5 Affected Muscles
1. Frontalis muscle:
Action: Elevates the eyebrows and wrinkles the forehead.
2. Orbicularis oculi:
Action: Closes the eyelids
3. Zygomaticus major:
Action: Elevates the corners of the mouth
4. Orbicularis oris:
Action: Compresses and puckers the lips
5. Buccinator:
Action: Compresses the cheek
Mechanism of Muscle Weakness
Bell's palsy is a condition in which the facial nerve becomes inflamed, compressed, or infected with a virus (usually the Herpes simplex virus), resulting in the temporary paralysis or weakening of the muscles it supplies. When the facial nerve that regulates the expression muscles is damaged, one side of the face loses the ability to move its muscles voluntarily, which can result in paralysis or drooping.
Other Symptoms
Inability to close eye
Difficulty in eating/drinking
Loss of facial expressions
Altered sense of taste
Heightened sensitivity to sound