DISSECTION OF SUPERFICIAL STRUCTURES 63 



some muscle fibres will be brought into view ; they connect the 

 skin on the ulnar margin of the palm with the deep fascia, 

 and constitute the palmaris brevis muscle. 



When the skin is completely removed it must not be thrown 

 away but must be kept to be wrapped round the part where the 

 dissection is not proceeding. 



Cutaneous Veins of the Superior Extremity. After the skin 

 has been removed proceed to display the cutaneous veins, because 

 they are, except here and there, the most superficial structures, 

 but be careful to preserve any nerves met with as the veins are 

 being cleaned (Figs. 31, 32). 



Commence at the interval between the pectoralis major and 

 the deltoid and follow the cephalic vein distally, being careful to 

 preserve the tributaries which join it. At the bend of the elbow 

 secure a large communicating branch called the median cubital 

 vein ; it runs obliquely, proximally, and medially, and joins the 

 basilic vein, about 30 mm. proximal to the level of the medial 

 epicondyle. The median cubital vein is joined at its distal 

 border by a vein which pierces the deep fascia and connects the 

 median cubital vein with the deep veins of the forearm. After 

 the median cubital vein and its connections have been displayed, 

 follow the cephalic vein distally, along the forearm and round its 

 radial margin, to the dorsum of the hand where it commences, 

 dorsal to the first metacarpal bone, in the radial extremity of the 

 dorsal venous arch. The dorsal venous arch crosses the dorsum 

 of the hand, from the radial to the ulnar side, and at its ulnar 

 end, which lies opposite the interspace between the fourth and 

 fifth metacarpal bones, the basilic vein commences. Follow 

 the basilic vein proximally. It passes at first along the dorsal 

 aspect of the ulnar border of the forearm, then turns round the 

 ulnar border to the front, and ascends to the arm, where it is 

 joined by the median cubital vein already dissected. Follow the 

 basilic vein proximally beyond its junction with the median 

 cubital vein to the middle of the arm where it pierces the 

 deep fascia, at the level of the insertion of the coraco-brachialis 

 muscle. As you clean it, in the lower part of the arm, look for 

 some superficial cubital lymph glands which lie in the superficial 

 fascia ; a little proximal to the elbow they receive lymph from the 

 fingers, palm, and the anterior aspect of the forearm, and are apt 

 to become inflamed and painful when wounds of those parts 

 become septic. The cephalic and the basilic veins receive tribu- 

 taries, which vary in number and size, both from the dorsal and 

 the volar surfaces of the forearm and hand. 



When the cephalic and basilic veins and their main tributaries 

 have been cleaned, return to the dorsum of the hand, clean the 

 dorsal venous arch and the tributaries which pass to it from the 

 digits ; they are (i) three dorsal metacarpal veins, one opposite 

 each of the three medial interdigital clefts ; (2) thefradial dorsal 

 digital vein from the index finger. On the dorsum of each digit 

 look for two dorsal digital veins, one along the radial and one 

 along the ulnar border. The dorsal digital veins of the thumb 

 join the cephalic vein ; the ulnar dorsal digital vein of the little 

 finger usually joins the basilic vein ; the other dorsal digital 

 veins terminate in the dorsal metacarpal veins. The two dorsal 

 digital veins on each finger are united by many channels which 

 form a series of arcades, the dorsal digital venous arches. The 



