Weakness of the right arm may be a sign of neurogenic cervical spondylosis, cerebrovascular disease, myasthenia gravis and other diseases, and the cause should be identified in time. 1. Neurogenic cervical spondylosis: After the disease, the nerve roots will be compressed, leading to the weakening of nerve root conductivity, and the patient will show the symptoms of numbness of the limbs, or even the phenomenon of muscular atrophy, in which case the symptom of weakness of the right arm will appear. Doing cervical spine magnetic resonance examination can be clear. 2. Cerebrovascular disease: if the patient suffers from hypertension, diabetes mellitus, suddenly appear right hand weakness, can not make strength, we should consider whether there is acute cerebrovascular disease, need to go to the hospital for examination, clear whether there is cerebral infarction, cerebral hemorrhage and other conditions. 3. Myasthenia gravis: If young and middle-aged patients have weakness of the right arm, limitation in lifting, feeling light in the morning and heavy in the afternoon, or the feeling of weakness of the right arm is aggravated by fatigue, it should be considered whether there is myasthenia gravis, and should go to the hospital for examination in time to clarify the diagnosis. Right arm weakness may also have other causes, the patient should be timely hospital consultation, to clarify the specific causes, and then targeted treatment.