The skin overlying the region where a venous "cut-down" is made to access the Great saphenous vein in supplied by

Cut open procedure/ venesection is done on the great saphenous vein as it lies in front of medial malleolus.Saphenous nerve is identified and not injured as it lies in front of great saphenous vein.Saphenous nerve, branch of posterior division of femoral nerve, pierces the deep fascia on the medial side of the knee between saorius and gracilis, runs downwards in front of the great saphenous vein.It supplies skin if the medial side if the leg and the medial border of foot up to the ball of great toe.This vein is used for transfusion of blood/fluids in case of non-availability pr collapse of other veins.{Reference: BDC 6E pg no. 127}