SURGICAL ANATOMY OF BEACHIAL ARTERY. 



405 



vessels is not the same in the right and left arms. In 61 bodies in which the 

 high division existed, it occun-ed only on one side in 43 ; on both sides, in different 

 positions, in 13 ; and on both sides, in the same position, in the remaining 5. 



Fig. 265.— Aberrant Artfrt, separating from the 



BRACHIAL AT THE MIDDLE OF THE AkM, PASSING WITH 



THE Median Nerve through the Internal Inter- 

 muscular Septum, and joining farther doavn 

 THE regular Ulnar (from R. Quain). ^ 

 a, biceps muscle ; h, triceps ; c, c, divided pronator 



teres ; d, d, d', median nerve, diverted from its usual 



course, and passing with tlie aberrant art?ry through 



the internal intermuscular septum ; e, c, c, ulnar nerve 



in its usual course ; 1, brachial artery, giving off an 



aberrant artery at the middle of the arm ; 2, the usual 



radial artery ; 3, aberrant artery, with the median 



nerve twining round it, passing at 3', through the 



internal intermuscular septum ; 3", the same farther 



down, and communicating at 4' with tlie first part of 



the normal ulnar artery, 4, given off from the brachial. 



Bramhes. — It has been already mentioned that 

 the superior prof It ruhi may give origin to the pos- 

 terior circumflex artery, and that its own origin is 

 sometimes transferred to a branch arising from the 

 axillary artery. 



The inferior profuiula is likewise occasionally 

 absent, and on that account has not been recog- 

 nised by some anatomists as a regular branch of 

 the brachial artery. 



The nn/istoiiuifif artery is sometimes much re- 

 duced in size, and in that case the inferior profunda 

 takes its place behind the humerus. 



SURGICAL ANATOMY OP THE BRACHIAL 

 ARTERY. 



The brachial artery may be easily reached for 

 the application of a ligature in any par-t of its 

 course. In the middle third of the arm its posi- 

 tion on the inside of the biceps muscle, where its 

 pulsation may be felt, is a sufficient guide for the 

 incision. From the thinness of the parts covering- 

 the artery, however, and the proximity of super- 

 ficial veins, especially the basilic, the integuments 

 and fascia must be divided with caution. A\Tien 

 the fascia has been cut through the median neive 

 generally comes into view, as it lies in front of 



the artery. Occasionally it is found necessary to divide some muscular fibres 

 before the artery is reached. 



In the lower third of the ann, the median nerve being placed to the inner 

 side, the artery is more fully exposed after division of the fascia, but here care 

 is necessary in passing the ligature round the arteiy, to avoid the venae comites 

 or their communicating cross branches, which cling very closely to the artery. 



Fi-om the very frequent occurrence of varieties in the mode of division of the 

 brachial artery into the vessels derived from it, the surgeon mrrst be prepared for 

 many deviations from the usual position of the parts, and especially for the 

 presence of two arteries in place of one in tlie lower third of the brachial region. 

 In such cases the two arteries are most frequently close together and nearly parallel, 

 and it will be easy to tie both vessels, should this be rendered necessary by the 

 nature of the injury for which the operation is performed. But, as will be seen 

 from what has previously been said of the abnormal forms of the brachial arterj-. 



