When the tongue is stretched out, the tip of the tongue is tilted to one side, either left or right, which is called tongue distortion. When the tongue muscle on the sick side is paralyzed, it is unable to contract, and when it is slightly extended, the tongue body is unevenly skewed on both sides, so the tip of the tongue is to the left when the left tongue muscle is paralyzed, and to the right when the right tongue muscle is paralyzed. This condition is commonly associated with stroke, i.e. cerebrovascular accident. Differential diagnosis of tongue muscle palsy: Facial nerve palsy (facial neuritis, Bell’s palsy, Hunter’s syndrome): commonly known as “facial palsy”, “crooked mouth”, “crooked mouth”, “hanging line wind”, “crooked mouth”, “crooked mouth”, “hanging line wind”, “hanging slant wind”, “facial neuritis”, “crooked mouth wind”, etc., is a kind of facial expression muscle group It is a common disease mainly characterized by motor dysfunction of facial expression muscle groups, and the general symptom is crooked mouth and eyes. It is a common and frequent disease, which is not limited by age and gender. The patient’s face is often unable to perform even the most basic movements such as raising the eyebrows, closing the eyes, puffing the cheeks and nudging the mouth. Stroke (apoplexy): It is a disease with sudden fainting and unconsciousness, accompanied by distorted mouth, unfavorable speech and hemiplegia, or only distorted mouth and hemiplegia without fainting as the main clinical symptoms. Because of the rapid onset, multiple symptoms, and rapid changes in the condition, the disease is similar to the characteristics of wind, hence the name stroke. The morbidity and mortality of the disease are high, and there are often sequelae; the incidence has been increasing in recent years, and the age of onset tends to be younger, so it is a major disease that threatens human life and quality of life. In addition to the facial nucleus and the hypoglossal nucleus, which innervate the inferior facial muscles unilaterally (contralaterally), all other cerebral nerve motor nuclei receive fibers from bilateral cortical nuclei bundles. Damage to the upper motor neurons on one side may produce paralysis of the facial muscles below the fissure of the eye and the tongue muscles on the opposite side of the lesion, manifested by loss of the nasolabial groove on the opposite side of the lesion, drooping of the corners of the mouth and deviation to the side of the lesion, salivation, inability to perform cheek puffing and tooth exposure, and deviation of the tongue tip to the opposite side of the lesion when extending the tongue. In case of peripheral facial nerve palsy on one side, all facial muscles on the side of the lesion can be paralyzed, manifested as loss of frontal transverse lines, inability to close the eyes, drooping of the corners of the mouth and loss of the nasolabial folds. Damage to the motor neurons under the hypoglossal nerve on one side may result in paralysis of all the tongue muscles on the focal side, manifested by a deviation of the tongue tip to the focal side when extending the tongue. In individual cases of peripheral facial nerve palsy, a deviation of the tongue may be seen, in which case the tongue is always deviated to the healthy side. This is due to paralysis of the caudate and palatoglossus muscles innervated by the facial nerve.