274 DISSECTION OF THE HAND. 



the integuments and the palmar fascia, but at the inner border of the hand 

 the palmaris brevis muscle (ii) lies over it. Beneath it are the flexor 

 tendons and the branches of the ulnar and median nerves. Venae cornites 

 lie on its sides. 



Branches. From the convexity of the arch proceed the digital arteries, 

 and from the concavity some small offsets to the palm of the hand. A 

 small branch (profunda) arises as soon as the artery enters the hand. 



a. The profunda or communicating branch (fig. 84, ft), passes down- 

 wards with a branch of the ulnar nerve between the abductor and short 

 flexor muscles of the little finger, to inosculate with the deep palmar arch 

 of the radial artery. 



b. The digital branches (g) are four in number, and supply both sides of 

 the three inner fingers and one side of the index finger. The branch to 

 the inner side of the hand and little finger is undivided ; but the others, 

 corresponding with the three inner interosseous spaces, bifurcate anteriorly 

 to supply the contiguous sides of the above said digits. In the hand these 

 branches are accompanied by the digital nerves, which they sometimes 

 pierce. 



Near the root of the fingers they receive communicating branches from 

 offsets of the deep arch ; but the digital artery of the inner side of the 

 little finger has its communicating branch about the middle of the hand. 



From the point of bifurcation the branches extend along the sides ot 

 the fingers ; and over the last phalanx the vessels of opposite sides unite 

 in an arch, from whose convexity offsets proceed to supply the ball of the 

 finger. Collateral offsets are furnished to the finger and the sheath of the 

 tendons ; and small twigs are supplied to the phalangeal articulations from 

 small arterial arches on the bones an arch being close behind each joint. 

 On the dorsum of the last phalanx is another arch near the nail, from 

 which the nail-pulp is supplied. 



PALMAR PART OF THE ULNAR NERVE (fig. 83, 1 ). The ulnar nerve 

 divides on or near the annular ligament, into a superficial and a deep 

 branch. 



The deep branch accompanies the profunda artery to the muscles, and 

 will be subsequently dissected with that vessel (fig. 84). 



The stiperficial branch furnishes an offset to the palmaris brevis muscle, 

 and some filaments to the integument of the inner part of 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 the cor- 

 responding artery. 



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 last branch is connected 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. 83, 3 ). As soon as the 

 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 remaining two fingers ;m<l 

 a half: the more external of the two portions furnishes a small muscular 

 branch to the ball of the thumb. The trunk of the nerve and its branches 

 are covered by the palmar fascia ; and beneath them are the tendons of 

 the flexor muscles. 



