1.
Muscle: Frontal belly
Action: Draws scalp anteriorly, raises eyebrows, and wrinkles skin of forehead horizontally as in look of surprise.
2.
Muscle: Orbicularis oris
Action: Closes and protrudes lips, as in kissing; compresses lips against teeth; and shapes lips during speech.
3.
Muscle: Orbicularis oculi
Action: Closes eye.
4.
Muscle: Buccinator
Action: Presses cheeks against teeth and lips, as in whistling, blowing, and sucking; draws corner of mouth laterally; and assists in mastication (chewing) by keeping food between the teeth (and not between teeth and cheeks).
5.
Muscle: Platysma
Action: Draws outer part of lower lip inferiorly and posteriorly as in pouting; depresses mandible.
Mechanism:
As stated by Warner et al. (2023) the seventh cranial nerve is believed to be compressed at the geniculate ganglion, which causes bell palsy. The labyrinthine segment, which is the first part of the facial canal, is the narrowest and is where most compression cases take place. Inflammation results in nerve compression and ischemia because the facial canal's opening is so small. A unilateral facial weakness that affects the forehead muscles is the most typical finding.
Other Symptoms:
- sudden facial paralysis or weakness on one side
- a lowered brow and mouth
- one side of your mouth is drooling
- Having trouble closing your eyes leads to dry eyes.
They could also develop:
- abnormal feelings or facial pain
- one eye is tearing a lot.
- issues with flavor
- sensitivity to loud noises
- Pain behind the ear and in the area of the jaw
- eating or drinking issues
References:
National Institute of Neurological Disorders and Stroke. (n.d.). Bell’s Palsy. Bell's Palsy | National Institute of Neurological Disorders and Stroke (nih.gov)
Tortora, G. J., & Derrickson, B. (2017). Principles of anatomy & physiology. Fifteenth edition; Wiley Loose-Leaf Print Companion. Hoboken, New Jersey, John Wiley & Sons, Inc.