For the causes of right hand muscle weakness, it is as follows: first, trauma: if the right hand is weak, and it is manifested as distal weakness, it is necessary to ask the patients whether they have suffered from trauma or whether the cervical spine is injured, and it is necessary to do cervical spine magnetic resonance examination to find out whether there is any cervical vertebrae compressive lesion. Second, acute cerebrovascular disease: patients should be asked whether there is weakness of the right upper limb, dizziness, weakness of the right lower limb, and cranial CT and magnetic resonance examinations are needed to find out whether there is acute cerebrovascular disease, such as cerebral infarction and cerebral hemorrhage. Third, motor neuron disease and demyelinating disease: to observe whether there is muscle atrophy of the right hand and weakness of the left hand, electromyography as well as cranial and cervical magnetic resonance examination should be carried out to find out whether there is motor neuron disease. Also, be alert for demyelinating diseases.