104 THE SUPERIOR EXTREMITY 



muscular septum, and, passing behind the medial epicondyle, 

 enters the forearm. The medial cutaneous nerve of the 

 forearm inclines forwards and medially, pierces the fascia 

 brachii and becomes superficial. The radial nerve is 

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

 by passing distally and laterally into the sulcus for the 

 radial nerve, between the medial and the lateral heads of the 

 triceps. 



Branches of the Brachial Artery. Several branches arise 

 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 they arise 

 proximo-distally : 



I. A. profunda brachii. 3. A. nutricia humeri. 



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



The profunda artery (O.T. superior profunda) is the 

 largest of the branches which spring from the brachial trunk. 

 It takes origin about 25 mm. (one 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 superior ulnar collateral artery (O.T. inferior profunda) 

 is a long slender artery, which can be recognised from the 

 fact that it follows closely the course pursued by the ulnar 

 nerve. Its origin is somewhat variable. As a general rule, it 

 issues from the brachial artery opposite the insertion of the 

 coraco-brachialis, but very frequently it arises in common 

 with the profunda brachii. It pierces the medial inter- 

 muscular septum, with the ulnar nerve, and descends behind 

 that fascial partition to the interval between the olecranon 

 and the medial epicondyle of the humerus. 



The nutrient artery may arise directly from the brachial 

 trunk, or take origin from the superior ulnar collateral 

 artery. It should be sought for at the distal border of 

 the insertion of the coraco-brachialis, and the dissector 

 should not be satisfied until he has traced it into the 



