35 



Below the knee is the cannon bone (r), which articulates at its upper 

 extremity with the lower row of the bones of the knee and at the other 

 end with the upper pastern. It is the the principal bone of this portion 

 of the leg and almost entirely devoid of any muscular covering', those 

 parts of it which are not hidden by tendons, being only protected by 

 skin. This bone is nearly straight, rounded in front, and flattened or 

 slightly concave behind. 



The splint bones (s), are situated behind the cannon and a little on 

 each side of it. Throughout their length they are united by cartilage 

 and ligaments to the cannon bone. 



The next two bones are the upper (w), and lower (v), pasterns. They 

 have considerable motion on one another to allow the foot to be bent 

 back. 



Behind the fetlock joint, -which unites the cannon bone with the 

 upper pastern are two supplementary bones, termed sesamoids (t), they 

 serve to protect the back of the joint and some important ligaments 

 passing over it. 



The toe is formed by the coffin bone (w), which is surrounded by the 

 horny hoof. Another small bone called the navicular (x), is found be- 

 hind and partly within the junction of the coffin and lower pastern, and 

 like the former bone is enclosed by the hoof. 



Beginning at the upper extremity of the hind limb, the first bone to 

 be noticed is the femur (j>), or upper bone of the thigh. It is exceeding- 

 ly strong and stout ; it is short for its bulk, which is further augment- 

 ed by several large projections or trochanters placed lengthwise for the 

 attachment of some important muscles. The upper extremity of the 

 femur has a distinct rounded head, on the inner side fitting into, and 

 articulating with the acetabulum or bonyc up formed at the junction of 

 the three pelvic bones. But the lower end of the bone bears two prom, 

 inences, which fit into corresponding depressions in the next bone and 

 in front of which is placed the patalla or knee cap, together making up 

 the stifle joint of horsemen, or, more strictly speaking the actual knee 

 of anatomists. 



The thigh consists of two bones, the tibia (a"), and the fibula (£")• 

 The tibia extends from the stifle joint to the hock. The fibula is placed 

 behind the outer side of it, extending from its upper extremity to about 

 one third of its length. It is attached to the larger bone by cartilage 

 and in general character agrees with the ulna of the front leg. 



The hock (c"-h"), is an important and somewhat complicated joint. 

 It corresponds with the ankle and heel in man, although in the horse it is 

 at some distance from the ground. lake the carpus, the hock (tarsus) 

 consists of several small bones interposed between the long ones of the 

 lower part of the limb. They are six in number : The os calcis (c"), 

 astragalus (i"), cuboides (/'), navicular (/"), outer cuneiform (A"), mid- 

 dle cuneiform (g"). As the great toe is not represented in the horse, the 

 inner cuneiform is not developed. 



The os calcis or heel bone forms the point of the hock. It acts as a 

 lever to straighten the joint and is moved by the achilles tendon and 



