140 SURGICAL ANATOMY OF 



scapular and acromio-thoracic, and the subscapular with 

 the superior profunda, form the chief collateral channels. 



SURGICAL ANATOMY OF THE BRACHIAL REGION. 



Surface Markings. This region may be considered 

 as lying between a line drawn round the lower border 

 of the axilla, and another round the arm just above the 

 condyles of the humerus. Its general form is that of a 

 cylinder, flattened internally and externally, convex in 

 front, owing to the swell of the biceps muscle. Along 

 the inner aspect of the biceps is a well-marked groove, 

 extending from the axilla to the bend of the elbow; 

 whilst a shallow groove exists also on its outer surface, 

 becoming lost at the point of insertion of the deltoid ; 

 beneath the skin is seen in the internal groove the 

 basilic vein, and external to the biceps, the cephalic. 

 The posterior surface of the brachial region is rounded 

 at about its middle, where the greater mass of the tri- 

 ceps muscle lies, and below this point its flattened 

 sharp-edged tendon forms towards its insertion into the 

 olecranon. In the inner groove lies the brachial artery, 

 where it can be felt or seen pulsating, overlapped by the 

 inner border of the biceps at. about its middle, the mus- 

 cle forming the guide to it throughout its course, either 

 for its deligatiori or compression. The surgical consid- 

 erations . affecting this region refer chiefly to amputa- 

 tion, ligature of its vessel, fractures, and the removal of 

 tumors. 



On removing the skin, the subcutaneous cellular 

 tissue, divided into two laminae by a layer of fat, is 

 first met with, and it is in this structure that the super- 

 ficial nerves, veins, and lymphatics lie. The brachial 



