Varicose veins with foot complications. Varicose veins arise in the legs due to incompetent valves in the tributary veins connecting the deep and superficial veins, and later the valves of the superficial veins themselves. The term varicose implies that the veins have become distended due to becoming engorged with blood. Blood is aided in its return to the heart from the legs via a musculovenous pump. Contraction of the muscles of the leg during movement compresses the surrounding veins, moving the blood towards a region of lower intravascular pressure i.e. the heart. Accordingly, the deeper veins undergo more compression and thus have a higher pressure within them. The veins also possess valves, which only open in one direction and prevent retrograde blood flow to the legs. The perforating veins of the leg that connect the deep and superficial veins also contain valves to help maintain unidirectional flow from the superficial to the deep veins. When these valves fail, the blood from the higher-pressured deep veins can flow back into the superficial veins, causing them to engorge. As a result of their engorgement, their valves can no longer close; resulting in venous pooling in the superficial veins as they no longer oppose retrograde blood flow due to gravity. The venous pooling produces a greater intraluminal pressure within the veins, which distorts them further and gives them their torturous appearance.