42 Anatomy Applied to Medicine and Surgery. 



The axillary vein as before mentioned lies mainly to 

 the inner side ot the artery with the arm by the side, and 

 to the inner side but chiefly in front when the arm is at 

 right angles to the body. The superior thoracic artery 

 arises from the axillary above the upper border of the pec- 

 toralis minor and then runs along that border towards the 

 thorax ; the acromio-thoracic arises close to the upper 

 border of the same muscle and the long thoracic runs 

 along its lower border. Therefore the points where the 

 upper and lower borders of the pectoralis minor cross the 

 axillary artery would represent the points of origin of 

 these branches and the lines for the borders would corre- 

 spond to the course of the superior and long thoracic 

 vessels. The course of the superior thoracic will be repre- 

 sented by a line drawn from the upper border of the third 

 rib,, starting about 3 inches from the mid-sternal line and 

 ending about half an inch behind the beak ot the coracoid 

 process and the oiigin of the acromio-thoracic will corre- 

 spond to the point where this line crosses the line of the 

 axillary artery. The landmark for the long thoracic or 

 deep external mammary will be a line drawn from the 

 lower border of the fifth rib, starting about 3^ inches from 

 the midst?rnal line and ending about half an inch below 

 the beak of the coracoid process. (Fig. 2.) 



The lines for the branches of the acromio-thoracic are : 

 lor the acromial branch^ a line drawn from the point of 

 origin of the acromio-thoracic above mentioned, to the 

 acromion process and passing over the coracoid process; for 

 the thoracic branch, the same as for the superior-thoracic, 

 and for the descending bianch, a line drawn from the point 

 of origin to the inner side of the insertion of the deltoid 

 and corresponding to the groove between the deltoid and 

 the pectoralis major. This latter line represents the course 

 of the cephalic vein also, viz : from the inner side of the 



