Quantitative Analysis of Sexual Dimorphism in Three-Dimensional Facial Anthropometry in Contemporary Thai Population:...

Facial feminization surgery (FFS) reshapes masculine facial attributes to align with feminine norms, yet normative anthropometric data for Asian populations remain sparse. We therefore quantified sex-related 3-dimensional (3D) facial metrics in healthy Asian adults to delineate dimorphic benchmarks for surgical planning. We prospectively recruited 40 healthy Asian adults (20 males, 20 females; age 18 to 45 years, mean 28.6 years; body mass index 21.8 kg/m 2 ) and obtained 3D images with the Vectra XT 3D system. Linear and angular metrics for the upper, middle, and lower facial thirds were compared between sexes with independent-samples t  tests (α = 0.05). Male faces showed greater vertical dimension (196.7 mm versus 190.3 mm, P  = 0.023), broader zygomatic (127.9 mm versus 120.7 mm, P  < 0.001), and mandibular widths (124.4 mm versus 113.8 mm, P  < 0.001). They also had longer noses (43.7 mm versus 37.9 mm, P  < 0.001) with increased tip projection (23.9 mm versus 19.8 mm, P  < 0.001) and more acute glabellar (146.8° versus 150.9°, P  = 0.025) and nasofrontal (137.1°  versus 142.6°, P  = 0.011) angles. Female faces displayed increased forehead convexity (ratio 1.030 versus 1.011, P  < 0.001), steeper palpebral slant (9.4° versus 6.2°, P  < 0.001), and wider columella-labial angle (109.6° versus 104.6°, P  = 0.032). They also exhibited a more obtuse gonial angle (135.4° versus 129.6°, P  = 0.002) and shorter upper lip (23.9 mm vs. 26.0 mm, P  = 0.007). Age and body mass index did not differ between sexes. These quantitative benchmarks delineate sexual dimorphism in Asian visages and furnish evidence-based targets for FFS planning. Effective FFS should reduce bony and soft-tissue prominence, create obtuse angles, and incorporate targeted lifting to reproduce the feminine template, thereby enhancing gender-affirming outcomes.