- Orbicularis oculi: Controls the closure of the eyelids (blinking and squinting)
- Orbicularis oris: Controls the movements of the lips (puckering and closing the mouth)
- Zygomaticus major: Lifting the corners of the mouth to smile
- Buccinator: Blowing air and keeping the cheeks taut
- Risorius: Smiling and retracting the corners of the mouth laterally.
Mechanism of muscle weakness
- This is caused by the inflammation or compression of the facial nerve. This disrupts the signals sent from the brain to these facial muscles so the affected muscles do not receive the appropriate nerve impulses. This leads to weakness or paralysis on one side of the face.
Other symptoms
- Difficulty closing the eye on the affected side which can lead to dryness, irritation, and reduced protection of the eye.
- Due to impaired drainage of tears, the affected eye may become watery.
- Taste sensation on the front two-thirds of the tongue may be affected leading to an altered sense of taste
- Some individuals may experience heightened sensitivity to loud noises (Hyperacusis).