56 



DISSECTION OF FRONT OF FOREARM. 



Subcuta- 

 neous veins 



plexus on 

 the hand ; 



radial ; 



ulnar, 

 anterior 



and poste- 

 rior ; 



median. 



Superficial 

 nerves of 

 forearm 



and back of 

 hand are 



internal 

 cutaneous, 



external 

 cutaneous ; 



nerve ; and lying along the outer border of the hand is the radial 

 nerve : these should be traced to the fingers. 



CUTANEOUS VEINS. The superficial veins are named median, 

 radial, and ulnar, from their position in the limb. 



DORSAL PLEXUS OF THE HAND. This network receives the super- 

 ficial veins from both surfaces of the fingers ; and from it, on the 

 outer and inner sides, the radial and posterior ulnar veins proceed. 



The RADIAL VEIN begins in the outer part of the plexus above 

 mentioned, and in some small radicles at the back of the thumb. 

 It is continued along the forearm, at first behind and then on the 

 outer border as far as the elbow, where it gives rise to the cephalic 

 vein by its union with the outer branch of the median vein (fig. 1 6, 

 p. 40). In many bodies a considerable branch passes from the 

 lower part of the radial vein to join the median vein on the front of 

 the forearm. 



The ULNAR VEINS (fig. 16) are anterior and posterior, and occupy 

 the front and back of the limb. 



The anterior begins near the wrist by the junction of small roots 

 from the hand, and runs on the inner part of the forearm to the 

 elbow, where it opens either into the median-basilic or posterior 

 ulnar vein. 



The posterior ulnar vein arises from the inner part of the dorsal 

 plexus of the hand, and is continued along the back of the forearm 

 nearly to the elbow ; here it bends forward to join the inner branch 

 of the median and form the basilic vein. 



The MEDIAN VEIN takes origin near the wrist by small branches 

 which are derived from the palmar surface of the hand. It is 

 directed along the centre of the forearm nearly to the elbow, and 

 there divides into median-basilic and median-cephalic, which unite, 

 as before seen, with the radial and ulnar veins. At its point of 

 bifurcation the median receives a large communicating branch from 

 the deep veins beneath the fascia. 



CUTANEOUS NERVES (fig. 15, p. 39, and fig. 23, p. 57). Some of 

 the superficial nerves of the forearm are continued from the arm, 

 those on the inner side from the large internal cutaneous nerve and 

 those on the outer from the lower external cutaneous branch of the 

 musculo-spiral and the musculo-cutaneous. On the fore part of the 

 limb there is occasionally a small offset of the ulnar nerve near the 

 wrist. On the back of the hand is the termination of the radial 

 nerve, together with the dorsal branch of the ulnar nerve. 



The INTERNAL CUTANEOUS NERVE (p. 49) is divided into two. 

 The anterior branch extends on the front of the forearm as far as the 

 wrist, and supplies the integuments on the inner half of the anterior 

 surface. Near the wrist it communicates sometimes with a cutaneous 

 offset from the ulnar nerve (fig. 15). The posterior branch continues 

 along the back of the forearm (ulnar side) to the lower part (fig. 23). 



The MUSCULO-CUTANEOUS NERVE (cutaneous part, p. 50) is pro- 

 longed on the radial border of the limb to the ball of the thumb, 

 over which it terminates in cutaneous offsets. Near the wrist the 

 nerve is placed over the radial artery, and some twigs pierce the 



