5 Affected Muscles
Frontalis
Action: Elevation of the eyebrows; wrinkles the forehead
Orbicularis Oculi
Action: Closes the eyelids (i.e., blinking, protecting the eye)
Platysma
Action: Pulling down the mandible; opening of the mouth; pulling the corners of the lips
Orbicularis Oris
Action: Closes and puckers the lips (e.g., speech, blowing, and eating)
Buccinator
Action: Cheek compression (e.g., chewing, preventing food from accumulating between the cheeks and teeth)
Mechanism
Inflammation/viral infection makes the facial nervcompress e as it travels through the canal in the facual bone. This affects the motor signals to the muscles of facial expression, leading to unilateral paralysis and makes the facual muscles weak. It mskes the face droop as they have no more control.
Other Symptoms
Inability to close the eye
Inability to raise the eyebrow
Drooling
Speech difficulties
Hyperacusis