SURGICAL ANATOMY OF UPPER EXTREMITY. 121 



CHAPTEK IV. 



SUEGICAL ANATOMY OF THE UPPER EXTREMITY. 

 Region of the Shoulder. 



Surface Markings. The convexity of the shoulder is 

 due to the deltoid muscle, and the globular head of the 

 humerus. The bony processes, the coracoid, acromion, 

 spine of scapula, globular head of humerus, and the en- 

 tire extent of the clavicle, can be readily felt, and their 

 exact relation with regard to each other should be noticed 

 and compared, their respective bearings with the other 

 bony prominences of the upper extremity carefully studied 

 both at rest and in action. The precise relations of these 

 surface marks is of the utmost importance in the diag- 

 nosis of fracture, dislocation, or other injury to the 

 shoulder-joint, and moreover they serve as guides for the 

 direction of the knife in amputations or excisions. When 

 the arm hangs along the side with the palm turned for- 

 wards, the acromion, epicondyle, and styloid process of 

 radius externally, and internally, the head of humerus, 

 epitrochlea, and styloid process of ulna, correspond ex- 

 actly, and their mutual relations are to be noted in every 

 position of the joint. 



Anterior and Lateral Aspects' of the Shoulder : Surface 

 Markings. Anteriorly, immediately below the clavicle, 

 is a fossa in which the pulsations of the first part of the 



