10 3 THE XELl \ r E ti ) 'HTEM 



arm it is accompanied by the arteria comes nervi median!, a branch of the anterior 

 interosseous artery. 



Branches. With the exception of the nerve to the Pronator feres muscle, which 

 sometimes arises above the elbow-joint, and filaments to the elbow-joint, the 

 median nerve gives off no branches in the arm. In the forearm its branches are 

 the muscular, anterior interosseous, and palmar cutaneous. 



The muscular branches (rami musculares) are derived from the nerve near the 

 elbow and supply all the superficial muscles on the front of the forearm except 

 the Flexor carpi ulnaris. 



The anterior or volar interosseous (//. interosseus [antebrachii] volaris} (Fig. 7(14) 

 supplies the deep muscles on the front of the forearm, except the inner half of the 

 Flexor profundus digitorum. It accompanies the anterior interosseous artery 

 along the interosseous membrane, in the interval between the Flexor longus 

 pollicis and Flexor profundus digitorum muscles, both of which it supplies, and 

 terminates below in the Pronator quadra tus muscle, sending filaments to the 

 inferior radioulnar articulation and the wrist-joint. 



The palmar cutaneous branch (ramus cutaneus palmaris n. mediani) arises from 

 the median nerve at the lower part of the forearm. It pierces the fascia above 

 the annular ligament, and, descending over that ligament, divides into two branches, 

 of which the outer branch supplies the skin over the ball of the thumb, and com- 

 municates with the anterior cutaneous branch of the musculocutaneous nerve; 

 and the inner branch supplies the integument of the palm of the hand, communi- 

 cating with the cutaneous branch of the ulnar. 



In the palm of the hand the median nerve is covered by the integument and 

 palmar fascia and is crossed by the superficial palmar arch. It rests upon the 

 tendons of the flexor muscles. In this situation it becomes enlarged, somewhat 

 flattened, of a reddish color, and divides into two branches. Of these, the external 

 branch supplies a muscular branch to some of the muscles of the thumb and 

 digital branches to the thumb and radial side of the index finger; the internal 

 branch supplies digital branches to the contiguous sides of the index and middle 

 and of the middle and ring fingers. The digital branches, before they subdivide, 

 are called common palmar digital branches of the median nerve (////. digitales volarex 

 communes). 



The branch to the muscles of the thumb (ramus muculari:i) is a short nerve which 

 divides to supply the Abductor, Opponens, and the superficial head of the Flexor 

 brevis pollicis muscles, the remaining muscles of this group being supplied by 

 the ulnar nerve. 



The digital branches (mi-, digitales volares proprii) are five in number. The 

 first and second pass along the borders of the thumb, the external branch communi- 

 cating with branches of the radial nerve. The third passes along the radial side 

 of the index finger, and supplies the First lumbricalis muscle. The fourth sub- 

 divides to supply the adjacent sides of the index and middle fingers, and sends 

 a branch to the Second lumbricalis muscle. The fifth supplies the adjacent 

 sides of the middle and ring fingers, and communicates with a branch from the 

 ulnar nerve. 



Pkch digital nerve, opposite the base of the first phalanx, gives off a dorsal branch, 

 which joins the dorsal digital nerve from the radial nerve and runs along the side 

 of the dorsum of the finger, to end in the integument over the last phalanx. At 

 the end of the finger the digital nerve divides into a palmar and a dorsal branch, 

 the former of which supplies the extremity of the finger, and the latter ramifies 

 around and beneath the nail. 



The digital nerves, as they run along the fingers, are placed superficial to the 

 digital arteries. The cutaneous areas supplied by the median nerve are shown 

 in Figs. 762 and 763. 



