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Central facial palsy (colloquially referred to as central seven) is a symptom or finding characterized by paralysis or paresis of the lower half of one side of the face. It usually results from damage to upper motor neurons of the facial nerve. The facial motor nucleus has dorsal and ventral divisions that contain lower motor neurons supplying the muscles of the upper and lower face, respectively. The dorsal division receives bilateral upper motor neuron input (i.e. from both sides of the brain) while the ventral division receives only contralateral input (i.e. from the opposite side of the brain). Thus, lesions of the corticobulbar tract between the cerebral cortex and pons and the facial motor nucleus destroy or reduce input to the ventral division, but ipsilateral input (i.e. from the same side) to the dorsal division is retained. As a result, central facial palsy is characterized by hemiparalysis or hemiparesis of the contralateral muscles of facial expression, but not the muscles of the forehead. ==Signs and symptoms== Central facial palsy is the paralysis of the lower half of one side of the face. This condition is often caused by a stroke. This condition is often the result of damage of the upper motor neurons of the facial nerve. The facial motor nucleus contains ventral and dorsal areas that have lower motor neurons that supply the upper and lower face muscles. When central facial palsy occurs, there are lesions in the corticobulbar tract between the cerebral cortex. Because of these lesions, the facial motor nucleus will reduce or destroy input in the ventral division. The ipsilateral input in the dorsal region is preserved. Central facial palsy is often characterized by either hemiparalysis or hemiparesis of the contra-lateral muscles in facial expression.〔 〕 Muscles on the forehead are left intact. Also, most patients will have lost voluntary control of the movement of the muscles in the face, however, the muscles in the face that are involved in spontaneous emotional expression will often remain intact.〔 Central Facial palsy occurs in patients who are hemiplegic. Such patients not only have dysfunctions in the facial expression but also a difficulty in communication. Other oropharyngeal functions such as sucking, swallowing, and talking are also impaired.〔 Central facial paralysis/palsy often has similar characteristics with stroke patients. Because of uncrossed areas from the ipsilateral and the supranuclear areas, movements in the frontalis and upper orbicularis oculi are often spared.〔 Facial movement can be present on the affected side when the person expresses emotion. Damage to the central nervous system motor pathway from the cerebral cortex to the facial nuclei is found in the pons. This will lead to facial weakness that will spare various muscles in the face depending on the type of paralysis. The discrepancy of the weakness between the upper and lower facial muscles are due to the bilateral corticonuclear innervation from the upper facial muscles and contralateral corticonuclear innervation to the lower facial muscles. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Central facial palsy」の詳細全文を読む スポンサード リンク
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