Bruised varicose veins on a man's legs. Varicose veins are veins that have become distended and lengthened. This happens because of defective valves in the leg veins. The valves in the leg veins usually prevent circulating blood from sinking to the feet under gravity. If the valves stop working, blood can pool downwards, leading to the characterisitic appearance of varicose veins. The superficial or saphenous veins of the legs are the most commonly affected. Treatment includes wearing elastic support, stripping (the surgical removal of the veins), or sclerotherapy, the injection of a vein with an irritant that eventually blocks it.