sheath. The inferior will be studied with the 



