Affected muscles and their actions:
- Orbicularis Oculi: Closes the eyelids, blinking
- Orbicularis Oris: closes, protrudes and compresses the lips
- Buccinator: contraction pulls the corner of the mouth laterally
- Frontalis: Elevates the eyebrows
- Platysma: depresses mandible
Mechanism of muscle weakness:
Bell's Palsy is a facial muscle weakness or paralysis caused by damage to the facial (VII) nerve, which arises from conditions like viral infection, or a bacterial infection. Infections may cause the inflammation of the 7th cranial nerve, and this leads to compression and temporary nerve damage. This disables muscle contraction, leading to drooping of the face
Other Symptoms:
- Drooling
- Pain in your jaw or behind your ear
- Headache
- Less sense of taste
- Dry eye and mouth
- Ringing in your ears (tinnitus)
- Low tolerance for loud sounds (hyperacusis)
- Difficulty talking