158 HANDBOOK OF ANATOMY 



radius, it terminates by dividing into the radial and ulnar 

 arteries. 



The brachial artery passes downwards and outwards, and lies 

 on, successively, long head of triceps, insertion of coraco- 

 brachialis, brachialis anticus, and is covered by the inner border 

 of biceps. 



In its upper half the median and ulnar nerves lie re- 

 spectively on the external and internal sides of the artery, and at 

 the middle the median nerve crosses over to the inner side of 

 the artery, while the ulnar nerve passes to the back of the arm, 



Branches. 1. Superior Profunda, runs downwards and back- 

 wards with the musculo-spiral nerve to the back of the arm. 



2. Inferior Profunda, runs downwards and backwards with the 

 ulnar nerve to the back of the elbow-joint. 



3. Anastomotic pierces the internal intermuscular septum and 

 passes also to the back of the elbow-joint. 



4. Small muscular branches are given off to the adjacent 

 muscles. 



Radial Artepy. The radial artery is the smaller of the two 

 terminal branches of the brachial artery, but the more direct 

 continuation of the parent trunk. It passes down the outer 

 side of the forearm, and at the wrist winds round the trapezium 

 to reach the back of the hand ; it then comes back through the 

 first interosseous space, and anastomoses with the deep branch 

 of the ulnar artery to form the deep palmar arch. 



It lies successively on insertion of biceps, supinator brevis, 

 pronator radii teres, radial head of flexor sublimis digitorum, 

 flexor longus pollicis, pronator quadratics, anterior ligament of 

 wrist- joint. 



It is covered by inner border of supinator longus (brachio- 

 radialis) in its upper two-thirds. The lower third is sub- 

 cutaneous. 



The radial nerve is in relation to the artery in its middle 

 third, and lies on its outer side. 



Branches. 1. Superficial Volar, which arises just above the 

 wrist, and, passing down over the ball of the thumb, anasto- 

 moses with the superficial branch of the ulnar artery to form 

 the superficial palmar arch. 



