This is patient AM, 28-year-old male who came in the ER because of drooping of his left face. He said he woke up and he could not move his left face.
He has no other muscle weakness. He is conscious and coherent although he had a little difficulty speaking because the left side of his lips drooped. He had normal blood pressure and he had no other co-morbidities. He was diagnosed to have Bell’s palsy. Name 5 muscles which are affected and list its actions. Describe the mechanism of his muscle weakness. What other symptoms could the patient exhibit as a result of facial muscle weakness?
Patient: 28-year old male, normal and no other co-morbidities
The mechanism of Bell's Palsy:
This is a condition of the facial nerve that affects how the person's facial muscles move. The facial nerve, or seventh cranial nerve, is damaged, these muscles will become weakened or paralyzed. One of the nerves that controls muscles in your face becomes injured or stops working properly. The first portion of the facial canal, the labyrinthine segment, is the narrowest; most cases of compression occur in the labyrinthine segment. Due to the narrow opening of the facial canal, inflammation causes compression and ischemia of the nerve.
Muscles affected by Bell's Palsy:
1. 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).
2. Orbicularis oris
Action: Closes and protrudes lips, as in kissing; compresses lips against teeth; and shapes lips during speech.
3. Orbicularis oculi
Action: Closes eye.
4. Platysma
Action: Draws outer part of lower lip inferiorly and posteriorly as in pouting; depresses mandible.
5. Occipitofrontalis (frontal belly)
Action: Draws scalp anteriorly, raises eyebrows, and wrinkles skin of forehead horizontally as in look of surprise.
Other symptoms of Bell's Palsy:
- Sudden weakness or paralysis on one side of your face
- A drooping eyebrow and mouth
- Drooling from one side of your mouth
- Difficulty closing an eyelid, which causes eye dryness
References:
Bell's Palsy. (n.d.). National Institute of Neurological Disorders and Stroke. https://www.ninds.nih.gov/health-information/disorders/bells-palsy#toc-what-is-bell-s-palsy-
Penn Medicine. (n.d.). Bell's Palsy - Symptoms and Causes. https://www.pennmedicine.org/for-patients-and-visitors/patient-information/conditions-treated-a-to-z/bells-palsy#:~:text=Bell%20palsy%20is%20a%20disorder,use%20the%20muscles%20at%20all
Tortora, G. J., & Derrickson, B. H. (2017). Principles of Anatomy and Physiology (15th ed.). Wiley. Retrieved from https://handoutset.com/wp-content/uploads/2022/05/Principles-of-anatomy-and-physiology-Wiley-2017-Derrickson-Bryan-H._-Tortora-Gerard-J..pdf.
Warner, M. J., Hutchison, J., & Varacallo, M. (2022, September 4). Bell palsy - StatPearls - NCBI bookshelf. National Center for Biotechnology Information. https://www.ncbi.nlm.nih.gov/books/NBK482290/