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Mentalis

Muscle that raises the central portion of the lower lip

Field	Value
Name	Mentalis
Latin	musculus mentalis
Image	Mentalis.png
Caption	Muscles of the head, face, and neck.
Origin	Anterior mandible
Insertion	Chin
Action	Elevates and wrinkles skin of chin, protrudes lower lip
Nerve	Mandibular branch of facial nerve

The mentalis muscle is a paired central muscle of the lower lip, situated at the tip of the chin. It originates from the mentum of the mandible, and inserts into the soft tissue of the chin. It is sometimes referred to as the "pouting muscle" (as in duck face) due to it raising the lower lip and causing chin wrinkles.

Structure

The mentalis muscle originates from the mental protuberance of the mandible near the midline. It inserts into the soft tissue and skin of the chin.

Function

The mentalis muscle causes a weak upward-inward movement of the soft tissue complex of the chin. This raises the central portion of the lower lip. In the setting of lip incompetence (the upper and lower lips not touching each other at rest), the contraction of the mentalis muscle can bring temporary but strained oral competence.

In conjunction with the orbicularis oris muscle (for the upper lip), the mentalis muscle allows the lips to "pout". Externally, contraction of the mentalis muscle causes wrinkling and dimpling of the skin on the chin, as used in expressions of doubt or displeasure.

Clinical significance

The mentalis muscle can be easily assessed using ultrasound.

Geniospasm

Main article: Geniospasm

Geniospasm is a genetic movement disorder of the mentalis muscle. It involves repetitive contraction of the muscle, with episodes lasting between seconds and hours. Certain medications may be used to treat it, such as haloperidol and benzodiazepines. Injection of botulinum toxin (to temporarily paralyse the muscle) may be more effective.

Cosmetics

The mentalis muscle may be partially paralysed using botulinum toxin to reduce wrinkling of the skin of the chin. This may be done for cosmetic purposes.

Additional images

File:Gray176.png|Outer surface of mandible. Mentalis is indicated by the red circle at left. File:Mentalis animation small.gif|Position of mentalis (red) File:Braus 1921 376.png|Action of the mentalis muscle

References

{{EMedicine. article. 835209. Lips and Perioral Region Anatomy
(2004-09-01). "Depressor labii inferioris resection: an effective treatment for marginal mandibular nerve paralysis". British Journal of Plastic Surgery.
Zide, Barry M.. (March 2000). "The Mentalis Muscle: An Essential Component of Chin and Lower Lip Position". [[Plastic and Reconstructive Surgery]].
Glaser, Dee Anna. (2009). "Botulinum toxin: therapeutic clinical practice and science". [[Saunders (imprint).
(2013). "Quantitative ultrasonography of facial muscles". Muscle & Nerve.
(2009). "Movement Disorders 4". [[Saunders (imprint).

Info: Wikipedia Source

This article was imported from Wikipedia and is available under the Creative Commons Attribution-ShareAlike 4.0 License. Content has been adapted to SurfDoc format. Original contributors can be found on the article history page.

muscles-of-the-head-and-neck

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