106 ANATOMY OF THE DOMESTIC FOWL 



portion from the tubercle found above the oblique trochlear facet 

 of the distal end of the radius. 



Insertion. Becoming a flat, broad, and strong tendon at about the 

 middle of the forearm, finally becomes inserted to the apex of the 

 anchylosed first metacarpal of the carpo-metacarpus. 



Shape. A thick, fusiform belly, tendinous at both extremities. 



Relations. By the side of the pronator brevis. 



Action. Raises the hand, and draws it forward toward the radial 

 margin of the forearm and retains it on the same side. 



Extensor Digitorum Communis (Fig. 15, No. 2). Location. The 

 upper metacarpal region. 



Origin. Immediately below the tubercle of the external condyle 

 of the humerus. 



Insertion. By a small tendon to the outer side of the base of the 

 pollex, and at a mid-point upon the anterior rim of the proximal 

 phalanx of the middle finger. 



Shape. Small spindle-shaped, becoming tendinous at about the 

 middle of the forearm. 



Relations. Occupies the middle of the group of muscles on the 

 outer side of the forearm. 



Action. An extensor of the digit. 



Supinator Brevis (Fig. 14, No. 7). Location. The superior part 

 of the radius. 



Origin. From the external condyle of the humerus below the 

 origin of the tendon of the extensor digitorum communis. 



Insertion. To the outer side of the shaft of the radius, for nearly 

 one-third of its length. 



Shape. Thin, slender. , 



Relations. Inferiorly, with the bone. 



Action. A supinator of the radial region, and antagonistic to the 

 pronators. 



Flexor Metacarpi Radialis (Fig. 15, No. 10). Location. The low- 

 est of the group of three muscles on the outer part of the forearm. 



Origin. By two tendinous heads, the longer from the external 

 condyle of the humerus, and the other just beyond the base of the 

 olecranon. 



Insertion. Becomes tendinous at about the middle of the shaft 

 of the ulna and inserts to a prominent. process on the proximal 

 third of the posterior part of the shaft of the mid-metacarpal. 



Shape. Fusiform. 



