597 



demarcation, the union of the V. basilica with the V. brachialis me- 

 dialis being most frequently by means of a more or less well marked 

 plexus situated two or three fingers breadth distal to the pectoralis 

 tendon. 



The V. mediana antebrachii. The V. mediana antebrachii 

 is a vein described by Spalteholz as passing "upward upon the 

 middle of the volar surface of the forearm, bifurcates in the flexure of 

 the elbow and goes partly to the V. basilica as a V. mediana basilica, 

 partly to the V. cephalica as the V. mediana cephalica". This vein 

 should, therefore, correspond to the median vein of the older termino- 

 logy, but as a matter of fact it only did so in some 18 °/o of our 

 cases, in all the remainder it coincided with the anterior ulnar vein. 

 In our observations we found the V. mediana antebrachii to be the 

 main outlet of the rete venosum volare manus, whence it passed proxim- 

 ally along the ulnar side of the volar surface of the forearm to a 

 variable termination in the vicinity of the elbow joint as follows: 



In 42 7o of cases it terminated in the V. basilica. 



In 43 7o in the V. mediana cubiti. 



In 13 7o the V. mediana antebrachii terminated by dividing into 

 the V. mediana basilica and the V. mediana cephalica, and in the re- 

 maining cases, four in number, the vein was altogether absent. 



The M-shaped arrangement of the veins in front of the elbow de- 

 scribed by British anatomists is therefore the less common of the two 

 types of venous anastomosis at the bend of the elbow between the 

 two great longitudinally directed Vv. cephalica et basilica. In the 

 more common of the two types the anastomosis is by means of the 

 V. mediana cubiti, in the less common type it is by the V. mediana 

 antebrachii dividing into the Vv. mediana basilica et mediana cephalica. 

 In three of our cases in which the less common type of anastomosis 

 was present we found, in addition, a small obliquely situated cross 

 communicating vessel between the Vv. cephalica et basilica situated 

 just proximal to the elbow joint, — apparently a rare condition. 



The V. cephalica accessoria. The V. cephalica accessoria 

 is described by Spalteholz as "a second longitudinal vessel situated 

 laterally on the forearm, which opens into the main vein". By Morris, 

 the vein is merely mentioned without description. As a matter of fact 

 the V. cephalica accessoria, though variable, is remarkably constant, as 

 we found it in no less than 82 7o of our 300 cases. 



The origin of the V. cephalica accessoria is variably from: 



a) In 39^0 some small venous radicles in the distal part of the 

 dorsal surface of the forearm. 



