DISSECTION OF THE ANTERIOR LIMB. .11 



two of their insertion, except in the case of the latissimus dorsi, which 

 is to be left at its present length until its nerve and artery have been 

 followed. The posterior superficial pectoral should be cut away on a 

 level with the olecranon, but care is to be taken not to disturb the 

 vessels and nerves which it covers. The aponeurosis which the 

 panniculus sends within the shoulder will now be observed, and, at its 

 upper border, a small glistening band passing to be inserted into the 

 internal tuberosity of the humerus. 



The next step is to dissect out the axillary and brachial vessels, and 

 the remaining branches of the brachial plexus ; and this is an operation 

 demanding time and care. While an assistant holds the nerves on the 

 stretch, the fat and areolar connective-tissue which surround them and 

 the vessels, are to be cleaned away piecemeal, always proceeding from 

 the main trunks to the branches. In doing this, the dissector will meet 

 two groups of lymphatic glands. 



Brachial Lymphatic Glands. The upper group consists of a cluster 

 placed behind the brachial vessels, on a level with the middle of the 

 humerus. The lower group consists of one or two glands in relation to 

 the vessels, just above the elbow-joint. 



The Axillary Artery (Plates 5 and 6). This vessel has already been 

 seen passing in a curved direction from the anterior border of the 1st 

 rib, across the inner aspect of the shoulder-joint, where it rests above the 

 terminal insertion of the posterior deep pectoral, and on the tendon of 

 the subscapularis. It passes on to the teres major, and is continued as 

 the brachial artery. In this course it gives off four vessels, viz., the 

 inferior cervical, e'xternal thoracic, suprascapular, and subscapular. 

 The first two have already been dissected in the axilla. 



The Suprascapular Artery (Plate 5) is a small, tortuous vessel 

 springing from the upper surface of the axillary artery about the middle 

 of its extra-thoracic course. It passes upwards for a short distance, 

 and then divides into branches, the longest of which passes over the 

 subscapularis to reach the anterior deep pectoral. A branch passes 

 in between the subscapularis and the supraspinatus, while smaller 

 branches ai-e expended in the tendons about the shoulder. 



The Subscapular Artery (Plates 5 and 6) is a comparatively large 

 vessel, and beyond its origin the parent trunk is much reduced in calibre. 

 It arises at the interstice between the subscapularis and teres major 

 muscles ; and, disappearing between these muscles, it ascends behind 

 the glenoid border of the scapula, as far as its dorsal angle. It gives 

 off a considerable number of vessels that cannot at this stage be 

 completely followed, but near its origin it will be seen to throw off a 

 branch which runs upwards and backwards on the latissimus dorsi 

 (Plate 5). 



The Brachial Artery (Plates 5 and 6) is the direct continuation of the 



