The numbness of the instep may be caused by physiological reasons such as standing, squatting for too long, inappropriate shoes, etc., or it may be due to diabetes, lumbar disc herniation and other pathological factors. 1. Physiological reasons: the dorsum of the foot belongs to the peripheral parts of the body, itself due to centrifugal farther, blood circulation is relatively poor compared to other parts of the body, if a long period of time standing or squatting time is too long, it will lead to transient dorsum of the foot circulatory disorders, resulting in the dorsum of the foot numbness of the symptom; in addition, if the shoes are not suitable, the activities of the process of the long cradle, it may also be the case of the above symptom. 2. Pathological factors: the body’s sugar metabolism abnormalities may cause the emergence of diabetes mellitus, diabetes can cause peripheral nerve sugar supply disorders, resulting in peripheral nerve ischemia, hypoxia peripheral nerve lesions may also occur; lumbar intervertebral disc herniation may be innervating the dorsal part of the foot of the nerves caused by the cardiac compression, may also occur the above symptoms. Numbness of the back of the feet may also have other reasons, it is recommended to go to the hospital in a timely manner, improve the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.