These are short veins which connect the superficial vein and deep veins. Deep veins run between deep muscle layers. They carry most of the blood in the legs. Superficial veins are under the skin and some are inside the muscle superficial cover (fascia). Perforator veins are commonest in the lower extremity veins. Their normal function is to carry blood from superficial to deep veins that get squeezed by the muscles pumping the blood towards the heart. This direction of flow is controlled by one way valve inside the perforator vein. These are widely present in the thighs, legs, and feet. If the valves are damaged, the blood may run in reversed direction. If neglected, they cause varicose veins and often may lead to complications below their level. These are identified through exam and ultrasound testing. It is not uncommon to have these incompetent perforator veins to be the main cause of isolated varicose veins or skin complications.