Arm numbness can be caused by many reasons, such as brain tumor, cerebrovascular disease, compression of cervical nerve root, or axillary nerve injury, elbow tube syndrome and so on. 1. Factors of brain diseases: when the central back of the brain produces tumors or hemorrhage, etc., it is easy to gradually compress and stimulate the sensory nerves, and eventually show the phenomenon of arm numbness, and many of them are accompanied by headache and dizziness, and even accompanied by hemiparesis of some limbs. 2. Neck disease factors: some patients because of cervical spondylosis compression of nerve roots, resulting in numbness of the arm pain and discomfort, and even serious cases will cause the phenomenon of lifting can not be lifted, and the vast majority of the accompanying neck pain and discomfort. 3. Factors of upper limb diseases: some patients may suffer from trauma caused by ulnar nerve injury or long-term incorrect posture, resulting in elbow tube syndrome, which may also cause numbness and discomfort in the arm. Clinical examination can be carried out to clarify. It is recommended to go to the hospital in time to carry out the relevant examination, so as to be able to better clarify the cause of the disease.