THE MEDIAN NERVE IN THE HAND. 73 



phalangeal articulations from small arterial arches on the bones, 

 an arch being close above each joint. On the dorsum of the last 

 phalanx is a plexus from which the nail pulp is supplied. 



PALMAR PART OF THE ULNAR NERVE (fig. 27, i). The ulnar Ulnar nerve 

 nerve, like the artery, divides, on or near the annular ligament, into m the hand 

 a superficial and a deep part. 



The deep part accompanies the deep branch of the artery to the divides into 

 muscles, and will be dissected with that vessel (fig. 31). Jeep and 



The superficial part furnishes an offset to the palmaris brevis superficial 

 muscle, and some filaments to the integument of the inner part of parts ' 

 the hand, and ends in two digital nerves for the supply of both 

 sides of the little finger and half the next. 



Digital nerves ( 2 ). The more- internal nerve is undivided, like Digital 

 the corresponding artery. two. 



The other is directed to the cleft between the ring and little 

 fingers, and bifurcates for the supply, of their opposed sides ; in the 

 palm of the hand this branch is coiihected with an offset ( 5 ) of the 

 median nerve. 



Along the sides of the fingers the digital branches have the same 

 arrangement as those of the median nerve. 



PALMAR PART OF THE MEDIAN NERVE (fig. 27, 3 ). As soon as the Median 

 median nerve issues from beneath the annular ligament it becomes 

 enlarged and somewhat flattened, and divides into two nearly equal 

 parts for the supply of digital nerves to the thumb and the remain- 

 ing two fingers and a half ; the outer part also furnishes a small 

 muscular branch to the ball of the thumb. The branches of the 

 nerve are covered by the fascia and the superficial palmar arch ; 

 and beneath them are the tendons of the flexor muscles. 



a. The muscular branch ( 4 ) supplies the flexor brevis, the Branch to 

 abductor, and the opponens pollicis muscles. 



b. The digital nerves ( 5 ) are five in number. Three of them are Five digital 

 undivided, and come from the external of the two pieces into which ne 



the trunk of the median splits. The other two spring from the 

 inner piece of the nerve, and are bifurcated, each supplying the 

 opposed sides of two fingers. 



The first two nerves belong to the thumb, one on each side, and first two, 

 the outer one communicates with a branch of the radial nerve. 



The third is directed to the radial side of the index finger, and third, 

 gives a branch to the most external lumbrical muscle. 



The fourth furnishes a nerve to the second lumbrical muscle, and fourth, 

 divides to supply the contiguous sides of the fore and middle 

 fingers. 



The fifth also divides into two branches, which are distributed to fifth, 

 the opposed sides of the middle and ring fingers ; it communicates 

 with a branch of the ulnar nerve. 



On the fingers. On the sides of the fingers the nerves are in front On the sides 

 of the arteries, and reach to the last phalanx, where they end in 

 filaments for the ball, and the pulp beneath the nail. In their 

 course downwards the nerves supply chiefly tegumentary branches, lateral 

 One of these (the dwsal branch) is directed backwards by the side of onsets. 



