Feeling that the mouth is a little crooked may be central facial palsy or peripheral facial palsy, causing peripheral facial palsy, a common disorder of idiopathic facial nerve palsy. Patients usually show loss of frontal lines on the lesion side, and may also show shallow nasolabial folds on the lesion side, incomplete eyelid closure, and white tympanic membrane may be exposed when eyes are closed, which is clinically known as Bell’s phenomenon, or the corners of the mouth may be skewed to the lesion side, or the wind may be exposed on the lesion side when whistling, etc. Cranial CT examination shows normal. In case of central facial palsy, the common clinical diseases are cerebrovascular diseases, including cerebral hemorrhage and cerebral infarction. Patients with cerebral hemorrhage have a high-density lesion on cranial CT examination, while those with cerebral infarction have a low-density lesion on CT examination. Patients with acute onset of the disease can have a basic symmetry of the frontal lines, a shallow nasolabial fold on the opposite side of the lesion, and a skewed angle of the mouth to the opposite side of the lesion.