The 4㎜ widening of the temporal horn of the right lateral ventricle may be epileptic foci, which needs to be analyzed with the patient’s specific situation. Epilepsy is a chronic common disease of the nervous system caused by a variety of etiological factors, characterized by excessive discharges of neurons in the brain in the form of recurrent, episodic, transient malfunction of the central nervous system, and cranial magnetic resonance examination is an important means of detecting epileptic foci. When patients present with temporal lobe epileptic foci, it can lead to atrophy of the temporal lobe, so it can cause widening of the temporal horn of the right lateral ventricle. Widening of the temporal horn of the right lateral ventricle by 4㎜ may also be caused by hydrocephalus and ischemic-hypoxic encephalopathy. To summarize, 4㎜ widening of the temporal horn of the right lateral ventricle may be an epileptic foci, and the details of the case should be further examined and treated under the guidance of the doctor according to the patient’s symptoms and signs and symptoms.