CONTENTS OF AXILLA. 17 



thicker and more prominent than the anterior, especially near 

 the arm. 



On the inner wall of the axilla lie the first five ribs, with their inner wall ; 

 intervening intercostal muscles, and the part of the serratus magnus 

 (c) taking origin from those bones. On the outer side the space outer wall ; 

 has but small dimensions, and is limited by the humerus and the 

 coraco-brachialis and biceps muscles (G and H). 



The apex of the hollow is situate between the clavicle, the upper apex ; 

 margin of the scapula, and the first rib ; and the forefinger may be 

 introduced into the space for the purpose of ascertaining the upper 

 boundaries, and the depth. The base of the pyramidal fossa is base, 

 turned downwards, and is closed by the thick aponeurosis reaching 

 from the anterior to the posterior fold. 



Contents of the space. In the axilla are contained the axillary contents of 

 vessels and the brachial plexus of nerves with their branches ; the space- 

 some branches of the intercostal nerves ; together with lymphatic 

 glands, and a large quantity of loose areolar tissue and fat. 



Position of the trunks of vessels and nerves (fig. 4). The large Position of 

 axillary artery (a) and vein (6) cross the outer portion of the 

 space in passing from the neck to the upper limb. The part 

 of each vessel now seen lies close to the humerus, reaching 

 beyond the line of the anterior fold of the armpit, and is 

 covered only by the common superficial coverings, viz., the skin, 

 the fatty layer or superficial fascia, and the deep fascia. Behind 

 the vessels are the subscapularis (F) and the tendons of the latis- 

 simus and teres muscles (D and E). To their outer side is the 

 coraco-brachialis muscle (G). 



On looking into the space from below, the axillary vein (6) lies vein ; 

 on the thoracic side of the artery. 



After the vein has been drawn aside, the artery will be seen to nerves, 

 lie amongst the large nerves of the upper limb, having the median 

 trunk (!) to the front and outer side, and the ulnar ( 3 ) and the 

 small nerve of Wrisberg ( 5 ) to the inner side, the internal cutane- 

 ous ( 2 ) to the inner side and somewhat in front, and the musculo- 

 spiral ( 4 ) and circumflex nerves beneath it. This part of the artery 

 gives 1 'ranches to the side of the chest and the shoulder. The vein 

 receives some branches in this spot. 



Position of the branches of vessels and nerves. The several branches situation of 

 of the vessels and nerves have the undermentioned position with Draucnes: 

 respect to the boundaries of the axilla. 



Close to the anterior fold, and concealed by it, the long thoracic in front ; 

 artery runs to the side of the chest. Taking the same direction, 

 though nearer the middle of the hollow, a small external mammary 

 artery and vein are occasionally present. 



Passing down the posterior wall, within the free margin of the behind; 

 fold in contact with the lower edge of the subscapularis muscle, 

 are the subscapular vessels and nerves (d) ; and near the outer, 

 humeral, end of the subscapularis the posterior circumflex vessels (e) 

 and the circumflex nerve bend backwards beneath the large 

 trunks. 



D.A. C 



