DISSECTION OP THE ANTERIOR LIMB. 21 



jugular. The Basilic vein pierces the posterior superficial pectoral 

 to concur in forming the brachial vein. 



2. The Anterior subcutaneous or radial vein is much smaller than the 

 preceding vessel. It begins at the front of the carpus, and, ascending 

 on the middle line of the fore-arm, it empties itself into the cephalic or 

 the median vein. 



Directions. — The thin superficial fascia in which these nerves and 

 vessels are distributed should be removed to show the deep fascia. 



Deep Fascia of the fore-arm. — This is spread in the form of a close- 

 fitting fibrous envelope around the fore-arm. Above it receives an 

 insertion from the biceps, and another from the scapulo-ulnaris ; below 

 it is continued over the carpus to form sheaths for the tendons ; while 

 by its deep face it furnishes septa to pass between the muscles of the 

 fore-arm. 



Directions. — The dissection of the back of the fore-arm is now to be 

 undertaken. The before-mentioned fascia is to be incised along the 

 lines of separation of the muscles, and these are to be cleaned and 

 isolated. The remaining portion of the posterior superficial pectoral 

 muscle, which covers the posterior radial vessels and the median nerve 

 at the inner side of the elbow, is to be removed ; and care is to be 

 taken of the ulnar vessels and nerve, which are placed beneath the 

 deep fascia, on the middle line at the back of the limb. 



The Ulnar Artery (Plates 6 and 7) is a collateral branch of the 

 brachial, from which it comes off at the lower border of the caput 

 parvum. It descends parallel to the lower border of that muscle, to 

 the space between the olecranon and the inner condyle, where it is 

 covered by the scapulo-ulnaris. It here places itself in company with 

 the ulnar nerve ; and, crossing beneath the ulnar origin of the middle 

 flexor of the metacarpus, it descends to the carpus by following the 

 tendon of the ulnar portion of the deep flexor (ulnaris accessorius), 

 being placed between the external and oblique flexors of the meta- 

 carpus. At the upper limit of the carpus it concurs in the formation 

 of the supracarpal arch, by joining a branch detached from the large 

 metacarpal artery. In this course it gives off— (1) the nutrient artery 

 to the humerus (sometimes); (2) articular branches to the elbow-joint; 

 (3) muscular branches in the neighbourhood of the joint, to the 

 scapulo ulnaris, caput parvum, and posterior superficial pectoral ; (4) 

 cutaneous branches to the skin on the inner side of the fore-arm. 



The Ulnar Vein accompanies the artery and nerve, and at the elbow 

 concurs in the formation of the brachial vein. 



The Ulnar Nerve (Plates 6 and 8) has already been partly described 

 in the dissection of the arm. At the lower part of that region it crosses 

 the ulnar artery, with which it places itself in company between the 

 olecranon and the inner condyle. It here gives off branches to the 



