THE FRONT OF THE ARM 



103 



and the numerous connecting branches which pass between 

 them, both in front of and behind the artery, make Ihe 

 relationship still more intimate. 



Behind the brachial artery there are four muscles. 

 Proximo-distally, they are (i) the long head of the triceps, 

 which is separated from the artery by the radial nerve and the 

 profunda vessels; (2) the medial head of the triceps; (3) the 

 insertion of the coraco-brachialis ; (4) in the remainder of 

 its course the brachialis forms the posterior relation. 



N. musculo- 

 cutaneus * 



N. medianus, 



N. cut. antib. 



med. T 

 A. brachialis ' 



V. basilica J 

 N. ulnaris -'-' 



M. coraco- 

 brachialis 



I "..Sept. inter- 

 r* muse. lat. 



- Brs. of A. prof, 

 brachii 



F7-N. radialis 

 (musculo-spiral) 



' Dorsal cutaneous nerve of arm (O.T. 

 external cutan. of musculo-spiral) 



FIG. 43. Transverse section through Middle of the Arm. 



With the exception of the musculo-cutaneous nerve, all 

 the terminal branches of the brachial plexus lie in relation to 

 the brachial artery. The median nerve lies on the lateral side 

 and somewhat anteriorly in the proximal half of the arm ; it 

 crosses anterior to the artery at the level of the insertion of 

 the coraco-brachialis, and in the distal half of the arm and 

 in the cubital fossa it is to the medial side of the artery. The 

 ulnar nerve and the medial cutaneous nerve of the forearm 

 lie close to the medial side of the artery as far as the 

 insertion of the coraco-brachialis ; then they leave it. The 

 ulnar nerve inclines backwards, pierces the medial inter- 



