PHLEBITIS, LEG. PHLEBITIS, LEG Superficial venous thrombosis of the lower limb. The venous valves are folds of the veins walls force the blood to direct unidirectionally toward the heart, without reflux see image 1008307. Some blood can accumulate and stagnate in the cusps of the valvules, forming a thrombus like here at the level of the great saphenous vein of the leg. This thrombus may be at the origin of an obstruction thrombosis and inflammation phlebitis of the vein, as well as of an emboli