SURGICAL ANATOMY OF THE AXILLA. 135 



cated by a line passing through the axilla, drawn from 

 about the centre of the clavicle to the inner border of the 

 coraco-brachialis muscle. It lies in an envelope of ner- 

 vous cords, the median, musculo-spiral, musculo-cuta- 

 neous, ulnar, and internal cutaneous. The axillary vein 

 is very large, and lies internal to and a little in front of 

 the artery, and in ligature of the artery it is seen first, 

 and miust be drawn to one side. It is adherent to the 

 cellular tissue and by fascial attachment to the coracoid 

 process, and if wounded is liable to gape considerably, 

 and thus admit air, an accident which has happened in 

 removing axillary tumors. 



The branches of the axillary artery are usually given 

 off in the following order : the thoracica suprema, which 

 runs along the upper part of the inner wall ; the acromio- 

 thoracic, sending branches to its anterior wall ; the long 

 thoracic, lost on the thorax and mammary gland ; the 

 subscapular, which descends obliquely along the inferior 

 border of the subscapularis, and is distributed to the 

 muscles of the posterior wall, one large branch in par- 

 ticular, the dorsalis scapulce, passing to the dorsum scap- 

 ulae in the triangular interval between the two teres 

 muscles and long head of triceps ; the posterior circumflex 

 passes through the quadrilateral space formed by the two 

 teres muscles, long head of triceps, and humerus, and 

 winds round the neck of the humerus, supplies the del- 

 toid, and is accompanied by the circumflex nerve and 

 veins ; the anterior circumflex, a small branch, is supplied 

 to the articulation beneath the coraco-brachialis and bi- 

 ceps, and inosculates with the former. 



Thus, if the vessel be normal, the acromio-thoracic, 

 and thoracica suprema are given off above the pectoralis 

 minor, the external mammary about opposite its middle, 



