338 A MANUAL OF ANATOMY 



Superiorly the muscle sends a pointed projection upwards on 

 either side of the lower part of the insertion of the deltoid. 



Insertion. — ^The inner part of the rough triangular surface on and 

 below the coronoid process of the ulna. 



Nerve-supply. — (i) The musculo-cutaneous nerve, and (2) a twig 

 from the musculo-spiral nerve. 



Action. — ^The muscle is a direct flexor of the elbow- joint. 



Brachial Artery. — ^The brachial artery is the continuation of the 

 axillary, and it extends from the lower border of the teres major to 

 a point just below the bend of the elbow, where it divides opposite 

 the upper part of the neck of the radius into the radial and ulnar 

 arteries. It is at first internal to the humerus, but gradually 

 inclines to the front of the bone, and at the elbow it is equally 

 distant from the two epicondyles. The course of the vessel is 

 indicated by a line drawn from a point midway between the anterior 

 and posterior folds of the axilla at the humerus to a point midway 

 between the epicondyles of the bone. The artery is accompanied 

 by two vense comites, one on either side, which communicate with 

 each other over the vessel at frequent intervals. It is for the most 

 part superficial, being only slightly overlapped . by the coraco- 

 brachialis and biceps. At the bend of the elbow, however, it sinks 

 deeply under cover of the semilunar fascia, and lies in the anti- 

 cubital space. 



Relations — Superficial. — Skin, superficial and deep fasciae, median 

 nerve about the centre of the arm, semilunar fascia of the biceps, and, 

 superficial to this, the median basilic vein. Deep. — ^The long head 

 of the triceps, with the intervention of the musculo-spiral nerve and 

 superior profunda artery, inner head of the triceps, insertion of the 

 coraco-brachialis, and brachialis anticus. External. — The coraco- 

 brachialis and biceps, both of which slightly overlap the vessel, 

 external vena comes, and the median nerve in the upper half of the 

 arm. Internal. — ^The internal vena comes, internal cutaneous nerve 

 (which may be slightly over the vessel) as low as the centre of the 

 arm, ulnar nerve also as low as the centre, median nerve in the lower 

 third, and basilic vein, which is superficial to the deep fascia in the 

 lower half, but beneath it in the upper half. The nerve most 

 intimately related to the artery is the median, which lies on its 

 outer side in the upper half of the arm, in front of it for a little at the 

 centre, and on its inner side in the lower third. 



Branches. — ^The vessel gives off from its outer side a series of 

 branches which are distributed to the muscles and integument 

 of the front of the arm. The named branches arise from the 

 inner and back part of the trunk. They are called superior 

 profunda, inferior profunda, nutrient, and anastomotica magna. 



The superior profunda artery is a large vessel which arises 

 from the back of the brachial near its commencement. It passes ' 

 downwards and backwards with the musculo-spiral nerve between < 

 the long and inner heads of the triceps, and it then winds round the 

 back of the humerus, lying with the nerve in the spiral groo^•^ 



