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?
AFFECTED MUSCLES
- Occipitofrontalis (Frontal Belly)
- Action: Draws scalp anteriorly, raises eyebrows, and wrinkles skin of forehead horizontally as in look of surprise
- Orbicularis oculi
- Action: Closes eye
- Orbicularis oris
- Action: Closes and protrudes lips as in kissing; compresses lips against teeth; and shapes lips during speech
- Buccinator
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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)
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- Platysma
- Action: Draws outer part of lower lip inferiorly and posteriorly as in pouting; depresses mandible
Bell’s palsy, also known as facial paralysis, is a unilateral paralysis of the muscles of facial expression. It is due to damage or disease of the facial (VII) nerve. Possible causes include inflammation of the facial nerve due to an ear infection, ear surgery that damages the facial nerve, or infection by the herpes simplex virus. The nerve can also be damaged by trauma, tumors, and stroke. The paralysis causes the entire side of the face to droop in severe cases.
The person cannot wrinkle the forehead, close the eye (even while sleeping), or pucker the lips on the affected side. Drooling, swallowing difficultues, and loss of taste can also occur. Eighty percent of patients recover completely within a few weeks to a few months. Others are permanently paralyzed. Bell's palsy symptoms are similar to those of a stroke.