Leg numbness and buttock pain, consider lumbar disc herniation, pyriformis syndrome, lumbar spinal stenosis and so on. 1. Lumbar disc herniation: lumbar disc herniation is a degeneration of the lumbar disc, which leads to rupture of the disc and herniation of the nucleus pulposus under the effect of exertion and trauma, which will compress the sciatic nerve to cause pain, and the pain is usually radiating from the buttocks along the back of the thighs to the calves and the back of the feet. 2. Piriformis syndrome: Piriformis syndrome is considered to be caused by trauma to the buttocks, bleeding and adhesion to form scars, resulting in hypertrophy of the piriformis muscle and compression of the sciatic nerve, the main manifestation is pain on the affected side of the buttocks, and the pain radiates along the sciatic nerve to the thighs and calves. 3. Lumbar spinal stenosis: lumbar spinal stenosis is congenital lumbar spinal canal underdevelopment or acquired factors such as lumbar spinal canal stenosis, the spinal canal is the spinal cord nerve protection, but if the spinal canal stenosis will be compressed to the nerves, will also cause a series of symptoms, if the compression of the sciatic nerve will cause sciatic pain, manifested as numbness of the legs buttock pain. It is recommended to go to the hospital for a detailed examination of the cause of the numbness of the legs and buttock pain, in order to treat the cause of the disease.