Why the patient’s arm will be numb is mainly related to the involvement of the arm’s nerves, and the numbness of the arm occurs when the arm is pressed, which is mainly seen in two ways: firstly, when the head is lying on the front and compresses the median nerve and radial nerve, it is easy to appear that there is a decrease in sensation on the skin of the anterior side of the arm, the thumb of the palm, the forefinger, the middle finger, the ring finger, and the radial side of the skin. Secondly, if the hand is backward, the head is easy to compress the ulnar nerve, and there will be numbness in the inner side of the forearm, the small fissure, the little thumb and the index finger, and there will be limitation of finger movement. Hand pressure on the arm numbness is mainly seen in the front of the ambulance or the back of the pillow, it is easy to appear after the arm nerve damage numbness symptoms.