Leg swelling is caused by a variety of reasons, cardiac reasons, renal reasons, vascular reasons, as follows: First, the causes of heart disease is generally considered cardiac insufficiency, in addition to the performance of chest tightness, breath-holding, when the right heart insufficiency, or with pulmonary hypertension, will also cause stasis of the body circulation, resulting in venous reflux in the lower limbs, and visceral reflux disorders, it leads to legs will occur Swelling of the legs. In cardiac causes of swelling, concave edema of the anterior tibial region of the lower leg may occur. Secondly, it is a renal cause. Some people have protein loss due to nephrotic syndrome and chronic kidney disease, and after the protein loss, the plasma osmolarity is changed, resulting in hypoproteinemia and swelling. The swelling often occurs in the lower legs, especially in the front of the shin, but the swelling is concave edema, but it is relatively soft, a bit like pressing on a hair cake, or the feeling of hairy buns, it may be renal, by checking the amount of plasma albumin, total protein is very low, basically can be excluded. There is also a significant increase in urine protein, which is the most common cause of nephrogenic leg swelling. Third, venous edema, venous edema has two causes. The primary venous valve insufficiency is caused by the valve of the vein, which plays the role of a one-way valve, and the reflux of the leg veins is from the low position of the foot to the high position of the heart. There is also a deep vein thrombosis, a condition in which the venous return is blocked due to a thrombus.