THE ULNA 49 



clips, and eyelets through which a strap or band secures it ; it is shaped 

 to the posterior contour of the limb, and, passing upwards, it is pierced 

 by a number of slits or slots for straps by which to attach it to the limb. 

 At its upper part it branches forwards into an expanded portion which 

 embraces the elbow. This piece may be movable on each side, and, by 

 means of screws, be made to compress the upper part of the arm as 

 tightly as necessary ; there are slits on each side for straps to fasten 

 it round the forearm." A plentiful supply of padding should be 

 introduced between the limb and the splint. 



THE ULNA 



A remarkable feature of this bone in the horse is its relatively small 

 size. In most other animals it is much longer even than the radius, and 

 the two bones are frequently movably articulated. It has already been 

 stated that in the horse the bones are firmly ossified to one another. 



It is a long bone, the development of which has been arrested, and it 

 has another peculiarity as a long bone in being destitute of a medullary 

 canal. 



The ulna possesses a body and an olecranon process. The body pos- 

 sesses an anterior and two lateral surfaces. The anterior surface presents 

 an elongated triangular area, the apex of which extends to the inferior 

 extremity of the bone. This part of the bone is attached to the similar 

 area described when dealing with the back of the radius. Above this 

 area is a depression which completes, with the similar depression on the 

 radius, the radio-ulnar arch. Above the radio-ulnar arch again we have 

 two small facets for articulation with the facets on the radius, and a small 

 roughened area affording the other attachment to the second interosseous 

 ligament described. The lateral surfaces of the body are smooth and 

 slightly convex, and are separated from one another by the posterior edge 

 of the bone, which is smooth and rounded. Above the radio-ulnar arch 



G 



