5 Muscles Affected by Bell's Palsy and Their Actions
1. Orbicularis oris - closes and protrudes the lips (kissing), compresses lips, helps in shaping lips during speech
2. Orbicularis oculi - closes the eye
3. Frontalis - raises eyebrow and wrinkles skin of the forehead
4. Buccinator - presses cheeks against teeth and lips, helps in chewing
5. Zygomaticus major - pulls the corners of the mouth superiorly and laterally
Mechanism of Muscle Weakness
When a patient has Bell's palsy, their facial nerve is inflamed, impairing its ability to send signals to the facial muscles. This leads to weakness or paralysis, evident in the drooping of one side of the face. The exact cause of inflammation is not always known, but it is believed to be associated with viral infections or immune responses.
Other Symptoms Due to Facial Muscle Weakness
1. Unable to close the eye
2. Loss of facial expression
3. Increased sensitivity to sound
4. Mouth drooping
5. Difficulty in chewing and swallowing
6. Difficulty in talking