The most common factor is orthopedic surgery, usually due to lumbar disc herniation, lumbar disc bulge, sacroiliac arthritis or sciatic nerve injury will cause numbness of the nerve roots innervating the lower leg, which will lead to symptoms of swelling of the leg belly. 2, in the case of cardiac decompensation, renal decompensation and other diseases, the inability to transport water in a timely manner causes sodium and water retention in the body. In severe infections, especially in septic shock, the arteriovenous short-circuit and direct pathway will be opened, and the clinical symptoms and performance of swelling and edema in the lower extremities will appear. 4. Excessive exercise leads to the accumulation of lactic acid in both lower limbs, which can also cause swelling of the leg belly.