A Quantitative Analysis of Sex-Related Differences of the Lower Facial Third
In brief
Male lower face is about 11 mm wider and jaw angles 5° sharper than female
In a CT study of 50 adults, men's tragus-to-tragus width averaged 159.5 mm versus 148.2 mm in women, and their gonial and genial angles were roughly five degrees more acute. These objective differences can guide three-dimensional planning for facial gender-affirming surgery, though individual variation still requires personalized assessment.
- Journal
- Journal of oral and maxillofacial surgery : official journal of the American Association of Oral and Maxillofacial Surgeons (Q1)
- Published
- 22 August 2026
- Study design
- Cross-sectional study
- Evidence level
- Level 3, Low (CEBM 3b)
- Authors
- Elaine Lin, Habib Khoury, Sarah M Russel, Richard Wetherill, Shivani Desai, Elda L Fisher, et al.
- PMID
- 42697534
- DOI
- 10.1016/j.joms.2026.08.010
Why clinicians should know about it
- Picked for Anatomy (paper of the day, 7 September 2026): Sex‑related facial morphometry, quantitative CT cephalometry
Abstract
BACKGROUND: Understanding sexual dimorphism of the lower facial third is critical to planning facial gender confirmation surgery (FGCS). PURPOSE: The purpose of this study was to evaluate differences in the angles and proportions of the lower facial third between sexes and to provide objective measurements of these anatomical relationships. STUDY DESIGN, SETTING, SAMPLE: A retrospective cross-sectional study was conducted at a tertiary academic site. Computed tomography (CT) scans from adult patients with anatomically normal maxillofacial structures were included. Patients with a history of craniofacial pathology, facial fractures, or prior FGCS were excluded. PREDICTOR VARIABLE: Sex, coded as male or female. MAIN OUTCOME VARIABLES: The primary outcome variables of three-dimensional cephalometric measures including linear distances (tragus-tragus, gonial-gonial, and genial width), the ratio of genial to mandibular width, and angular measurements (genial, gonial, and geniolabial angles). To manage multiple comparisons, the Benjamini-Hochberg procedure was applied to control the false discovery rate at 5%. COVARIATES: Covariates included age, race, and body mass index. ANALYSES: Analytic statistics were calculated to assess sex differences utilizing the Wilcoxon rank-sum test. A multivariable linear regression evaluated the independent effect of sex while adjusting for covariates. Statistical significance was set at P value < .05. RESULTS: The sample was composed of 50 patients with average the age of 50.2 (SD = 16.3) years, and 25 (50%) were male. Males had statistically significantly wider faces than females as measured by tragus to tragus (males = 159.5 (8.0) mm; females = 148.2 (6.2) mm; P < .001) and gonial angle to angle (males = 97.2 (6.1) mm; females = 89.5 (6.2) mm; P < .001). The gonial (males = 125.0° (7.0°); females = 129.8° (5.6°); P = .01) and genial angle (males = 136.8° (7.3°); females = 148.0° (6.0°); P < .001) were more acute in males. CONCLUSIONS AND RELEVANCE: Males exhibit statistically significantly wider jaws and more acute mandibular angles than females. These objective measurements of lower facial third sexual dimorphism can inform three-dimensional virtual surgical planning to improve patient outcomes and satisfaction.
Abstract as published, via PubMed.
For healthcare professionals. The summary is generated by AI from the published abstract, and the evidence level is assigned automatically from the study design on the Oxford CEBM hierarchy. Neither is medical advice. Read the full paper before changing practice.