ARTERIES 75 



interval, bounded above and internally by the subscapularis, 

 below by teres major, and externally by the long head of the 

 triceps. In the triangular interval it gives off ventral branches 

 to subscapular fossa, and a descending branch which runs down 

 between the two teres muscles to the angle. Supplies sub- 

 scapularis, latissimus dorsi, teres major, serratus magnus ; 

 anas, supra-scapular and posterior scapular. 



Posterior circumflex (3rd part) : arises from back of artery 

 opposite lower border of subscapularis, winds backwards 

 through quadrilateral space, bounded above by the teres 

 minor, below by the teres major, internally by the long head 

 of the triceps, and externally by the neck of the humerus. 

 Supplies deltoid, head of humerus, shoulder-joint, teres minor, 

 and long head of triceps ; anas, acromio - thoracic, anterior 

 circumflex and superior profunda. 



Anterior circumflex (3rd part) : arises from outer side of 

 artery, one branch ascends bicipital groove to shoulder-joint, 

 another winds round surgical neck of humerus ; anas, posterior 

 circumflex. 



THE BRACHIAL ARTERY. 



Extent. From lower border of teres major to half an inch 

 below bend of elbow, runs along inner borders of coraco- 

 brachialis and biceps, accompanied by venae comites. 



Relations. In front. Integument, fascia, coraco-brachialis, 

 biceps and bicipital fascia, median basilic vein. Crossed by 

 median nerve at insertion of coraco-brachialis. 



Behind. Long and inner heads of triceps, musculo-spiral 

 nerve, superior profunda vessels, coraco-brachialis, brachialis 

 anticus. 



Inner side. Internal cutaneous nerve to about middle of arm, 

 r.lnar nerve to insertion of coraco-brachialis, median nerve 

 from insertion of coraco-brachialis to elbow. 



Outer side. Coraco-brachialis and biceps. Median nerve 

 from origin of artery of insertion of coraco-brachialis. 



Branches : 



Superior profunda : arises opposite lower border of teres 

 major, winds backwards and outwards with musculo-spiral 

 nerve in the groove to triceps; gives off anterior branch 

 which pierces external intermuscular septum (anas, radial 

 recurrent) ; and ends as posterior branch behind external 

 condyle ; anas, posterior circumflex, interosseous recurrent, 

 anastomotic. Supplies triceps, anconeus. 



Nutrient : arises about middle of humerus, and enters 

 medullary foramen near insertion of coraco-brachialis. 



