5 Muscles affected by Bell’s Palsy & its actions
1. Occipitofrontalis
Action: Elevates and protrudes lower lip and pulls skin of chin up, as in pouting.
2. Orbicularis Oculi
Action: Closes eye.
3. 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).
4. Mentalis
Action: Elevates and protrudes lower lip and pulls skin of chin up, as in pouting.
5. Plantysma
Action: Draws outer part of lower lip inferiorly and posteriorly as in pouting; depresses mandible.
Mechanism of his muscle weakness
Bell’s palsy, which can also be called facial paralysis, primarily affects the muscles of facial expression. This condition may occur due to damage or disease in the facial (VII) nerve like inflammation in the aforementioned nerve caused by ear infection, ear surgery that may have affected or injured the facial nerve, or infection brought by viruses such as herpes simplex virus. With Bell’s Palsy, the entire side of a patient’s face droops. In line with this, the patient will experience an inability to wrinkle the forehead, close his eye, pucker his lips on the affected side, and even have difficulty in swallowing.
Other symptoms that may be exhibited as a result of facial muscle weakness:
- Aphasia (difficulty with or loss of speaking ability)
- Blurred or double vision (diplopia)
- Neck stiffness
- Drooling
- Changes in the amount of tears and saliva you produce
- Problems smiling, grimacing, or making facial expressions
- Twitching or weakness of the muscles in the face
References:
Bell’s Palsy. Cleveland Clinic. (n.d.). https://my.clevelandclinic.org/health/diseases/5457-bells-palsy
Campellone, J. V., & Dugdale, D. C. (n.d.). Pennmedicine.org. https://www.pennmedicine.org/for-patients-and-visitors/patient-information/conditions-treated-a-to-z/bells-palsy
Tortora, G. J., & Derrickson, B. (2017). Principles of anatomy and physiology. Wiley Custom Learning Solutions.
U.S. Department of Health and Human Services. (n.d.). Bell’s Palsy. National Institute of Neurological Disorders and Stroke. https://www.ninds.nih.gov/health-information/disorders/bells-palsy