SHOULDER, ARM, FOREARM, AND HAND. 



181 



the origin of the flexor longus pollicis muscle ; (4) the origin of the flexor pro- 

 fundus digitorum ; (5) the anterior interosseous artery and nerve on the inter- 

 osseous membrane, but lying deeply between two muscles the flexor profundus 

 digitorum and the flexor longus pollicis. 



The Median Nerve and its Branches. Take the nerve up, and you can 

 easily trace muscular branches with the forceps to all the muscles on the front 



Pectoralis minor 



Coraco-brachialis 



Long head of triceps 



Inner head of triceps 



Brachialis anticua 



Semilunar fascia 



Tendons of insertion of pec- 

 toralis major and deltoid 



Outer head ct triceps 



- Brachialis anticua 



Extensor carpi radialis 

 longior 



Brachi o -rad i alis 



FIG. 126. SUPERFICIAL VIEW OK THE FRONT OK THE UPPER ARM. 



part of the forearm except the flexor carpi ulnaris and half of the flexor profundus 

 digitorum muscles ; the flexor carpi ulnaris and the ulnar half of the flexor 

 profundus digitorum muscles are supplied by the ulnar nerve. You will observe 

 that some of the branches of this nerve are given off above the articulation. 

 (Fig. 123.) Remember, the shape of a muscle is an index to nerve distribution. 

 See introductory chapter. 



