- Buccinator - Compresses cheek against molar teeth
- Frontalis – Elevates eyebrows, pulls scalp anteriorly and wrinkles skin of forehead; eyebrow raising or furrowing
- Orbicularis Oculi – Eyelid closing
- Zygomaticus Major - Elevates and everts angle of mouth; smiling
- Orbicularis Oris - Closes mouth, compresses and protrudes lips
Mechanism of Muscle Weakness in Bell’s Palsy
The facial nerve is damaged by inflammation within the nerve causing it to become enlarged, at the point where the nerve exits the skull through the stylomastoid foramen. Ischemia occurs as the nerve swells in its bony canal, blocking neural blood supply. At onset, the paralysis may be complete, or partial (paresis) and although it frequently affects all branches of the facial nerve on the affected side, resulting in loss of control of that side of the mouth and the ipsilateral eye, in a few cases only one or two branches of the facial nerve are affected.
Other Symptoms
Drooling, increased sensitivity to sound, loss of taste, difficulty in closing the eye