Activity 4
- Muscles affected by Bell's palsy:
- Occipitofrontalis, frontal belly - Draws scalp anteriorly, raises eyebrows, and wrinkles skin of forehead horizontally, as in look of surprise
- Orbicularis oris - Closes and protrudes lips, as in kissing; compresses lips against teeth; and shapes lips during speech
- Zygomaticus major - Draws angle of mouth superiorly and laterally, as in smiling
- Risorius - Draws angle of mouth laterally, as in grimacing
- Buccinator - 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)
- Mechanism of muscle weakness:
- Bell's palsy develops when the seventh cranial nerve, that regulates the facial muscles, becomes inflamed and swollen. The muscles on one side of the face are affected when one of the two facial nerves becomes inflamed. However, many occurrences of Bell's palsy are idiopathic, meaning they lack a known cause. Some illnesses (such as viral infections) may also produce inflammation.
- Other symptoms as a result of facial muscle weakness:
- Unusual sensations, including facial pain
- Excessive tearing in one eye
- Gustatory issues
- Heightened sensitivity for loud noises
- Tinnitus or ringing in the ears
- Difficulty in speaking, eating or drinking
References:
Bell’s Palsy. (2023). Cleveland Clinic. https://my.clevelandclinic.org/health/diseases/5457-bells-palsy
Bell’s Palsy. (2023). National Institute of Neurological Disorders and Stroke. https://www.ninds.nih.gov/health-information/disorders/bells-palsy
Tortora, G. J., & Derrickson, B. H. (2017). Tortora’s Principles of Anatomy & Physiology. Wiley.