ioo THE SUPERIOR EXTREMITY 



carpi radialis longus lie in the distal part of the compartment 

 along the lateral side of the brachialis, to which they are 

 closely applied. The brachial artery and its venae comites 

 traverse the whole length of the compartment in relation 

 with the medial border of the biceps. The median nerve 

 also runs through the whole length of the compartment 

 lying, in the proximal half, lateral to the brachial artery, and 

 in the distal half, medial to it. The basilic vein enters the 

 compartment at the middle of the arm, where it pierces the 

 deep fascia, and then ascends along the medial side of the 

 brachial artery. 



Dissection. If the piece of wood, to which the axillary artery 

 and the nerves were previously fixed, has been detached from the 

 coracoid process, retie it to that process and proceed to clean the 

 brachial artery and its branches, its venae comites, the deep 

 proximal part of the basilic vein, and the accompanying nerves. 

 It is important that the artery should be disturbed as little as 

 possible before its relations are studied. Therefore commence 

 the dissection by cleaning the nerves and the veins, and take 

 care not to injure the branches of the artery. Begin with the 

 medial cutaneous nerve of the arm, trace it along the medial 

 side of the basilic vein and through the opening in the deep fascia 

 to its termination. As a rule it gives off no branches of dis- 

 tribution before it pierces the deep fascia, but it communicates 

 with the intercosto-brachial nerve (Fig. 16). Next follow the 

 median cutaneous nerve of the forearm along the groove between 

 the anterior border of the basilic vein and the brachial artery, and 

 through the opening in the deep fascia to the bend of the elbow. 

 It gives off several branches before it pierces the deep fascia (p. 69). 

 Now clean the basilic vein, displace it forwards and follow the 

 ulnar nerve, which descends, along the posterior angle between 

 the brachial artery and the basilic vein, to the middle of the arm. 

 Then, at the level of the insertion of the coraco-brachialis, it 

 passes backwards, accompanied by the superior ulnar collateral 

 branch of the brachial artery, pierces the medial intermuscular 

 septum, and enters the posterior compartment of the arm, where 

 it will be dissected at a later period. The median nerve should 

 next be cleaned. Follow it along the lateral margin of the 

 proximal part of the brachial artery to the middle of the arm, 

 there it crosses anterior to the artery and then descends, on its 

 medial side, to the cubital fossa ; note that the nerve gives off 

 no branches till the cubital fossa is reached. After the median 

 nerve has been cleaned, clean the vense comites of the artery. 

 Note that they anastomose across the artery frequently, and that 

 at the lower border of the subscapularis they end in the axillary 

 vein. Now displace the proximal part of the brachial artery 

 forwards and follow the radial (museum-spiral) nerve behind it, 

 to the proximal end of the sulcus for the radial nerve at the 

 back of the humerus. The radial nerve is accompanied by the 

 profunda branch of the brachial artery. Clean the branches 

 which pass from the lateral side of the artery to the biceps, 



