The resulting traveling clot is known as an embolus (plural emboli). Like other emboli, a septic embolism may be fatal. Paradoxical embolisms represent two percent of arterial emboli. In anterograde embolism, the movement of emboli is in the direction of blood flow. Atherosclerotic plaque can rupture, resulting in a source of emboli. The majority of emboli arise because of deep vein thrombosis in the legs. Surgery is indicated in patients with pulmonary artery emboli that are surgically accessible. Arterial emboli may recur even after successful treatment. Hemodynamically significant pulmonary emboli are generally massive and typically fatal. The resulting emboli are pieces of calcified plaque. This reversal of ratios is in favor of pulmonary emboli or vasculitis. Trendelenburg was also interested in the surgical removal of pulmonary emboli. The most common sites of origin of pulmonary emboli are the "femoral" veins. Arterial emboli often occur in the legs and feet. Embolizations (dislodgement of thrombi) normally go to the lung and cause pulmonary emboli.