Patients with numbness in the left hand and foot, if they appear suddenly, should be considered to be caused by acute cerebrovascular disease, such as cerebral arteriosclerosis, cerebrovascular stenosis caused by cerebral thrombosis, or lacunar cerebral infarction or cerebral embolism disease, which are all ischemic cerebrovascular diseases. There are also minor cerebral hemorrhages, such as in the thalamus, that can cause numbness in the patient’s left hand and left foot. If the patient is active when the disease starts to consider the above problems, it can be clarified by doing head CT, head MRI, and functional brain imaging. If the numbness in the left hand and foot appears slowly and lasts for a long time, gradually progressing and worsening, it may be caused by intracranial tumor or occupancy causing sensory and neurological damage, which can also be clarified by CT and MRI of the head.