Anat Cell Biol.  2021 Dec;54(4):522-524. 10.5115/acb.21.127.

Extended crossing fibers of the mentalis muscle attaching to the contralateral mandible

• Iwanaga J
• Hur MS
• Kikuta S
• Ibaragi S
• Tubbs RS

• KMID: 2523582
• DOI: http://doi.org/10.5115/acb.21.127

Abstract

Fibers of the facial muscles occasionally extend, cross the midline, and connect to surrounding structures on the contralateral side, perhaps enabling the mouth to make more delicate movements and generate more facial expressions. This case report describes a variant in which the extended fibers of the mentalis crossed the midline and indicates the relationship of these fibers to the surrounding structures. Some of the deepest fibers of the mentalis descended inferomedially and crossed transversely just below the chin prominence to attach to the periosteum of the mandible on the contralateral side. The variation presented in this study shed light on the interactions of the mentalis with the surrounding muscles.

Keyword

Mentalis; Facial muscles; Anatomy

Figure

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  Fig. 1 Extended crossing fibers of the mentalis muscle (MT) attaching to the mandible of the contralateral side at the posterior aspect. Some of the deepest fibers (black arrowheads) of the MT descended inferomedially and crossed transversely just below the chin prominence to attach to the periosteum of the mandible on the contralateral side below the corner of the mouth by the thin aponeurosis (white arrowhead). After crossing the chin, these fibers were continuously arranged below the incisivus labii inferioris (ILI) on the contralateral side. Some of the deepest fibers of the MT were reflected inferiorly to reveal the extended crossing fibers of the muscle. DLI, depressor labii inferioris.

Reference

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