918 



THE VASCULAE SYSTEM. 



surface, when the arm is abducted, by a line drawn from the middle of the clavicle 

 to the centre of the bend of the elbow. 



Relations Posterior. It lies, successively, anterior to the long head of the triceps, 

 the radial (O.T. musculo-spiral) nerve and the profunda vessels intervening ; the medial 



head of the triceps ; the insertion of the coraco- 

 brachialis ; and the brachialis. Anterior. It is 

 overlapped anteriorly by the medial border of 

 the biceps ; it is crossed, at the middle of the 

 arm, by the median nerve, and, in addition, it 

 is covered by deep and superficial fascia and 

 skin. In the cubital fossa a thickened portion 

 of the deep fascia, the-lacertus fibrosus (O.T. 

 semilimar or bicipital fascia), separates it from 

 the median basilic vein and the volar branch of 

 the medial cutaneous nerve of the forearm, both 

 of which lie in the superficial fascia. Lateral. 

 To the lateral side it is in relation, proximally, 

 with the median nerve, and, distally, with the 

 biceps. Medial. To the medial side it is in 

 relation, in the proximal part of its extent, with 

 the basilic vein, the medial cutaneous nerve of the 

 forearm, the medial cutaneous nerve of the arm, 

 and the ulnar nerve, and in the distal part with 

 the median nerve. Two vense comites, a medial 

 and a lateral, accompany the artery, and com- 

 munications between these pass across the vessel. 



Triceps 



ofunda 

 artery 



Ulnar nerve 



Superior 



ulnar 



collateral 



artery 



Median 

 nerve 



BRANCHES OF THE BRACHIAL ARTERY. 



(1) Arteria Profunda Brachii. The 

 profunda artery of the arm (O.T. superior 

 profunda) is a large branch which arises 

 from the postero- medial aspect of the 

 brachial, soon after its commencement. It 

 runs distally and laterally, with the radial 

 (O.T. musculo-spiral) nerve, in the radial 

 inferior ui Mr ul s (O.T musculo -spiral groove), and 

 divides, at the back of the humerus, into 

 two terminal branches, anterior and posterior. 

 Not infrequently the division takes place 

 at a higher level, and the artery appears 

 double. The anterior terminal branch ac- 

 companies the radial nerve through the 

 lateral intermuscular septum, and passes 

 distally, between the brachio-radialis and 

 the brachialis, to the front of the lateral 

 epicondyle, where it anastomoses with the 

 radial recurrent artery. The posterior 

 FIG. 767.-THE BRACHIAL ARTERY AND ITS terminal branch continues distally, behind 

 BRANCHES. the lateral intermuscular septum, and anas 



'tomoses, posterior to the lateral epicondyle 



with the interosseous recurrent artery and with the inferior ulnar collateral artery 

 Whilst they are posterior to the humerus one of the terminal branches give^ 

 off (a) a slender medial collateral twig, which descends in the substance of the 

 medial head of the triceps to the back of the elbow, where it anastomoses with the 

 inferior ulnar collateral artery ; (&) a nutrient branch, which enters a foramen or 

 the posterior surface of the humerus ; and (c) an ascending branch, which anasto 

 moses with the descending branch of the posterior circumflex artery. 



(2) Muscular branches are given to the biceps, coraco-brachialis, brachialis 

 triceps, and pronator teres. 



Brachio- 

 radialis 



