98 THE UPPER EXTREMITY 



Dissection. With the exception of the palmar cutaneous nerves, the 

 superficial veins and nerves on the volar aspect of the forearm may now be 

 turned aside. The deep fascia should also be removed, and when it is 

 followed round the medial border of the forearm it will be found to be 

 firmly attached to the dorsal border of the ulna. Near the elbow, as 

 already stated, it gives origin by its deep surface to the group of muscles 

 which spring from the medial epicondyle of the humerus. Where this is 

 the case, it should be left in situ. Attempts to dissect it off will only 

 result in laceration of the surface of the subjacent fleshy bellies. The 

 radial artery should be followed out before the muscles are much disturbed, 

 and at the same time the various muscles, covering the volar surface of 

 the radius, and upon which the vessel rests, should be cleaned. 



Arteria Radialis (Radial Artery). The radial artery is 

 the smaller of the two terminal branches of the brachial 

 artery, but its direction gives it the appearance of being the 

 continuation of the parent trunk into the forearm. It takes 

 origin in the fossa cubitalis, opposite the neck of the radius, 

 and it proceeds downwards, along the lateral side of the volar 

 aspect of the limb, until it reaches the distal end of the bone. 

 There it turns round the lateral border of the wrist and leaves 

 the present dissection. At first it lies between the pronator 

 teres and the brachioradialis, and is overlapped to some 

 extent on the lateral side by the fleshy belly of the latter 

 muscle (Fig. 41). Lower down it is placed between the 

 brachioradialis on the lateral side and the flexor carpi 

 radialis upon the medial side, and this position it maintains as 

 far as the wrist. Where these muscles are fleshy the artery 

 lies at some depth from the surface; but when the tendons 

 make their appearance it assumes a superficial position, and 

 is merely covered by the integument and fascia. Through- 

 out its whole length it is closely accompanied by the vena 

 comites, and the superficial division of the radial nerve lies 

 along its lateral side in the middle third of the forearm. 

 More proximally, the nerve is separated from the vessel by a 

 slight interval ; whilst distally, the nerve leaves the artery and 

 turns round the lateral margin of the forearm under cover 

 of the brachioradialis. 



Posteriorly the radial artery is supported by the muscles 

 which clothe and find attachment to the volar surface of the 

 radius. At its origin it rests upon the tendon of the biceps 

 brachii ; next it lies in front of the supinator with some adipose 

 tissue intervening ; thence distally it is in contact with the 

 pronator teres, the thin radial head of the flexor digitorum 

 sublimis, the flexor pollicis longus, the pronator quadratus, and 

 lastly, the distal end of the radius. 



