Research Article Understanding the Lingual Frenulum: Histological Structure, Tissue Composition, and Implications for Tongue Tie Surgery Nikki Mills , 1,2 Donna T. Geddes, 3 Satya Amirapu, 2 and S. Ali Mirjalili 2 1 Pediatric Otolaryngology Department, Starship Children’s Hospital, Auckland, New Zealand 2 Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand 3 School of Medicine and Pharmacology, University of Western Australia, Crawley, Perth, Western Australia, Australia Correspondence should be addressed to Nikki Mills; nikki@webrage.co.nz Received 12 December 2019; Revised 16 April 2020; Accepted 11 May 2020; Published 21 July 2020 Academic Editor: David W. Eisele Copyright © 2020 Nikki Mills et al. is is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Lingual frenotomy has become an increasingly common surgical procedure, performed for a broad range of indications from birth through adulthood. is study utilizes histology to define the structure and tissue composition of the lingual frenulum and floor of mouth (FOM) fascia. En bloc specimens of anterior tongue, lingual frenulum, and FOM tissues were harvested from ten embalmed adult cadavers. An additional three fresh tissue cadaveric specimens were frozen with the tongue supported in an elevated position, to enable harvesting and paraffin embedding of the elevated lingual frenulum as a discrete specimen. All 13 specimens were prepared as ten-micron coronal sections using stains to determine the general morphology of the lingual frenulum, its relationship to neighbouring structures (Mason’s Trichrome), presence of elastin fibers (Verhoeff-van Gieson), and collagen typing (Picrosirius Red). Our results have shown a submucosal layer of fascia spanning horizontally across the FOM was present in all specimens, with variability in fascial thickness and histologic composition. is FOM fascia suspends the sublingual glands, vessels, and genioglossus from its deep surface. e elevated lingual frenulum is formed by a central fold of this FOM fascia together with the overlying oral mucosa with variability in fascial thickness and composition. With tongue elevation, the fascia mobilizes to a variable extent into the fold forming the frenulum, providing a structural explanation for the individual variability in lingual frenulum morphology seen in clinical practice. 1. Introduction e lingual frenulum is of significant clinical relevance because of its potential to restrict tongue mobility. e frenulum has traditionally been described as a mucosal fold, which can restrict tongue mobility by tethering to the mandible or floor of mouth (FOM) [1]. Over the last decade, there has been increasing popularity in the frenulum being conceptualized as a discrete submucosal connective tissue midline band or “string” [2]. However, the understanding of lingual frenulum structure has been comprehensively re- vised following two studies using microdissection of fresh tissue cadavers [3, 4] showing that the lingual frenulum is formed by a midsagittal fold in a layer of fascia that spans across the floor of mouth. Only two published articles on the histology of the human lingual frenulum exist but neither provide a com- prehensive understanding of frenulum morphology or structure [5, 6]. In 1966, Fuchs reported on histological analysis of 25 lingual frenulums harvested from cadavers aged 1 to 70 years old [5]. Nonkeratinized squamous epi- thelium was described covering the lingual frenulum, in direct continuation with the epithelium from both sides of the FOM as well as that of the ventral surface of the tongue. Connective tissue fibers beneath the epithelium in the region of the lingual frenulum were described as crossing diago- nally to the longitudinal axis of the frenulum, forming a scaffold-like framework. Despite these findings, Fuchs de- scribed the frenulum structure as a “band.” is discrepancy in interpretation was possibly due to their study assessing Hindawi International Journal of Otolaryngology Volume 2020, Article ID 1820978, 12 pages https://doi.org/10.1155/2020/1820978