kni;e, f:5Ti<ock, ankle, and foot. 171 



by ligaments of fibrous tissue, and are lubricated by a thick viscid 

 fluid, called synovia, wliich is secreted by a special membrane inclosing 

 the joints. 



Fetlock. This joint is made by the union of the lower end of the 

 cannon and the upper end of the large pastern bones, supplemented by 

 the two sesamoids, so placed behind the upper end of the pastern that 

 the joint is capable of a very extensive motion. These bones are held 

 , together by ligaments, only one of which (the suspensory) demands spe- 

 cial mention. 



Suspensory I/igament. This ligament starts from the knee, ex- 

 tends down behind the cannon, lying between the two splint bones, until 

 near the fetlock, where it divides and sends a branch on either side of 

 the joint, downward and forward, to become attached on the sides of the 

 extensor tendon at the lower end of the pastern bone. As it crosses the 

 sesamoids on the posterior borders of the fetlock it throws out fibers, 

 which hold it fast to these bones. 



Pastern Joint. This is made by the union of the , two pastern 

 bones. 



Coffin Joint. This is made by the union of the small pastern, coffin, 

 and small sesamoid or navicular bones, the latter being set behind and 

 beneath the joint surface of the coffin bone, in such a way as to largely 

 receive the weight of the large pastern. 



Tendons. There are three tendons which serve to move the bones 

 of the foot one on another. Two of these bend the joints, while the 

 other extends or straightens the column bones. 



Flexor Pedis Perforans. This is the deep flexor of the foot, 

 passes down behind the cannon bone, lying against the suspensory liga- 

 ment in front, crosses the fetlock joint in the groove made by the union 

 of the two sesamoids, and is attached to the bottom of the coffin bone, 

 after covering the navicular, by a wide expansion of its fibers. It is 

 the function of this tendon to flex the coffin bone and with it the 

 horny box. 



Flexor Pedis Perforatus. This is the superficial flexor of the 

 foot and follows the course of the preceding tendon, and is attached to the 

 middle of the ankle. The function of this tendon is to bend the foot at 

 the fetlock. 



Bxtensor Pedis. This runs down the front of the leg and is at- 

 tached on the most prominent point of the coffin bone, and has for it3 

 function the straightening of the bones of the ankle and foot. 



