Muscles affected and their actions
- frontalis: draws scalp anteriorly, raises eyebrows, and wrinkles skin of forehead horizontally
- orbicularis oculi: closes eye
- orbicularis oris: closes and protrudes lips; compresses lips against teeth; and shapes lips during speech
- buccinator: presses cheeks against teeth and lips; draws corner of mouth laterally; assists in mastication by keeping food between the teeth.
- platysma: draws outer part of lower lip inferiorly and posteriorly; depresses mandible.
mechanism for muscle weakness
an inflammation due to infection in the facial nerve (VII) compresses the nerve through the facial canal which it passes through. This disrupts the neuromuscular transmissions to the affected muscles, ultimately weakening or paralyzing them.
other symptoms
drooling, loss of sense of taste, inability to eat and drink, hypersensitivity in affected ear