Hyoid Bone Position in Subjects with Different Vertical Jaw Discrepancies

Abstract

Background: The hyoid bone plays a critical role in craniofacial dynamics, influencing respiration, swallowing, and mandibular posture. Its position varies with vertical skeletal morphology, yet region-specific cephalometric norms for South Asian adults remain limited. Objective: To evaluate hyoid bone position among adults with different vertical skeletal divergence patterns and assess the influence of gender on linear and angular cephalometric parameters. Methods: This cross-sectional study analyzed 159 adult lateral cephalograms (18–30 years) obtained at Bolan Medical Complex, Quetta. Participants were classified into hyperdivergent, normodivergent, and hypodivergent groups based on Frankfort Mandibular Plane Angle (FMA) and GoGn/SN values. Hyoid position was assessed using linear (Hy–Rgn, Hy–C3, C3–Rgn, Hy–PTV, Hy–PNS, Hy–S) and angular (C3/Hy/S, Hy/C3/S) variables. Nonparametric tests compared differences across groups and between genders, with p < 0.05 as significant. Results: Significant intergroup differences were observed for all hyoid measurements (p < 0.001). Hyperdivergent individuals exhibited a superior–anterior hyoid position, whereas hypodivergent subjects showed an inferior–posterior position. Males demonstrated consistently greater linear and angular values than females (p < 0.05), independent of skeletal divergence pattern. Conclusion: Hyoid bone position varies systematically with vertical skeletal pattern and gender. These findings highlight the diagnostic importance of including hyoid cephalometrics in orthodontic assessments and emphasize the need for gender- and population-specific reference standards in South Asian adults.