410 JAMES CRAWFORD WATT 



b. The deep radial nerve, which Ues under the three super- 

 ficial extensor muscles (fig. 10) and on the surface of the supi- 

 nator which is covered in by the others. The nerve supplies all 

 these muscles. 



From the lateral cord 



S. Musculocutaneous nerve. Supplies the coracobrachialis mus- 

 cle and penetrates it (fig. 8, Mc. N.) between its upper and 

 middle portions to pass between the biceps and the preaxial por- 

 tion of the brachialis, supplying both the latter muscles and 

 ending cutaneously in the forearm. 



4. Outer head of the median nerve. The median nerve is 

 described under the inner cord. 



From the inner cord 



5. Inner head of the median nerve. Unites with the lateral 

 head over the axillary artery. 



The median nerve (fig. S, M. N . ) courses ventral and medial 

 to the axillary and brachial arteries in the groove medial to 

 the biceps muscle. It enters the forearm deep to the flexor 

 carpi radialis and superficial head of the flexor digitorum sub- 

 limis, and in front of the biceps tendon and is accompanied by 

 the medial vena comes of the brachial artery, while the artery 

 and the lateral vein lie under the two biceps tendons. As it 

 passes the elbow, it gives branches to the flexor carpi radialis, 

 flexor digitorum sublimis and flexor carpi ulnaris and then 

 divides into a superficial and a deep branch. 



The deep branch evidently is the volar interosseous nerve of 

 the normal arm, and it supplies the three deep muscles arising 

 on the shaft of the radius. 



The superficial branch of the median nerve (figs. 7 and 8, 

 M. N.) comes immediately from under cover of the flexor carpi 

 radialis and courses subcutaneously down the ventral surface of 

 the lower two-thirds of the forearm and over the carpus. In the 

 distal third of the forearm it gives ofT a large cutaneous branch 

 on the medial side. 



