Frontal Sinus Dimensions and Forehead Prominence According to Sex and Skeletal Sagittal Patterns in Syrian Adults: A Cephalometric Study

Background This study aimed to evaluate frontal sinus dimensions and forehead prominence in relation to sex and skeletal sagittal patterns in Syrian adults using lateral cephalometric analysis. Methodology A retrospective cross-sectional study was conducted among 216 Syrian adults aged 18-30 years, equally distributed among skeletal Class I, Class II, and Class III groups with balanced sex distribution. Lateral cephalometric radiographs were analyzed to measure frontal sinus height (SH-SL), frontal sinus width (SAP-SPP), and forehead prominence (L1-L2). Statistical analysis included the Shapiro-Wilk test, two-way analysis of variance (ANOVA), Tukey’s honestly significant difference post hoc test, Pearson correlation analysis, and intraclass correlation coefficient assessment. Statistical significance was set at p-values <0.05. Results Two-way ANOVA demonstrated significant effects of sex on frontal sinus height, frontal sinus width, and forehead prominence (p < 0.001). Males exhibited significantly greater values for all evaluated variables than females. Skeletal sagittal classification showed a significant effect only on forehead prominence (p = 0.004), with skeletal Class II subjects demonstrating significantly lower values than skeletal Class I and Class III subjects. No significant differences in frontal sinus dimensions were observed among skeletal classes. Pearson correlation analysis revealed positive associations between frontal sinus dimensions and forehead prominence. No significant interaction was observed between sex and skeletal sagittal classification for any of the evaluated variables. Conclusions Frontal sinus dimensions in Syrian adults appear to be influenced predominantly by sex rather than skeletal sagittal classification, whereas forehead prominence varies according to both sex and skeletal sagittal pattern. Positive correlations between frontal sinus dimensions and forehead prominence suggest a partial association between these structures; however, forehead morphology is likely influenced by additional craniofacial factors. These findings highlight the importance of considering sexual dimorphism when evaluating frontal craniofacial morphology and suggest that forehead prominence may reflect certain sagittal craniofacial characteristics.