Numbness of legs in the elderly may be lumbar disc herniation, pyriformis syndrome, cerebrovascular disease, lower extremity arterial stenosis, diabetic neuropathy, etc.. 1. Lumbar disc herniation is caused by degeneration of lumbar vertebrae, osteophytes, and herniated intervertebral discs compressing the nerves, resulting in numbness and pain in the lower limbs, and in severe cases, patients may suffer from walking claudication. 2. Piriformis syndrome is due to the strain of the piriformis muscle spasm compression of the sciatic nerve numbness of the lower limbs, usually in the back of the leg, and accompanied by symptoms of pain. 3. Cerebrovascular disease, such as cerebral infarction, cerebral hemorrhage, the onset of sudden numbness of the lower limbs, lower limb activity is unfavorable, through the head CT can be clear. 4. Lower extremity arterial stenosis, such as thromboembolic vasculitis, can cause lower extremity blood supply is insufficient to cause numbness of the legs, and some may have cold limbs. 5. Diabetic neuropathy, belonging to the complications of diabetes, lower limb numbness, abnormal sensation, such as ants, burning sensation. If the elderly leg numbness persists unrelieved need to go to the hospital in time for examination.