396 



THE MUSCULATURE 



the lateral surface of the middle third of the shaft of the radius; the fusiform 

 flexor carpi radialis sends a tendon to the base of the second metacarpal; the 

 slender palmaris longus is inserted into the palmar fascia; and the medially 

 situated, fusiform flexor carpi ulnaris into the pisiform bone and the palmar 

 fascia. The pronator teres is the most powerful pronator of the forearm. When 



Fig. 370. — Front of the Fore\rm' Fir«;t Layer of Muscles. 



Triceps 



Brachialis 



Pronator teres 



Flexor carpi radialis 



Palmaris longus 



Flexor carpi ulnaris 



Flexor digitorura sublimis 



Biceps 



Brachio-radialis 



Flexor pollicis longus 



the hand is slightly flexed the ulnar carpal fi(>xor abducts ulnarward. When the 

 hand is greatly flexed hitcral movement is difJicult. The ulnar flexor is supplied 

 by the ulnar nerve, the otlier muscles by tli(> incdiun. 



The pronator teres probably corresponda with (he i)()plitcus of the leg. The flexor carpi 

 radialiH and floxor farpi iilnari.s probably represent in the main the two heads of the gastroc- 

 nemiu.s, and tlic palmaris longus, the plantaris. . , , 



The pronator teres (fig. 'S70j.— Origin.— l^y two heads:— (1) The humeral or chief head 

 ari.ses by a tendon from the superior half of the ventral surface of the medial epicondyle and 

 directly from the overlying fascia and from the intermuscular septa between it and the medial 



