BOXES OF THE LEG. 357 



head, forming part of the surface on which the lower knee- 

 bones rest. It extends one-half, or a little over, down the 

 shank, and is attached to it by cartilage. 



The sesamoid-bones are two small bones placed at the back 

 part of the pastern- joint, and giving the prominence of the fet- 

 lock. Their object is to strengthen the joint and give attach- 

 ment and protection to the ligaments about the pastern. They 

 enable the tendons passing over the back part of the joint to 

 act with much greater power. Several ligaments are attached 

 to them. (For a more full account of their anatomy and uses 

 see the article on " The Foot.") 



The pastern-hone is about one-third the length of the shank. 

 It is somewhat flat, being rounded and smooth before, and flat 

 and rough behind. Its upper head is the larger, and is marked 

 by a groove and two surfoces corresponding with the lower end 

 of the cannon-bone, with which it forms the pastern-joint. The 

 lower head is the smaller, and convex or oval, and marked 

 from before backward by a slight groove. It is thus di- 

 vided into two oval surfaces to articulate with the next bone 

 below it. 



The pastern sets obliquely forward. Its length and the de- 

 gree of its slant differ very greatly in different breeds and 

 different horses. A pastern of good length and considerable 

 obliquity is indispensable to easy action. It is the only form 

 fit for the riding horse. It alone can long endure quick action. 

 The more upright pastern can not withstand the concussion 

 of rapid action. The horse of heavy draught should have a 

 more upright and shorter pastern. 



The coronet-bone, or hwer ixistern, is an irregularly square 

 bone situated below the pastern-bone. It is broader than long. 

 Its upper surface, or face, is hollowed out at each side to articu- 

 late with the lower end of the pastern-bone. It has a consid- 

 erable projection back of the joint to which is attached part of 

 the ligament. Its lower face is oval, to unite with the coffin 

 and shuttle bones. 



