1 66 SURGICAL APPLIED ANATOMY. [Chap. xi. 



drawn from the third rib near its cartilage to the tip 

 of the coracoid process indicates the upper border of 

 the pectoralis minor, and the spot where this line 

 crosses the line of the axillary artery points out the 

 position of the acromio-thoracic artery. A line drawn 

 from the fifth rib near its cartilage to the tip of the 

 coracoid process indicates the lower border of the 

 pectoralis minor, and the position of the long thoracic 

 artery which runs along that border. The line of the 

 subscapular artery corresponds to the lower border of 

 the subscapularis muscle along which it runs, but 'the 

 position of this border can only be approximately 

 indicated on the living or undissected subject. 



The circumflex nerve and posterior circumflex 

 artery cross the humerus in a horizontal line that is 

 about a finger's breadth above the centre of the vertical 

 axis of the deltoid muscle. This point is of importance 

 in cases of supposed contusion of the nerve. The 

 dorsalis scapulae artery crosses the axillary border of 

 the scapula at a point corresponding to the centre of 

 the vertical axis of the deltoid muscle. These various 

 indications of the positions of the main branches of 

 the axillary artery are made while the arm hangs in 

 its natural position at the side. 



The clavicle. The skin over the clavicle is 

 loosely attached, and is easily displaced about the 

 bone. This circumstance may serve to explain why 

 the skin so often escapes actual wound in contusions 

 of the clavicular region, and in part explains the 

 infrequency of penetration of the integument in 

 fractures of the clavicle. The position of the supra- 

 clavicular nerves in front of the bone renders them 

 very liable to contusion, and accounts for the unusual 

 amount of pain that is said to sometimes follow 

 blows over the collar bone. Tillaux believes that the 

 severe pain that in rare cases persists after fracture of 

 the clavicle is due to the implication of these nerves 



