642 THE VASCULAR SYSTEMS 



opposite that vessel from the outer side of the axillary artery. It passes horizon- 

 tally outward beneath the Coracobrachialis and short head of the Biceps lying 

 upon the fore part of the neck of the humerus, and, on reaching the bicipital 

 groove, gives off an ascending branch which passes upward along the groove 

 to supply the head of the bone and the shoulder-joint. The trunk of the vessel 

 is then continued outward beneath the Deltoid, which it supplies, and anasto- 

 moses with the posterior circumflex artery. 



The Brachial Artery (A. Brachialis) (Fig. 461). 



The brachial artery (a. brachialis) commences at the lower margin of the tendon 

 of the Teres major, and, passing down the inner and anterior aspect of the arm, 

 terminates about half an inch below the bend of the elbow, where it divides into 

 the radial and ulnar arteries. At first the brachial artery lies internal to the humerus, 

 but as it passes down the arm it gradually gets in front of the bone, and at the bend 

 of the elbow it lies midway between the two condyles. 



Relations. This artery is superficial throughout its entire extent, being covered, in front, 

 by the integument, the superficial and deep fasciae; the bicipital fascia separates it opposite the 

 elbow from the median basilic vein; the median nerve crosses it at its middle; behind, it is 

 separated from the long head of the Triceps by the musculospiral nerve and superior profunda 

 artery. It then lies upon the inner head of the Triceps, next upon the insertion of the Coraco- 

 brachialis, and lastly on the Brachialis anticus. By its outer side, it is in relation with the 

 commencement of the median nerve and the Coracobrachialis and Biceps muscles, the two 

 muscles overlapping the artery to a considerable extent. By its inner side, its upper half is in 

 relation with the internal cutaneous and ulnar nerves, its lower half with the median nerve. 

 The basilic vein lies on the inner side of the artery, but is separated from it in the lower part 

 of the arm by the deep fascia. The brachial artery is accompanied by two venae comites, 

 which lie in close contact with the artery, being connected at intervals by short transverse 

 communicating branches. 



PLAN OF THE RELATIONS OF THE BRACHIAL ARTERY. 



In front. 



Integument and fascia?. 



Bicipital fascia, median basilic vein. 



Median nerve. 



Overlapped by Coracobrachialis and Biceps. 



Outer side. f >. Inner side. 



Median nerve (above). ( ^ hial ) Internal cutaneous and ulnar nerves. 



Coracobrachialis. \ / Median nerve (below). 



Biceps. J Basilic vein 



Behind. 



Triceps (long and inner heads). 

 Musculospiral nerve. 

 Superior profunda artery. 

 Coracobrachialis. 

 Brachialis anticus. 



