Numbness of the right arm may be caused by improper sleeping posture, cervical spondylosis, carpal tunnel syndrome, elbow tube syndrome and so on. 1. Improper sleeping position: If the arm is compressed while sleeping, the blood circulation in the arm is not smooth, thus causing numbness in the right arm. 2. Cervical spondylosis: when the cervical intervertebral disc degenerative changes, so that the soft tissues of the neck and vertebral body movement disorder, resulting in irritation or compression of the cervical nerve root, causing numbness in the right arm. 3. Carpal tunnel syndrome: If there is exogenous compression, the carpal tunnel becomes small, the canal lumen occupies the position of the influence of other factors, sometimes carry out frequent, repeated force, and then cause the right arm numbness. 4. Elbow canal syndrome: If the ulnar nerve is compressed by tendon membrane, abnormal muscle or bony changes at the elbow through the ulnar nerve groove, resulting in numbness of the right arm, accompanied by tingling or aching sensation. It is recommended to go to the hospital in time, under the diagnosis of the doctor, according to the specific performance of the patient’s condition, targeted treatment, so as not to affect the body.