Legs are always numb mainly consider the following causes: a. If the patient is numbness in both legs, mainly in both calves, with garter-like shallow sensory loss, ask the patient if he has diabetes. Some diabetic patients with diabetic peripheral neuropathy mainly show numbness in both legs, mainly in the calves, and can go to the hospital for electromyography and blood glucose measurement. Second, if it is mainly numbness in one leg, manifested as numbness in the lateral calf or the back of the thigh, ask the patient if there is any lumbar pain or discomfort in the hip muscles, consider that the patient may have lumbar disc herniation and need to go to the hospital for lumbar spine MRI examination. Third, to ask the patient whether there is a past history of long-term alcohol consumption, some patients who have been drinking alcohol for a long time can easily cause vitamin absorption disorders, manifesting as subacute joint degeneration and manifesting as numbness in both legs, also accompanied by leg weakness, walking with a cotton-like feeling, need to go to the hospital to do electromyography and vitamin B1, vitamin B12 determination. Fourth, also consider whether the patient has vertebral occupational lesions, such as thoracic or cervical spine tumors, need to go to the hospital to do magnetic resonance examination of the thoracic or cervical spine.