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PART III 

 THE UPPER EXTREMITY 



Surface markings. The clavicle (p. 225) is convex forwards in its 

 inner two-thirds and concave forwards in the outer third. Just where 

 it articulates with the acromion process it has a considerable upward 

 projection. The acromion process and the spine of the scapula are 

 easily traced towards the vertebral column, the base of the spine 

 corresponding to the third rib. 



The meeting of clavicle and acromion constitute the shoulder. The 

 roundness of the shoulder is due to the presence of the large head of 

 the humerus and its tuberosities ; over this the deltoid is thinly spread. 

 After amputation at, or excision of, the shoulder-joint, the prominent 

 ' shoulder ' remains, but the ' roundness of the shoulder' has vanished. 



The lesser tuberosity is the inner ; between it and the outer, the 

 bicipital groove may be felt : it is exactly at the front of the head of 

 the bone when the arm is by the side and slightly rotated outwards. 



The coracoid process is found on thrusting the fingers into the 

 space between the pectoralis major and deltoid, at about an inch below 

 the junction of the cylindrical and flattened parts of the clavicle. To 

 make sure that the fingers have not gone too far outwards and are 

 pressing against the lesser tuberosity of the humerus, the arm should 

 be rotated. 



The course of the axillary artery may be indicated by a line from 

 the middle of the clavicle to the groove along the inner side of the 

 coraco-brachialis and biceps, the arm being abducted and rotated 

 outwards. 



The prominent mass of the biceps in front of the arm suddenly tapers 

 into the strong tendon, from the inner side of which the bicipital fascia 

 may perhaps be made out as it expands over the muscles which are 

 arising from the inner condyle of the humerus. 



Along the inner side of the biceps is the groove which is continued 

 down from between the axillary folds ; in it runs the brachial artery. 

 The inner border of this muscle is the guide in tying that vessel. 

 The muscle overhangs the artery. 



