598 



b) In 28 7o fr^ni the ulnar extremity of the arcus venosus dorsalis. 



c) In 167o froQi the V. cephalica itself at the spot where that 

 vein turns round the radial border of the forearm (see Fig. 3). In 

 these cases the V. cephalica accessoria was of large size and terminated 

 in the V. cephalica at a more proximal level, so that it was nothing 

 more than a species of short circuiting vein between the distal and 



proximal parts of the main longi- 

 tudinal venous stem, 



d) In the remaining percentage 

 of cases the vein was practically in- 

 appreciable. 



The V. mediana cubit i. The 

 V. mediana cubiti is described as "a 

 connecting branch, which usually 

 leads obliquely upward in the flexure 

 of the elbow from the V. cephalica 

 to the V. basilica and, lateralward 

 from the lacertus fibrosus, anastomoses 

 with the deep veins". We found the 

 vein to be remarkably constant inas- 

 much as it was present in 84 %, and 

 in 43 ^/o it received as a tributary 

 the V. mediana antebrachii. In 4% 

 the vein arose from the V, cephalica 

 much more distally than usual, that 

 is, at about the middle of the forearm, 

 is to transfer the main venous return from 



V. cephalica 

 V. basilica 



V. mediana cubiti 



V. cephalica ac- 

 cessoria 



V. mediana ante- 

 brachii 



Fig. 3. Origin of the V. cephalica 

 accessoria in the V. cephalica. 



The function of the vein 



the radial to the ulnar side of the forearm. 



In addition to the foregoing main venous trunks we also found 

 small irregular plexuses on both the dorsal and volar surfaces of the 

 forearm which opened into the four longitudinal veins already de- 

 scribed. The plexuses did not however ever assume the extraordinary 

 prominence attributed to them in the illustrations of such modern text- 

 books as Morris and Spalteholz. 



Abnormalities. Amongst the abnormal veins noted by us were 

 an apparent reduplication of the V. mediana cubiti (see Fig. 4), the 

 extra vessel lying on the proximal side of the main trunk, found in 

 47o- Id two cases there was a somewhat similar venous connection 

 between the V. cephalica and the V. cephalica accessoria. In four 

 cases the V. cephalica did not give off the V. mediana cubiti, the latter 

 vein being apparently represented by the terminal portion of the V. 



