54 ANATOMY. 



they possessed in their youth ; and that their feet, like other 

 parts of the body, are subject to disease from various causes. 

 Even in a state of unrestrained freedom, horses are found with 

 diseased feet, that have never been shod. 



The different parts that form the foot will now be noticed. 

 By referring to the plate, figure d, a section of the coffin 

 bone, will be seen, where, while it somewhat resembles the 

 foot in shape, it contains the two principle arteries which 

 supply the foot. They enter the lower and back part of the 

 bone, immediately under and behind the termination of the 

 flexor tendon. The arteries give off several branches within 

 the coffin bone, which pass out through orifices at its lower 

 and front part, to be distributed over its surface. The coffin 

 bone is connected with the coronary, or small pastern, and 

 with the navicular, (figure e,) or nut bone. At the posterior, 

 or back part, the flexor tendon (figure n) is inserted into the 

 coffin bone. 



The nut, or navicular bone, (figure e,) is in shape not un- 

 like a boat. It is interposed between the flexor tendon and 

 other bones, to remove the insertion of the tendon farther 

 from the centre of motion ; having a polished surface con- 

 stantly moistened by a fluid resembling synovia, or joint oil. 



The coronary, or small pastern bone, rests both on the coffin 

 bone and navicula, to which it is firmly united by ligaments. 



The great pastern, or os suffraginis, rests on the small 

 pastern, and is also firmly united by ligaments. The two 

 sessamoid bones are placed at the upper and posterior part of 

 the large pastern, to which they have a strong ligamentous 

 attachment. 



The canon, or shank bone, (figure a,) rests both on the great 

 pastern and sessamoid bones. It articulates and moves easily 

 upon them. 



There are two elastic bodies attached to the upper and 

 lateral edge of the coffin bone. They are named lateral car- 

 tilages ; they occupy all the space between the extensor ten- 

 don and the back part of the sensitive frog. The lower 

 part of these cartilages is covered by the hoof. The elastic 



