Re-writing the laryngeal anatomy

The larynx is a small but highly specialized structure, exhibiting notable sex-related variations. Previous morphometric studies often focused on isolated features, such as the thyroid angle, limiting understanding of overall laryngeal anatomy.

We retrospectively analyzed 157 high-resolution neck computed tomography (CT) scans (67 males, 90 females; age range: 21-89 years) obtained for indications unrelated to laryngeal pathology. Morphometric measurements included laryngeal length, dimensions of the thyroid, cricoid, and arytenoid cartilages, glottic length, total and free-part lengths of the epiglottis, epiglottic thickness and angle, and pre-epiglottic space volume. Statistical analyses employed Mann-Whitney U tests to evaluate sex- and age-related differences and assess predictive relationships between parameters.

Significant sex-related differences were observed across most laryngeal parameters, with the largest differences in epiglottic length, laryngeal length, thyroid angle, and thyroid lamina height (p < 0.00001). Epiglottic length showed the strongest association with sex and was the strongest predictor of total laryngeal length (R² = 0.74, p < 0.0001). The free part of the epiglottis also differed significantly between sexes, whereas epiglottic thickness showed only weak sex association. Age effects were minimal; epiglottic angle slightly decreased with age (p = 0.027), while pre-epiglottic space volume was influenced by both sex and age (p < 0.01).

This study provides comprehensive in vivo data on laryngeal dimensions, establishing reference values and clarifying their relationships with sex, age, and other anatomical parameters. The findings highlight sexual dimorphism in laryngeal morphology and offer a valuable resource for clinical and anatomical studies.