The majority of people with swollen legs after prolonged sitting and standing are accompanied by venous insufficiency of the lower extremities, because on the basis of venous insufficiency of the lower extremities, prolonged standing and sitting will cause a significant weakening of the muscular pump of the lower legs so that venous reflux is impaired, and the insufficiency of the valves cannot prevent the regurgitation of blood flowing from the feet to the heart. Therefore, these two factors cause blood to stagnate in the veins of the lower extremities, and due to the high pressure in the veins, the fluid content in the veins gradually leaks out and accumulates in the tissues, causing edema in the tissues, which usually requires further ultrasound examination to determine the cause and decide on a treatment plan.