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.
Frontal Belly
Involved in raising the eyebrows and wrinkling the forehead. In addition, it also draws the scalp anteriorly
Orbicularis Oculi
Closes the eye and eyelids, and aids the passage of tears
Orbicularis Oris
Known as the “kissing” muscle, it closes and pushes the lips forward. It also compresses the lips against the teeth, and shapes it during speech.
Buccinator
Famously known for its role in assisting mastication by keeping food between the teeth. It also enables us to whistle, blow, and suck by pressing the cheeks against the teeth and the lips. Lastly, it laterally draws the corner of the mouth as well.
Platysma
The muscle depresses the mandible, and inferiorly and posteriorly draws the outer part of the lower lip.
Describe the mechanism of his muscle weakness.
Bell’s palsy is recognized as “facial paralysis,” wherein the muscles of the face are paralyzed due to the inflammation and damage of their innervation: the facial (VII) nerve. As such, this condition restricts muscles from voluntary movement and function. For instance, an individual experiencing Bell’s palsy may experience an inability to close their eyes, pucker their lips, and express emotions through their face.
In the case of AM, the muscle weakness, difficulty speaking, and “droopiness” of his left face is brought about by the paralysis of his facial muscles.
What other symptoms could the patient exhibit as a result of facial muscle weakness?
Symptoms of Bell’s palsy are similar to those of stroke.
Other symptoms may include:
Drooling for the left side of his mouth
Inability to blink or close his eyes (even if sleeping)
Difficulty in swallowing
Unable to wrinkle forehead, pucker lips, or voluntarily moving the face
Difficulty expressing emotions via facial expressions
References:
Bell’s Palsy. (2022). UCL Queen Square Institute of Neurology. https://www.ucl.ac.uk/ion/library/links/patients/z/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. (2017). Principles of Anatomy & Physiology. http://ndl.ethernet.edu.et/bitstream/123456789/1717/1/36%2c2012.pdf.pdf