The mentalis muscle is now considered key structures when performing procedures for rejuvenating the lower face. The aim of this study was to determine the anatomical morphology and location of the mentalis muscle and thereby provide anatomical information for facilitating clinical procedures designed to rejuvenate the lower face. Forty-four adult hemifaces from five Thai cadavers and 21 Korean cadavers were dissected to identify the locations of the mentalis muscle. Sixty-six hemifaces from 33 healthy young Korean subjects were included in an ultrasonographic study. The depth of the mentalis muscle below the skin surface, the thickness of the mentalis muscle, and the distance from the bone to the mentalis muscle were measured at the two points that were 5 mm lateral to the most-prominent point of the chin. The mentalis muscle was classified into two types based to its shape: in type A (86.4%, 38 of the 44 cases) it was dome shaped in three dimensions, while in type B (13.6%, 6 of the 44 cases) it was flat. The mentalis muscle was present mostly at the area 5–10 mm from the midsagittal line and 20–30 mm from a horizontal line connecting the mouth corners. The mentalis muscle was present between depths of 6.7 to 10.7 mm below the skin. This new information about the location of the mentalis muscle may help when identifying the most effective and safe botulinum toxin injection points and depths during esthetic procedures for weakened facial rhytides on the lower face.
Bibliographical noteFunding Information:
Funding: This research was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (No. 2018R1A5A7023490).
Author Contributions: Conceptualization, D.-Y.C. and H.B.; methodology, D.-Y.C. and H.B.; validation, H.-J.K. and K.-S.H.; formal analysis, D.-Y.C., J.-H.B. and H.B.; data curation, D.-Y.C., J.-H.B. and H.B.; writing—original draft preparation, D.-Y.C. and H.B.; writing—review and editing,H.B.; visualization, D.-Y.C., J.-H.B. and H.B.; supervision, H.-J.K. and K.-S.H.; project administration, K.-S.H.; funding acquisition, K.-S.H. All authors have read and agreed to the published version of the manutoscript. the thickness of the submentalis fat) were measured using the ImageJ program (National Institutes of Health, Bethesda, MD, USA) (Figure 7B). All of the study procedures were Funding:Thisresearch was supported bythe NationalResearch Foundation ofKorea(NRF) grant No. 2-2017-0023), and they were fully explained to all volunteers, who then provided written consents. Institutional Review Board Statement: The studywas conducted according to the guidelines ofthe DeclarationofHelsinki,andapproved bytheInstitutionalReviewBoardofYonseiUniversityDen-tal Hospital (IRB No. 2-2017-0023).
© 2021 by the authors. Licensee MDPI, Basel, Switzerland.
All Science Journal Classification (ASJC) codes
- Health, Toxicology and Mutagenesis