Affected muscles:
- Frontalis - elevates the eyebrows and wrinkles the forehead.
- Orbicularis oculi - closes the eyelids, responsible for blinking and squinting.
- Platysma - pulling down the mandible, opens the mouth, and pulling the corners of the lips
- Orbicularis oris - loses and puckers the lips
- Buccinator - compresses the cheek
Mechanism of Muscle Weakness:
Bell's palsy is a disorder that results in unilateral facial paralysis, or an abrupt weakness of the muscles on one side of the face. It happens when the 7th cranial nerve becomes inflamed, which is typically brought on by viral infections like Lyme disease and HIV. As the nerve travels through the small facial canal in the skull, inflammation causes compression and temporary damage, impairing muscle contraction and resulting in leading facial droop on the afflicted side.
Other symptoms:
- Decreased tearing
- Aching of the ear
- Drooling due to weakness of the muscles around the mouth
- Tingling or numbness of cheek or mouth
- Increased sensitivity to sound (hyperacusis)