THE RADIAL ARTERY 



585 



JRelations. — The artery is covered successively by the abductor poUicis longus and extensor 

 poUicis brevis, by branches of the superficial radial nerve and veins, and, just before it sinks 

 between the two heads of the interosseous muscle, by the tendon of the extensor poUicis longus. 

 The branches of the superficial radial nerve to the thumb and index finger cross it. It is at 

 first somewhat deeply placed beneath the first-mentioned extensor muscles of the thumb; 

 but subsequently it lies quite superficial, and can be felt pulsating in a little triangular depression 

 bounded on either side by the extensores pollicis longus and brevis, and above by the lower 

 end of the radius. The artery lies successively on the radial collateral ligament of the wrist, on 

 the navicular (scaphoid), the greater multangular (trapezium), the base of the first meta- 

 carpal bone, and on the dorsal ligaments uniting these bones. It has usually with it two com- 

 panion veins, and a few branches of the musculo-cutaneous nerve. 



Fig. 476. — The Radial Artery at the Wrist, Left Forearm. 

 (From a dissection in the Hunterian Museum.) 



Articular branch of the profunda 



Brachialis 



Brachio-radialis, cut 



Common extensor tendon 



Extensor carpi radialis longus and 

 brevis 



Supinator 



Dorsal interosseous artery 



Abductor pollicis longus 



Brachio-radialis, cut 



Extensor pollicis brevis 



Dorsal carpal ligament 

 Extensor carpi radialis longus 



Radial artery 



First dorsal metacarpal artery 



Extensor pollicis longus 



First dorsal interosseous muscle 



First dorsal metacarpal artery 



Princeps pollicis artery 



Dorsal digital artery — 



Triceps 



Rete over olecranon 



Interosseous recurrent artery 

 Anconeus, cut 



Extensor carpi ulnaris 

 Flexor carpi ulnaris 



Origin of extensor pollicis longus and 

 indicis proprius 



Dorsal branch of volar interosseous 



artery 

 Interosseous membrane 



Dorsal ulnar carpal artery 

 Extensor carpi radialis brevis 

 Dorsal radial carpal artery 



Fourth dorsal metacarpal artery 

 Third dorsal metacarpal artery 

 Second dorsal metacarpal artery 



(1) The dorsal radial 



The branches of the radial artery at the wrist are:- 

 carpal; (2) the first dorsal metacarpal. 



(1) The dorsal radial carpal branch [ramus carpeus dorsalis] arises from the radial as the 

 latter vessel passes under the abductor pollicis longus, and runs medially beneath the ex- 

 tensor carpi radialis longus and brevis, and the extensor polhcis longus, across the dorsal surface 

 of the carpus, to anastomose with the dorsal ulnar carpal and with the terminal twigs of the 

 posterior branch of the volar interosseous artery. This anastomosis is called the dorsal carpal 



