

THE EADIAL AETEEY. 919 



(3) Nutrient. A small artery which arises from the middle of the brachial and 

 enters the nutrient foramen 011 the antero-medial surface of the body of the 

 humerus. 



(4) Arteria Collaterals Ulnaris Superior. The superior ulnar collateral artery 

 (O.T. inferior profunda) is smaller than the profunda, with which it sometimes arises 

 by a common trunk ; usually, however, it springs from the postero-medial aspect of 

 the middle of the brachial artery. It runs distally and posteriorly, with the ulnar 

 nerve, through the medial intermuscular septum, and then, passing more vertically, 

 reaches the back of the medial epicondyle of the humerus, where it terminates by 

 anastomosing with the dorsal and volar ulnar recurrent and inferior ulnar 

 collateral arteries. 



(5) Arteria Collateralis Ulnaris Inferior. The inferior ulnar collateral artery 

 (O.T. anastomotic) arises from the medial side of the brachial artery about 50 mm. (2 

 inches) above its termination. It runs medially, posterior to the median nerve and 

 anterior to the brachialis. Then it pierces the medial intermuscular septum, and 

 turns laterally, between the medial head of the triceps and the posterior surface of the 

 bone, to the lateral epicondyle. It supplies the adjacent muscles and anastomoses, 

 anterior to the medial epicondyle, with the volar ulnar recurrent, behind the medial 

 epicondyle with the dorsal ulnar recurrent and the superior ulnar collateral, at 

 the middle of the back of the humerus with the medial collateral branch of the 

 profunda, and posterior to the lateral epicondyle with the posterior terminal branch 

 of the profunda and with the interosseous recurrent artery. 



ARTEEIA RADIALIS. 



The radial artery (Figs. 768, 769, and 770) is the smaller of the two terminal 

 branches of the brachial artery, but it is the more direct continuation of the parent 

 trunk. It commences, in the cubital fossa, opposite the neck of the radius, and 

 terminates in the palm of the hand, by anastomosing with the deep branch of the 

 ulnar artery, and thus completing the deep volar arch (O.T. palmar). 



The trunk is divisible into three parts. 



The first part lies in the volar part of the forearm. It runs distally and some- 

 what laterally to the apex of the styloid process of the radius. The second part 

 curves round the lateral side of the wrist, and across the back of the os mult- 

 angulum majus, to reach the proximal end of the first interosseous space. The 

 third part passes volarwards, through the first interosseous space, to the palm of the 

 hand, where it joins the deep branch of the ulnar artery. 



Relations of the First Part Dorsal. It passes successively across the volar 

 aspects of the following structures : the tendon of insertion of the biceps, the supinator, 

 the pronator teres, the radial portion of the flexor digitorum sublimis, the flexor pollicis 

 longus, the pronator quadratus, and the volar ligament of the wrist- joint. 



Volar. The artery is covered superficially, in the proximal half, by the volar border of 

 the brachio-radialis ; in the remainder of its extent it is covered only by skin and fasciae. 



To the radial side are the brachio-radialis, and the superficial branch of the radial 

 nerve (O.T. radial nerve). The nerve lies quite near to the middle third of the artery. 

 To the ulnar side are the pronator teres, proximally, and the flexor carpi radialis, distally. 

 Two venae comites, one on each side, accompany the artery. 



Branches of the First Part. (1) The radial recurrent arises in 'the cubital fossa 

 where it springs from the lateral side of the radial, on the volar surface of the supinator. It 

 runs towards the radial border of the forearm, passes between the superficial and deep divi- 

 sions of the radial (musculo-spiral) nerve, and then runs proximally to the lateral epicondyle 

 >f the humerus, where it anastomoses with the anterior terminal branch of the profunda. 

 The radial recurrent supplies numerous muscular branches to the brachio-radialis, the 

 supinator, the extensor carpi radialis longus, and the extensor carpi radialis brevis. 



(2) Muscular branches to the muscles on the radial side of the volar aspect of the 

 forearm. 



(3) The superficial volar branch (Fig. 768) is a slender vessel which arises a short 

 distance proximal to the wrist and runs distally, across the ball of the thumb. It usually 

 pierces the superficial muscles of the thenar eminence, and terminates either in their 

 substance or by uniting with the ulnar artery and completing the superficial arch of 

 the palm of the hand. 



