5 muscles and its actions.
- Frontalis. Elevates eyebrows & draws scalp forward and wrinkles skin of forehead.
- Orbicularis oculi. Closes the eyes.
- Orbicularis oris. Puckers the lips, compresses them against teeth, shapes the lips during speech, and closes the mouth.
- 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).
- Platysma. Draws the corners of the mouth, particularly lower lip, inferiorly and posteriorly as in pouting; depresses the lower jaw.
Describe the mechanism of his muscle weakness.
- Facial paralysis
- Unilateral paralysis of the muscles of facial expression
- Damage or disease of the facial (VII) nerve
- Inflammation on facial nerves
- Stroke on one side of the face
Other symptoms.
- Unable to wrinkle the forehead
- Unable to close the eye
- Unable to pucker the lips on the affected side
- Drooling
- Difficulty in swallowing
References
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Facn, D. C. T. D. M. (n.d.). Bell Palsy: Practice Essentials, background, anatomy. https://emedicine.medscape.com/article/1146903-overview#:~:text=The%20facial%20nerve%20passes%20through,%2C%20buccinator%2C%20and%20platysma%20muscles.
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Shennan, J. (2021). Muscles of Facial Expression | Anatomy | Geeky Medics. Geeky Medics. https://geekymedics.com/muscles-of-facial-expression/#:~:text=The%20muscles%20of%20facial%20expression,%3A%20orbital%2C%20nasal%20and%20oral.&text=These%20striated%20muscles%20broadly%20originate,and%20insert%20onto%20facial%20skin.
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Tortora, G., & Derrickson B. (2017). Principles of Anatomy and Physiology (15th ed.). Wiley.