Cephalometric Assessment of Airway-Related Hyoid Position and Velar Morphology Across Skeletal Malocclusions: A Cross-Sectional Study

Background: The anatomical position of the hyoid bone and the morphological characteristics of the soft palate play a key role in upper airway patency, craniofacial balance, and the coordination of functional structures. These features may vary depending on skeletal pattern and gender. This study aimed to evaluate the relationship between hyoid bone position, soft palate morphology, skeletal classification, and gender using lateral cephalograms. Methods: A total of 120 individuals (60 females and 60 males) were classified as Skeletal Class I, II, or III based on the ANB (A Point–Nasion–B Point) angle. Measurements reflecting hyoid position and pharyngeal airway width were analyzed, including C3–H (distance from the third cervical vertebra to the hyoid bone), C3–RGn (distance from the third cervical vertebra to retrognathion), H–RGn (distance from the hyoid bone to retrognathion), PNS–UPW (distance from the posterior nasal spine to the upper pharyngeal wall), and U–MPW (distance from the uvula to the middle pharyngeal wall). Soft palate types were classified according to the You classification. Statistical analyses included ANOVA (analysis of variance), the Kruskal–Wallis test, the independent samples t-test, the Mann–Whitney U test, and the chi-square test. Results: Significant differences in C3–RGn, H–RGn, and U–MPW were observed between Skeletal Classes I–III and Classes II–III (p < 0.05). In contrast, C3–H and PNS–UPW did not differ significantly among skeletal classes. Soft palate types showed no significant association with skeletal classification or gender. Gender-based comparisons revealed significant differences in C3–H, C3–RGn, H–RGn, and PNS–UPW (p < 0.05). Conclusions: Mandibular-related hyoid measurements and the U–MPW parameter were associated with skeletal pattern, whereas C3–H and PNS–UPW remained relatively stable. Soft palate morphology was not significantly influenced by skeletal class or gender. These findings suggest that the hyoid–tongue–soft palate complex should be evaluated in conjunction with mandibular position during orthodontic diagnosis and treatment planning.