The Affected Muscles
1. Frontalis
Action: Elevation of the eyebrows and wrinkles the forehead
2. Orbicularis Oculi
Action: Closes the eyelids like blinking of the eye and protecting the eyeball
3. Platysma
Action: Pulling down the mandible, opening of the mouth, and pulling the corners of the lips
4. Orbicularis Oris
Action: Closes and puckers the lips like talking, blowing, and eating
5. Buccinator
Action: Activities involving cheek compression like chewing, preventing food from between the cheeks and teeth
Mechanism
When inflammation or a viral infection puts pressure on the facial nerve as it moves through the facial canal in the temporal bone, it can interfere with the nerve’s functioning. This disrupts the signals that control the facial muscles, causing weakness or paralysis on one side of the face. Since the facial nerve controls all the muscles used for expression, this damage often leads to a noticeable droop on the affected side with the inability to express expressions through the face.
Other Symptoms
- Inability to close the eye
- Inability to raise the eyebrow
- Uncontrollable drooling
- Speech difficulties
- Hyperacusis