If the symptoms of feeling no strength in the right hand occur suddenly, most of them are considered to be cerebrovascular diseases, mainly seen in small brain hemorrhage on the left side and lacunar cerebral infarction on the left side. Patients may also present with sensory weakness in the right foot and sensory impairment in the right limb. Some patients may have speech dysfunction, including aphasia and dysarthria, and may also have hemianopia or quadrant blindness. If necessary, cranial CT or MRI should be examined to clarify the diagnosis. If the patient has lacunar cerebral infarction, most of the etiology is hypertension and diabetes mellitus. In patients with cerebral hemorrhage, most of them have hypertension or cerebral aneurysm. If necessary, head and neck CTA should be examined to clarify the condition of intracranial blood vessels, and if necessary, surgery can be performed if there is an aneurysm. Patients with lacunar cerebral infarction are mainly treated with aspirin to prevent platelet aggregation, as well as to improve blood circulation and actively control the cause of the patient’s disease.