Muscles affected by Bell's palsy:
1. Occipitofrontalis - draws scalp anteriorly, raises eyebrows, and wrinkles skin of forehead horizontally as in look of surprise.
2. Orbicularis oculi - closes the eye.
3. Zygomaticus major - draws angle of mouth superiorly and laterally, as in smiling.
4. Orbicularis oris - closes and protrudes lips, as in kissing; compresses lips against teeth; and shapes lips during speech.
5. Buccinator - Presses cheeks against teeth and lips, as in whistling, blowing, and sucking; draws corner of mouth laterally; and assists in mastication by keeping food between the teeth.
Mechanism of Muscle Weakness:
Disruption of the facial nerve's ability to transmit signals can lead to weakness or paralysis in the affected muscles.
Other symptoms:
- Drooping eyelid and/or mouth in the affected side of the face
- Inability or difficulty to close the eye in the affected side
- Loss of taste in affected regions of the tongue
- An increased sensitivity in the ear of the affected side due to the disability of the stapedius muscle in the ear