The leg numbness is mainly due to leg muscles, nerves, vascular tissue compression, usually a transient physiological phenomenon, very few cases are pathological factors. 1, the physiological situation: a long time to maintain a sitting posture coupled with extreme flexion of the knee joint, the leg gastrocnemius muscle and its surrounding tissues will be compressed, resulting in slow blood flow, slowing the local nerve conduction, then the compressed parts will feel hypoesthesia, numbness, pins and needles. Numbness and pins and needles sensation. Leg numbness symptoms, should promptly change the sitting position, you can stand up and move a little, so that the blood circulation in the legs again smooth; can also lie down, gently massage the numb parts, accelerate blood circulation, relieve numbness; 2, pathological conditions: some motor system diseases, such as lumbar disc herniation, pear-shaped muscle syndrome, or local thrombosis, tumor compression of the nerves innervating the legs, especially when sitting cross-legged compression More obvious, it can lead to leg numbness, accompanied by pain in the lumbar region or hip and leg, or even unable to walk because of too much pain. Most leg numbness caused by disease is accompanied by other symptoms and should be distinguished.