FRONT OF THE ARM 77 



carried distally in front of the medial epicondyle of the 

 humerus, in the interval between the brachialis and the 

 pronator teres. It anastomoses in this situation with the 

 anterior ulnar recurrent artery. The posterior branch pierces 

 the medial intermuscular septum and will be seen later 

 on in the posterior compartment of the arm. 



The N. Cutaneus Brachii Medialis and Nervus Cutaneus 

 Antibrachii Medialis (O.T. Lesser Internal Cutaneous and 

 Internal Cutaneous Nerves). Very little more requires to 

 be said about these nerves. Their origin within the axilla has 

 already been noted, and they have been traced to their distri- 

 bution from the points where they pierce the investing 

 fascia brachii. It only remains for the dissector to examine 

 them in that part of their course in which they lie under 

 cover of the fascia brachii. It will be observed that they both 

 lie along the medial side of the brachial artery. The medial 

 cutaneous nerve of the arm gives off, as a rule, no branches 

 in this situation, except one or more twigs of communica- 

 tion to the intercosto-brachial nerve. The medial cutaneous 

 nerve of the forearm gives off the branch which pierces 

 the fascia to supply the skin in front of the biceps brachii. 



Nervus Medianus et Nervus Ulnaris (Median and Ulnar 

 Nerves). These large nerve trunks do not furnish any 

 branches in the arm. The median nerve arises in the axilla 

 by two heads from the lateral and medial cords of the 

 brachial plexus. It proceeds distally upon the lateral 

 and superficial aspect of the axillary and brachial arteries, 

 until it approaches the level of the insertion of the coraco- 

 brachialis. Here it lies in front of the brachial artery. 

 Finally, it reaches the medial side of the vessel, and main- 

 tains this position for the rest of its course in the arm. 



The ulnar nerve is the largest branch of the medial cord 

 of the brachial plexus. It descends upon the medial side of 

 the axillary and brachial arteries, and at the insertion of the 

 coraco-brachialis it encounters the superior ulnar collateral 

 artery. Accompanied by this vessel, it leaves the brachial 

 artery, passes backwards through the medial intermuscular 

 septum, and it is continued downwards, upon the posterior 

 aspect of this aponeurotic partition, to the interval between 

 the olecranon and medial epicondyle of the humerus. 



Dissection. The muscles should now be thoroughly cleaned, and the 

 musculo-cutaneous nerve and its branches dissected out. 



