The causes of hand numbness include physiological factors, cervical spondylosis, mental illness, carpal tunnel syndrome, cerebrovascular disease and so on. 1. Physiological factors: when the patient lies down to sleep, if the hand is compressed by a certain part of the body, the local ischemia and hypoxia will have numbness symptoms, when the pressure is released, the symptoms can be restored within a few minutes. 2. Cervical spondylosis: When the pillow position is too high during the night sleep, the cervical spine is pulled for a long time, which may induce cervical spondylosis. Due to the compression of the nerve root, the patient will have the symptom of hand numbness. 3. Mental illness: when the patient has anxiety or depression, may consciously have symptoms of hand numbness. The onset of this disease requires antipsychotic treatment under the guidance of psychiatrists. 4. Carpal tunnel syndrome: when the median nerve, which innervates the palmar sensation of the hand, passes through the wrist, the narrow carpal tunnel is pressurized and induced symptoms. Numbness or pain is often felt in all three fingers, and is most severe in the middle finger. Symptoms are most severe at night or early in the morning and can be relieved by shaking the wrist appropriately. 5. Cerebrovascular disease: cerebrovascular diseases such as cerebral thrombosis, cerebral infarction, can start in a quiet state, found in the morning after waking up from sleep, may be manifested as a unilateral numbness of the hand, but often appear on one side of the limbs of the numbness, weakness. There are many factors that cause hand numbness when sleeping flat on the bed, and it is recommended that patients who do not get relief for a long time or who have persistent aggravation should consult a doctor in time to clarify the cause and rationalize the treatment under the guidance of the doctor.