206 SURGICAL APPLIED ANATOMY. [Chap. xn. 



considerable extent by the biceps muscle. Compression 

 of the brachial, unless performed carefully with the 

 fingers, can hardly avoid at the same time compression 

 of the median nerve. Thus no doubt arises the severe 

 pain that is often complained of when tourniquets, or 

 circular indiarubber bands, are applied to the limb. 

 It must also be remembered that the internal 

 cutaneous nerve lies in front of the vessel, or close to 

 its inner side, until it pierces the fascia ; that the ulnar 

 nerve lies along the inner side of the artery as far as 

 the coraco-brachialis insertion, and that behind the 

 commencement of the vessel is the musculo-spiral 

 nerve. The venae comites are placed one on either 

 side of the artery, and communicate frequently with 

 one another by short transverse branches which 

 directly cross the vessel, and which may give trouble 

 in operations upon the artery. If in ligaturing the 

 artery at its middle third the arm rests upon any 

 support the triceps may be pushed up and mistaken 

 for the biceps. If the incisions be too much to the 

 inner side the basilic vein may be cut, or the ulnar 

 nerve exposed and mistaken for the median. Tillaux 

 states that in the operation a large inferior profunda 

 artery has been taken for the brachial. Inasmuch 

 as the median nerve often derives distinct pulsation 

 from the subjacent vessel, it happens that in the 

 living subject it has been confused with the main 

 artery itself. 



The Hiusculo-spiral nerve, from its close 

 contact with the bone, which it crosses at the level 

 of the deltoid insertion, is frequently injured and 

 torn. Thus it has been damaged in severe contusions, 

 in kicks, in stabs, in bites from horses, and very 

 frequently in fractures of the humeral shaft ; or the 

 nerve may be sound at the time of fracture, and 

 become subsequently so involved in the callus formed 

 as to lead to paralysis of the parts it supplies. In a 



