Numbness of the legs may be caused by cervical spondylosis, lumbar intervertebral disc herniation, cerebrovascular lesions and other factors. 1. Cervical spondylosis: prolonged and excessive bowing of the head may induce cervical spondylosis, which may lead to numbness in one or both lower limbs with a feeling of heaviness when the spinal cord is compressed, and in severe cases, it may lead to movement disorders and urinary and fecal incontinence. 2. Lumbar disc herniation: it may be related to acute injury or degenerative changes, which can lead to compression of the nerves innervating the lower limbs, causing numbness in the legs and lower limbs, and may be accompanied by radiating pain in the lower limbs, lumbar pain and other symptoms. 3. Cerebrovascular lesions: If there is a sudden numbness of the legs unilaterally, accompanied by numbness of the upper limbs, dizziness, headache and other symptoms, we should be alert to cerebrovascular lesions, such as acute cerebral infarction or acute cerebral hemorrhage. Numbness of the legs, lasting for a long time, it is recommended to consult a doctor for the appropriate examination, to clarify the specific causes, and timely treatment.