Numbness in the legs and feet of the elderly should consider the following diseases: First, lumbar disc herniation, the protruding discs compressing the nerve roots on both sides will appear numbness in the legs and feet. Second, lumbar spinal stenosis, the typical sign of lumbar spinal stenosis is intermittent claudication, walking a few hundred meters will appear numbness and weakness of the legs and feet. To distinguish the above two diseases, go to the hospital to check the lumbar spine CT or MRI of the lumbar spine can be identified. This kind of patients need to check the arterial and venous ultrasound of both lower extremities, and if necessary, CTA will be able to make a differential diagnosis. If an elderly person suddenly develops leg numbness, along with numbness in the ipsilateral upper extremity, it often suggests acute cerebrovascular disease, and a CT or MRI of the head should be done to confirm whether it is an acute cerebral infarction or cerebral hemorrhage.