VENOUS INSUFFICIENCY. VENOUS INSUFFICIENCY Venous reflux. The veins insure the return of the desoxygenated blood toward the heart. Numerous veins, particularly those of the limbs, possess venous valves, fold of the vein wall toward the heart. These valvules force the blood of the veins to circulate toward the heart, with no possibility to return backwards drawing on the top. If a venous valvule fails, like here at the level of the great saphenous vein of the leg drawing on the bottom, the blood