39° NERVOUS SYSTEM. 
surface of the sixth and seventh nerves (Fig. 159, 7). It passes 
toward the shoulder-joint and supplies the biceps (Fig. 160, 4) 
and coracobrachialis muscles. It then passes distad, resting on 
the dorsal border of the biceps (4), and supplies the brachialis 
muscle. Thence it passes dorsad of the biceps to the lateral 
side, and reaches the integument by passing between the clavo- 
brachialis and pectoantibrachialis muscles near the elbow; it is 
then distributed to the skin on the radial side of the ventral sur- 
face of the forearm, as far as the wrist (Fig. 130, 7, page 319). 
8. N. cutaneus medialis (Fig. 160, 0).—The medial (or 
internal) cutaneous nerve rises from the first thoracic. It 
passes distad along the medial side of the biceps, and at the 
junction of the second and third thirds of the upper arm reaches 
the integument by passing between the epitrochlearis and 
pectoantibrachialis muscles. It then curves spirally about the 
dorsal border of the forearm and is distributed to the integu- 
ment of the forearm on the ulnar side, extending nearly to the 
wrist. 
g. N. medianus (Fig. 160, ¢).—The median nerve is 
formed by the junction of three branches, one each from the 
seventh and eighth cervical with the brachial artery (g) passing 
between them, and one from the first thoracic nerve. It 
accompanies the brachial artery (g) lying on its medial side, 
and passes with it through the supracondyloid foramen; here 
it is connected by a branch to the musculocutaneous nerve. 
It passes into the forearm (Fig 161, 4), lying at first beneath 
the pronator teres (5). Here it gives branches to the pronator 
teres and flexor muscles (flexor carpi radialis, palmaris longus, 
five heads of the flexor profundus digitorum, but oz to the 
flexor carpi ulnaris). Continuing along the forearm, lying on the 
flexor carpi radialis, it sends a posterior interosseous nerve to 
the pronator quadratus muscle and branches to the deep and 
superficial divisions of the flexor sublimis digitorum. It thus 
supplies the flexor and pronator muscles (except the flexor 
carpiulnaris). It then passes into the palm beneath the trans- 
verse ligament and gives rise to three principal branches. The 
first of these supplies the integument of the thumb, sending a 
branch on either side of it; and onto the radial side of the 
