BRANCHES OF THE MEDIAN NERVE. 591 



nlnaris and part of the deep flexor of the fingers, are supplied from 

 this nerve. 



a. The branches, for the superficial muscles are separate twigs given off from 

 the nerve below or near the elbow-joint, but the branch furnished to the pronator 

 teres often arises above the joint. 



h. Anterior infcrtm.'^eou.i iirrvc. — This is the longest branch of the median 

 nerve, and it supi^lies the deeper muscles of the forearm. Commencing at the 

 upper part of the forearm, beneath the superficial flexor of the fingers, it passes 

 downwards with the anterior interosseous arterj- on the interosseous membrane, 

 and between the long flexor of the thumb and the deep flexor of the fingers, to 

 the pronator quadratus muscle, in which it ends. 



c. The cvi a neovs palmar branch pierces the fascia of the forearm close to the 

 annular ligament, and descending over that ligament, ends in the integument of 

 the palm about the middle : being connected by a twig with the cutaneous 

 ' palmar branch of the ulnar nerve. It distributes some filaments over the ball 

 of the thumb, which commmiicate with twigs of the radial or the external cuta- 

 neous nerve. 



B. Branches in the hand : — 



a. Branch tomvsclcs oj the thvn'b. — This short nerve subdivides into branches 

 for the abductor, the opponens, and the outer head of the flexor brevis pollicis 

 muscle. 



h. Digital nerva. — These are five in number, and belong to the thumb, and 

 the fingers as far as the outer side of the ring-finger. As they approach the 

 clefts between the fingers, they are close to the integument in the intervals 

 between the longitudinal divisions of the palmar fascia. 



Th.Qfird and .second nerves lie along the sides of the thumb ; and the former 

 (the outer one) is connected with the radial nerve ixpon the liall of the thumb. 



The f/(!i;YZ destined for the radial side of the index finger, gives a muscular 

 branch to the first or most external lumbricalis muscle. 



The/<3?;/'r/i supplies the second lumbricalis, and divides into branches for the 

 adjacent sides of the index and middle fingers. 



The f/th, the most internal of the digital nerves, is connected by a crossing- 

 twig with the ulnar nerve, and divides to furnish branches to the adjacent sides 

 of the ring and middle fingers. 



Fig. 362*. — DisTRiDUTiON OP THE DIGITAL Nerves {from Hirsclifeld and v;„ <3fio«- 

 LeveiUe). i ^' ^^"^ ' 



1, isalmar collatei'al nerve ; 2, its final palmar distribution ; 3, its 

 dorsal or ungual distribution, and between these numbers the network of 

 terminal filaments ; 4, collateral dorsal nerve ; 5, uniting twigs passing 

 between the dorsal and palmar digital nerves. 



Each digital nei"ve divides at the end of the finger into two 

 branches, one of which supplies the ball on the fore part of the 

 finger ; the other ramifies in the pulp beneath the nail. Branches 

 pass from each nerve forwards and backwards to the integimient 

 of the finger ; and one larger than the rest incluies backwards by 

 the side of the first phalanx of the finger, and, after joining the 

 dorsal digital nerve, ends in the integument over the last phalanx, 



SuMJiARY. — The median nerve gives cutaneous branches 

 to the palm, and to three and a half fingers. It supplies 

 the pronator muscles, the flexors of the carpus and the 

 long flexors of the fingers (except the ulnar flexor of the carpus, and 

 part of the deep flexor of the fingers), likewise the outer set of the 

 short muscles of the thumb, and two.lumbricales. 



