THE FOREARM. 



307 



bones and blends with the capsules of the metacarpophalangeal joints. It is an 

 additional perforated flexor muscle (Fig. 322). 



i. The flexor profundus digitorum is composed of four slips, one for each 

 finger, and the flexor longus pollicis (Fig. 323) is a fifth slip that supplies the 



Brachioradialis 



Extensor carpi radialis longior 

 Extensor carpi radialis brevior 



Pronator radii teres 



Flexor carpi radialis 

 Palmaris longus 

 Flexor carpi ulnaris 



Flexor longus pollicis 



Pronator quadratus 



Stump of flexor carpi radialis 



Flexor sublimis digitorum 



Flexor sublimis digitorum 



Flexor profundus digitorum 



Flexor carpi ulnaris 



Palmaris longus and palm 

 "ascia turned down 



FIG. 323. Dissection showing the muscles of the forearm, especially the long flexor muscles of the fingers. 



thumb. The flexor profundus arises from the anterior surface of the ulna and inter- 

 osseous membrane while the flexor longus pollicis arises from the anterior surface of 

 the radius and interosseous membrane. Their tendons pass through slits in the 

 flexor sublimis digitorum opposite the proximal phalanges to insert into the bases of 

 the distal phalanges. 



