The numbness of the feet may be related to poor local blood circulation, lumbar disc herniation, and thromboembolic vasculitis. 1. Poor local blood circulation: the nerves innervating the sensation of the feet are the terminal branches of the sciatic nerve. When the patient crosses his legs, the arteries of the lower limbs and the terminal branch of the sciatic nerve are compressed, and the foot is deprived of blood and oxygen, which leads to the symptom of numbness of the foot. 2. Lumbar intervertebral disc herniation: When the lumbar intervertebral disc undergoes degenerative changes, the fibrous annulus ruptures partially or completely under the action of external force, and protrudes outward alone or together with the nucleus pulposus and cartilaginous endplates, which stimulates or oppresses the terminal branches of the sciatic nerve, thus leading to numbness in the patient’s feet. Crossing the legs will aggravate the symptoms of numbness of the patient’s feet. 3. Thromboembolic vasculitis: Thromboembolic vasculitis is an inflammatory, segmental and recurrent chronic occlusive disease of the blood vessels, when the lower extremity arteries are involved, the foot because of ischemia and hypoxia will lead to numbness of the patient’s feet. If the patient has stilted legs foot numbness symptoms, after adjusting the sitting posture foot numbness symptoms still can not be relieved, the need to go to the hospital in time to improve the relevant examination, clear the cause of the disease, early detection and early diagnosis and treatment.