Chap xi.) THE AXILLA. 209 



the back that converge to the axilla are derived from 

 the neck over the trapezius muscle, and from the 

 whole dorsal and lumbar regions as far down as the 

 iliac crest. 



The removal of axillary glands is an operation 

 frequently undertaken. It will be understood from 

 their position that these bodies, when diseased, are 

 very apt to become adherent to the axillary vessels, 

 and especially to the vein. The latter vessel has 

 frequently been wounded during the removal of 

 gland tumours, and in one case at least the artery 

 was accidentally cut (Holmes). 



The axillary vessels. The axillary vein is 

 formed by the union of the basilic with the two venae 

 comites of the brachial artery. This union commonly 

 takes place at the lower border of the subscapular 

 muscle, and the vein is therefore shorter than the 

 artery. Sometimes the vein does not exist as a single 

 trunk until just below the clavicle. This condition, 

 when it exists, is very unfavourable to operations 

 upon the artery, as many transverse branches cross 

 that vessel to unite the veins that lie on either side of 

 it. The axillary vein, being comparatively near the 

 heart, is readily influenced as regards its contained 

 blood by the inspiratory movement. Thus it happens 

 that in many instances of wound of the vessel, or of 

 its larger tributaries, air has been drawn into the 

 venous canal and death has ensued. The entrance 

 of air into the main vein is perhaps aided by 

 the circumstance that the costo-coracoid membrane 

 (upper part of clavi-pectoral fascia) is adherent 

 to the vessel, and thus tends to maintain it in a 

 patent condition when wounded. This connection 

 with the fascia is supposed by some to in part ac- 

 count for the furious bleeding that occurs from this 

 vein when it is divided. 



The vein is more often wounded than is the artery, it 

 04 



