Chap, xi.] THE DELTOID. 187 



from the latissimus dorsi to join the pectoralis major, 

 coraco-brachialis, or biceps muscles. This slip may 

 give rise to confusion during the operation, and may 

 be mistaken for the coraco-brachialis. 



The axillary nerves. Any of the axillary 

 nerves may be injured by a wound, the median 

 being the most frequently damaged, and the musculo- 

 spiral the least frequently. The comparative im- 

 munity of the latter is explained by its deep 

 position, its situation at the inner and posterior 

 aspect of the limb, and its large size. The nerves are 

 very seldom torn by a traction on the limb short of 

 more or less complete avulsion. Indeed, if forcibly 

 stretched, they are disposed rather to become torn 

 away from their attachments to the spinal cord than to 

 give way in the axilla. Thus, Flaubert records a case 

 where the last four cervical nerves were torn away 

 from the cord during a violent attempt to reduce a 

 dislocated shoulder. 



The deltoid region. This region, comprising 

 as it does the " point " of the shoulder, is limited 

 in all parts by the deltoid muscle. The deltoid 

 covers the upper end of the humerus and the 

 shoulder joint. Between the joint and the surface, 

 therefore, are only the skin and superficial fascia, the 

 deltoid in its sheath, and some loose connective tissue 

 (the subdeltoid tissue) in which is found the great 

 subacromial bursa. This subdeltoid tissue sometimes 

 assumes the form of a distinct thick membrane, and 

 may have an important influence upon the locali- 

 sation of purulent collections proceeding from the 

 joint. The fatty tissue over the deltoid is a favourite 

 seat for lipomata, and it is in this situation that the 

 tendency of these growths to change their position 

 is sometimes seen. Thus, Erichsen records a case 

 where the tumour slid downwards from the shoulder 

 to the breast. 



