Varicose vein. Coloured scanning electron micro- graph of a sectioned varicose vein containing a damaged valve. This is one of the two saphenous veins that run up each leg under the skin, carrying blood from the foot. Varicose veins develop when the valves inside the saphenous veins fail to work properly, allowing blood to pool. The veins become conspicuously swollen and distended, and may cause pain or complications such as leg ulcers. The disorder tends to run in families and is more common in women than in men. Treatment involves wearing elastic stockings and sitting with feet up. Severe cases may require surgery to remove the vein. Magnification: x20 at 6x6cm size. x10 at 35mm size.