272 HUMERAL ARTERY. 



on both surfaces of the scapula. This large vessel passes 

 downwards a short distance in the direction of the inferior 

 costa of the scapula, and soon sends off a branch that winds 

 round to the dorsum of the fone, to be distributed to the infra- 

 spinatus and the contiguous muscles, which is called the Dor- 

 salis Scapulae. The main trunk then inclines to the subscapu- 

 laris muscle, and generally divides into two branches, which 

 are distributed to the subsca*pularis, teres major, latissimus 

 dorsi, &c. 



Sometimes the Scapular artery divides into two branches 

 before it sends off the dorsal. In this case the last mentioned 

 artery goes off from one of those branches. 



Branches near the Os Humeri. 



The arteries which are near the body of the os humeri, at 

 its upper end, are generally two in number, and denominated 

 the Anterior and Posterior Circumflex. Sometimes they arise 

 separately, and sometimes in a common trunk from the axillary 

 artery. Frequently, one of them arises from the scapular. 



The Anterior Circumflex passes between the united heads 

 of the biceps and coraco-brachialis muscles and the body of 

 the os humeri, at a small distance below its head. It sends 

 branches to the capsular ligament, the periosteum of the os 

 humeri, the membranes of the groove for the long head of the 

 biceps, the upper portions of the biceps and coraco-brachialis, 

 and some contiguous muscles. 



The Posterior Circumflex proceeds between the subscapu- 

 laris and teres major muscles, and continues between the os 

 humeri and the head of the triceps and the deltoides. It is dis- 

 tributed to the muscles and parts about the joint, especially to 

 the deltoides. 



These arteries surround the os humeri, and the small branches 

 anastomose with each other. The Posterior Circumflex is 

 much larger than the Anterior. 



The great artery of the arm proceeds from the axilla to the 

 elbow ; and, during this course is generally denominated 



