Numbness in the arm at night indicates that the nerve is being compressed. One situation is due to a posture for too long, the numbness caused by compression of the nerve, the nerve itself is not a problem, lifting the compression of the position, the numbness naturally disappears. Another situation is that the nerve itself has been compressed in the body, forming a nerve jam, and the nerve compression is caused by the reduction of limb activity during sleep, with obvious symptoms, often manifesting as numbness in the hand or forearm, such as carpal tunnel syndrome or elbow tunnel syndrome. Carpal tunnel syndrome is numbness of three fingers on the thumb side of the fingers, elbow tunnel syndrome is numbness of the little finger, and sometimes the forearm can also be very uncomfortable, and can wake up numb when sleeping, and the numbness will gradually decrease after shaking the hand or straightening the elbow joint. This condition is recurrent and should be diagnosed by electromyography, and surgery is required for severe symptoms. If numbness occurs above the elbow joint and is frequent, it may be caused by cervical spine degeneration compressing the nerve, so cervical spine X-ray and MRI should be taken to confirm the diagnosis. In addition to the diagnosis of recurrent numbness, nerve-nourishing treatment should be actively administered, including oral methylcobalamin or intramuscular adenosylcobalamin.