FRONT OF THE ARM 75 



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

 ulnar nerve inclines backwards, pierces the medial inter- 

 muscular septum and, passing behind the medial epicondyle, 

 enters the forearm. The median cutaneous nerve of the 

 forearm inclines forwards and medially, pierces the fascia 

 brachii and becomes superficial. The radial nerve is 

 behind the upper part of the artery, but it soon leaves it 

 by passing distally and laterally into the sulcus or the 

 radial nerve between the medial and the lateral heads of the 

 triceps. 



Branches of the Brachial Artery. A considerable number 

 of branches spring from the brachial artery. Those which 

 arise from its lateral aspect are irregular in number, origin, 

 and size. They are termed the lateral branches, and are 

 distributed to the muscles and integument on the front of the 

 arm. The series of medial branches which proceed from the 

 medial and posterior aspect of the parent trunk are named as 

 follows as we meet them from above downwards : 



1. A. profunda brachii. 3. A. nutricia humeri. 



2. A. collateralis ulnaris superior. | 4. A. collateralis ulnaris inferior. 



The arteria profunda brachii (O.T. superior profunda) is 

 the largest of the branches which spring from the brachial 

 trunk. It takes origin about an inch or so distal to the 

 lower margin of the teres major, and associates itself with 

 the radial (musculo-spiral) nerve, which it accompanies to 

 the back of the arm. Consequently, only a short part of the 

 vessel is seen in the present dissection. It soon disappears 

 from view between the long and medial heads of the triceps. 



The arteria collateralis ulnaris superior (O.T. inferior pro- 

 funda) is a long slender artery, which can be recognised from 

 the fact that it follows closely the course which is pursued by the 

 ulnar nerve. Its origin is somewhat uncertain. As a general 

 rule, it issues from the brachial artery opposite the insertion 

 of the coraco-brachialis, but very frequently it will be seen 

 to arise in common with the profunda brachii. It pierces 

 the medial intermuscular septum, with the ulnar nerve, and 

 descends behind the aponeurotic partition to the interval 

 between the olecranon and the medial epicondyle of the 

 humerus. 



The arteria nutricia humeri may arise directly from the 

 brachial trunk, or take origin from the superior ulnar 



