Muscles affected by Bell's Palsy
- Occipitofrontalis
Action: raises eyebrows and wrinkles forehead horizontally - Orbicularis Oculi
Action: gently closes the eyelids, tightly closes the lids - Orbicularis Oris
Action: closes the lips to narrow the oral opening - Mentalis
Action: elevates, everts and protrudes lower lip, wrinkles skin of chin - Buccinator
Action: maintains the tightness of the cheeks and presses them against the teeth
Mechanism of Muscle Weakness
The nerve that controls facial muscles passes through a narrow corridor of bone on its way to the face. In Bell's palsy, that nerve becomes inflamed and swollen — usually related to a viral infection. Besides facial muscles, the nerve affects tears, saliva, taste and a small bone in the middle of the ear.
Other symptoms patients may exhibit
- Facial droop and difficulty making facial expressions, such as closing your eye or smiling
- Drooling
- Pain around the jaw or in or behind your ear on the affected side
References:
Bell’s palsy - Symptoms and causes - Mayo Clinic. (2022, May 4). Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/bells-palsy/symptoms-causes/syc-20370028#:~:text=The%20nerve%20that%20controls%20facial,the%20middle%20of%20the%20ear.
OpenStaxCollege. (2013, March 6). Axial muscles of the head, neck, and back. Pressbooks. https://pressbooks-dev.oer.hawaii.edu/anatomyandphysiology/chapter/axial-muscles-of-the-head-neck-and-back/
Professional, C. C. M. (n.d.). Bell’s Palsy. Cleveland Clinic. https://my.clevelandclinic.org/health/diseases/5457-bells-palsy
TeachMeAnatomy. (2023, April 9). The muscles of facial expression - orbital group - nasal group - oral group - TeachMeAnatomy. https://teachmeanatomy.info/head/muscles/facial-expression/
Vasković, J., MD. (2023, April 12). Mentalis muscle. Kenhub. https://www.kenhub.com/en/library/anatomy/mentalis-muscle