The sunken leg is mainly considered from three aspects: nerve, blood vessel and muscle. The nerve condition is mainly lumbar spinal stenosis, when the lumbar spinal stenosis, the nerves of the spinal cord will be compressed, and thus the patient will have symptoms of sinking legs. In the case of arterial occlusion, when there is arterial occlusion in the lower limbs of the patient, there will also be sinking of the legs after walking. Because when the patient is walking, the muscle movement of the lower extremity needs a lot of oxygen, and when the blood vessel is occluded, it is difficult to transport oxygen to the blood vessels of the lower extremity through the artery, so the patient will have pain in the lower extremity and lack of blood and oxygen, so the patient will have sunken legs. When the patient has varicose veins in the lower extremities, it will also cause restricted venous return, which will cause significant bruising in the lower legs when walking for a long time and will also lead to sinking of the lower legs. There is also the case of damaged calf muscles or cold, which will also lead to wrinkled and stiff calf muscles, so there will also be sunken calves when standing.