Trendelenburg test [Friedrich Trendelenburg] , a simple test for incompetent valves in a person who has varicose veins. The person lies down and elevates the leg to empty the vein, then stands, and the vein is observed as it fills. If the valves are incompetent, the vein fills from above. If the valves are normal, they do not allow backflow of blood, and the vein fills from below.
