In order for blood to return to the heart from the legs, it must travel upwards, against gravity. Contraction of leg muscles moves the blood upwards, and one-way valves in our veins prevent the blood from leaking backwards. Varicose veins, or greater saphenous vein varices, are large superficial veins in the legs. It appears that dilation (enlargement) of the vessels occurs first, leading to leaky valves. Varicose veins are a precursor to thrombophlebitis (clot formation and inflammation in the veins) and ulcer formation (painful skin erosions subject to infection). Thrombophlebitis, initially viewed as a painful but non-life-threatening condition, has shown some association with blood clot formation in the deep veins of the leg (deep vein thrombosis or DVT) as well as release and floating of the clot to the lung (pulmonary embolism or PE). Clearly, these are potentially dangerous outcomes that should be avoided, and thus it makes sense to have varicose veins evaluated by an expert, such as a vascular medicine physician or a vascular surgeon.