978 



THE VASCULAE SYSTEM. 



Tributaries. In addition to tributaries corresponding with the branches of the 

 axillary artery, it receives the venae comites of the brachial artery, at the lower border 

 of the subscapularis ; and the cephalic vein, which joins it above the upper border of the 

 pectoralis minor muscle. 



THE SUPERFICIAL VEINS OF THE SUPERIOR EXTREMITY. 



The superficial veins of the upper limb commence in the superficial fascia of 



the palm and dorsum of the hand and of the digits. 



The Veins of the Digits and Hand. The special volar digital veins are two or 



more fine longitudinal channels which lie in the superficial fascia of the volar 



aspects of the 

 digits. They com- 

 municate, proxim- 

 ally, with a fine 

 venous network 

 which lies in the 

 superficial fascia of 



^Tributaries of cephalic vein 



Tributary of 

 cephalic vein 



Commencement, 



of basilic vein 



Dorsal 

 digital 



Dorsal venous 

 arch 



the palm, and, at 

 the proximal ends 

 of the interdigital 

 clefts, by means 

 of intercapitular 

 veins, which pass 

 dorsally between 

 the heads of the 

 metacarpal bones, 

 they open into 

 the special dorsal 

 digital veins. 



The special 

 dorsal digital veins, 

 two in each digit, 

 anastomose freely 

 together on the 

 dorsal aspects of 

 the digits. At the 

 proximal ends of 

 the interdigital 

 clefts they com- 

 municate, through 

 the intercapitular 

 veins, with the 

 special volar digi- 

 tal veins, and then 

 they unite to- 

 gether to form an 

 indefinite series of 

 dorsal metacarpal 

 veins which ter- 

 minate, a little 

 distal to the middle of the dorsurn of the hand, in a dorsal venous arch. 



The Veins of the Forearm and Arm. The veins of the forearm emerge from the 

 dorsal venous arch and from the volar venous plexus, and they vary considerably 

 in number and in size. As a rule there are two main longitudinal channels, the 

 cephalic vein on the radial side and the basilic vein on the ulnar side. In some 

 cases there is an additional median vein on the volar aspect of the forearm. 



The cephalic vein commences in the radial end of the dorsal venous arch, 

 receives the metacarpal veins of the thumb, turns round the radial margin of 



FIG. 789. SUPERFICIAL VEINS ON THE DORSUM OF THE HAND AND DIGITS. 



