The Anterior Limb. 143 



along which it passes to the end of the forearm and to the ulnar side of 

 the pisiform bone. It passes to the ventral surface of the fifth digit, 

 and then turns across the hand, forming the volar arch. 



**The single brachial vein (v. brachialis) accompanies the brachial 

 artery and lies behind it. It is formed in front of the elbow by the union 

 of two vessels, the radial and ulnar veins, which accompany the corres- 

 sponding arteries, and join one another at the point of separation of the 

 latter. The radial vein anastomoses with the radial portion of the 

 cephalic at a point distal to the middle of the forearm. 



The cephalic vein (v. cephalica) is a large superficial vessel appearing 

 on the dorsal surface of the forearm. From the radial side of the latter 

 it receives a large tributary which anastomoses with the radial vein. 

 It is accompanied by branches of the superficial ramus of the radial 

 nerve. It passes to the front of the arm across the angle of the elbow, 

 lying at first on the anterior margin of the lateral head of the brachialis, 

 and afterwards on the lateral surface of the arm between the abductor 

 brachii superior and the anconaeus lateralis. It disappears from this 

 surface in the triangular space enclosed by these muscles and the inser- 

 tion of the levator scapulae major, receiving at this point a large tributary 

 from the shoulder. It appears on the medial surface of the shoulder at 

 the distal end of the axillary border of the scapula between the teres 

 major and subscapularis, entering the axillary vein at about the same 

 place as the subscapular vein, or in common with the latter. 



***The radial nerve (n. radialis) passes behind the brachial artery to 

 the posterior surface of the humerus. It perforates the anconaeus 

 medialis, appearing afterwards on the lateral side of the brachialis in 

 company with the collateral radial artery. A superficial ramus, given off 

 on the distal portion of the arm, accompanies the cephalic vein: it 

 passes along the surface of the extensor carpi radialis, dividing into 

 branches for the dorsum of the hand. The remaining portion is chiefly 

 distributed as the ramus profundus to the extensor muscles of the fore- 

 arm. 



The median nerve (n. medianus) passes distad along the medial sur- 

 face of the arm, lying at first in front of the brachial artery and then 

 on its medial side. It accompanies the brachial artery, passing beneath 

 the head of the pronator teres, and then traverses the forearm, in com- 

 pany with the radial artery, to the volar surface' of the hand. 



The ulnar nerve (n. ulnaris) lies behind the brachial artery. Toward 

 the distal extremity of the humerus it accompanies the inferior ulnar 

 collateral artery. It passes from the medial surface of the elbow, be- 

 tween the, anconaeus minimus and the base of the olecranon, to the 

 dorsal surface of the olecranon head of the flexor carpi ulnaris, and 

 then crosses the ulna obliquely, in company with the ulnar artery, to 

 the lateral border of the muscle and along it to the insertion tendon. 

 At the wrist it crosses the dorsal surface of the tendon, and passing 

 between the tendon of the sublimis and the pisiform bone, reaches the 

 volar surface of the hand. 



