Vascular sink is a manifestation of significant weakness in the lower extremities after prolonged standing or heavy physical work. The main causes of vascular sink are divided into venous thrombosis of the lower extremities, and venous insufficiency of the lower extremities. 1, when venous thrombosis is formed in the lower extremities, the formed thrombus will occupy the pathway of blood return and affect the venous return, resulting in the deposition of blood in the lower extremities in the lower legs, especially after prolonged standing or heavy physical labor, the symptoms of obvious weakness in the lower legs will appear. This symptom can be improved obviously by elevating the affected limb. 2, lower limb venous insufficiency, lower limb venous insufficiency when blood reflux occurs, valve insufficiency leads to increased pressure in the lower limb veins, after the pressure increases, blood return appears significantly restricted, there will also be symptoms of calf weakness, individual patients will also be accompanied by superficial calf vein tortuosity, dilatation. When vascular sink occurs, you can go to the outpatient clinic for ultrasound examination to clarify the cause of vascular sink, whether it is caused by the formation of venous thrombosis or venous insufficiency, and choose the appropriate method of treatment under the guidance of a specialist.