52 Anatomy Applied to Medicine and Siirgery. 



extension of the forearm by the triceps is associated with 

 a very slight degree of extension of the fingers in a man- 

 ner similar to the flexion of the fingers described in con- 

 nection with the biceps muscle. The subanconeus, in re- 

 ality a few of the lower fibres of the triceps, is inserted 

 into the posterior ligament of the elbow joint and draws 

 this ligament up and out of the way during contraction of 

 the triceps. 



Landmarks of the Arm.- Arteries. The main 

 artery, the brachial, lies along the inner aspect of the 

 arm. and its course is indicated by a line drawn from the 

 junction of the anterior and middle thirds of the antero- 

 posterior fold of the axilla to midway between the con- 

 dyles of the humerus. The landmarks for the chief 

 branches of the brachial artery are, for the superior pro. 

 funda a line starting from the line of the brachial artery 

 on a level with the lower border of the latiss. dorsi or post- 

 axillary told, and passing round the arm so as to cross 

 the middle of the shaft of the humerus posteriorly and 

 emerge on the anterior surface about two inches above 

 the external condyle ; for the inferior profunda, one 

 starting from the brachial line about the middle of the 

 shaft and running downwards and inwards to the fossa 

 between the internal condyle andolecranon, while for the 

 anastomotica magna the line starts from the line of the 

 brachial about one and a half inches above the int. con- 

 dyle and passes transversely inwards around the arm. 



Veins. The basilic vein, formed by the union of the 

 ulnar and the median basilic veins, passes up the arm to 

 unite with the vena comites of the brachial artery at the 

 lower border of the subscapularis so as to form the axil- 

 lary vein. The basilic is represented by a line drawn 

 from a point one half inch inside of the biceps tendon on 

 a level about half an inch above the internal condyle to 

 the line of the brachial at the upper part of the arm. 



