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?
Answer: Facial muscles contract and relax which give us the ability to produce facial expressions. These are governed by electrical impulses that travel through nerves which causes muscle stimulation. Damage in these nerves result inhibition of movement or paralysis among the muscles they control. By observing patient AM’s current appearance and actions, the drooping eye and mouth on the left side of his face as well as loss of the nasolabial fold suggests that he is experiencing facial paralysis. As his blood pressure is normal and he has no comorbidites, it can be inferred that the cause of the facial paralysis is nerve damage leading to being diagnosed of Bell’s palsy. Due to infection in the ear or contraction of the herpes simplex virus, the patient’s facial (VII) nerve was damaged affecting five facial muscles it controls namely the frontal belly, orbicularis oculi, orbicularis oris, buccinator, and platysma. Listed below are their respective functions:
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Frontal belly: draws scalp anteriorly, raises eyebrows, and wrinkles skin of forehead horizontally
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Orbicularis oculi: closes eye
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Orbicularis oris: closes and protrudes lips, compresses lips against teeth, and shapes lips during speech
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Buccinator: presses cheeks against teeth and lips, draws corner of mouth laterally, and assists in chewing
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Platysma: draws outer part of lower lip inferiorly and posteriorly and depresses mandible.
Aside from the mentioned symptoms observed from the patient, he could also experience the following issues:
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Aching of the ear or mastoid
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Decreased or excessive tearing
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Decreased tolerance to sound
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Taste disturbances
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Blurred vision