THE MUSCLES OF THE UPPER EXTREMITY. 



121 



insert itself into the entire under surface of the ole- 

 cranon process of the ulna, 



The triceps is the great extensor of the antibrachium, 

 and direct antagonist of the brachialis anticus and 

 })icaps. Its scapula or long head also materially pro- 

 tects that part of the shoulder-joint over which it passes, 



FIG. 36. Bones of the forearm and hand of a Raven ; palmar aspect, and slightly 

 dislodged from their normal positions in order the better to show the 

 origins and insertions of muscles for which the drawing is designed. 

 Life-size, by the author, from a specimen in his own collection. 



and assists other muscles of that region in retaining the 

 humerus in its shallow socket. 



72. The brachialis anticus is a very well-defined and 

 neat little muscle in the Eaven (Figs. 24, 29, and 37). It 

 arises almost entirely fleshy from a circumscribed area on 

 the inner side of the anconal aspect of the distal extremity 



