Affected Muscles
- Frontalis: raises the eyebrows, wrinkles forehead
- Orbicularis Oculi: closes eyelides
- Zygomaticus Major: elevates corners of the mouth
- Orbicularis Oris: closes and protrudes the lips
- Buccinator: compresses the cheek
Mechanism of Muscle Weakness
Inflammation or Compression of the facial nerve, which supplies muscles of facial expression leads to weakness experienced when one has Bell's Palsy. As a result, the nerves are unable to transmit signals to the muscles, resulting in paralysis or weakness. Bell's Palsy causes include viral infections (e.g. herpes simplex).
Symptoms
- difficulty closing the eye on the affected side, leading to dryness and irritation
- drooling due to the weakness of the muscles around the mouth
- pain around the jaw or behind the ear on the affected side
- increased sensitivity to sound in one ear
- loss of taste in the front two-thirds of the tongue