Central facial palsy

Central facial palsy
Classification and external resources
Specialty	neurology
ICD-10	G51.g
ICD-9-CM	351
[]

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 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.

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 reduces or destroys input in the ventral division. The ipsilateral input in the dorsal region is preserved.

...
Wikipedia