588 



THE ARTERIES. 



converge, the space is narrow, and bounded by the humerus, the Coraco-brachialis 

 and Biceps muscles. 



Contents. This space contains the axillary vessels and brachial plexus of 

 nerves, with their branches, some branches of the intercostal nerves, and a large 

 number of lymphatic glands, all connected together by a quantity of fat and loose 

 areolar tissue. 



Their Position. The axillary artery and vein, with the brachial plexus of 

 nerves, extend obliquely along the outer boundary of the axillary space, from its 

 apex to its base, and are placed much nearer the anterior than the posterior wall, 

 the vein lying to^the inner or thoracic side of the artery and partially concealing 

 it. At the fore part of the axillary space, in contact with the Pectoral muscles, 

 are the thoracic branches of the axillary artery, and along the anterior margin 



Anterior 

 circumflex. 



FIG. 362. The axillary artery and its branches. 



of the axilla the long thoracic artery extends to the side of the chest. At the 

 back part, in contact with the lower margin of the Subscapularis muscle, are the 

 subscapular vessels and nerves ; winding around the lower border of this muscle 

 is the dorsalis scapulae artery and veins ; and toward the outer extremity of the 

 muscle the posterior circumflex vessels and the circumflex nerve are seen curving 

 backward to the shoulder. 



Along the inner or thoracic side no vessel of any importance exists, the upper 

 part of the space being crossed merely by a few small branches from the superior 

 thoracic artery. There are some important nerves, however, in this situation 

 viz. the posterior thoracic or external respiratory nerve, descending on the sur- 

 face of the Serratus magnus, to which it is distributed ; and perforating the upper 

 and anterior part of this wall, the intercosto-humeral nerve or nerves, passing 

 across the axilla to the inner side of the arm. 



The cavity of the axilla is filled by a quantity of loose areolar tissue and a large 

 number of small arteries and veins, all of which are, however, of inconsiderable 



