Sudden numbness in the arms may be caused by the following reasons: first, cervical spondylosis, cervical spondylosis can appear when the nerve roots are compressed, the symptoms of numbness in the arms, to take cervical spine X-ray, CT, nuclear magnetic examination, to early diagnosis and early treatment. The second cause is myofasciitis, myofasciitis is often the first symptom of pain on the inner side of the scapula, can be radiated to the ipsilateral upper limb, appearing soreness, numbness, weakness, especially during exertion and sleep pressure at night, numbness is more obvious, to early examination and examination, to exclude other diseases to early diagnosis and early treatment. Thirdly, head diseases, when there is a tumor pressing on the nerve in the head, the symptoms of numbness in the arm can also appear, and the head MRI should be checked for early diagnosis and treatment.