Sexual Dimorphism and Age-Related Structural Changes in the Human Larynx: A Morphometric Study with Histological Correlates Relevant to Voice and Diagnostic Assessment.

Background/

Objectives

The human larynx exhibits marked sexual dimorphism and undergoes age-related structural remodeling, both of which influence voice characteristics and have important implications for diagnostic assessment. While sex-related differences in laryngeal size are well recognized, the extent to which aging contributes to dimensional versus qualitative structural changes remains incompletely defined. This study aimed to analyze sex- and age-related morphometric and histological characteristics of the human larynx, with a focus on features relevant to voice evaluation and diagnostic interpretation.

Methods

A cross-sectional anatomical study was conducted on 80 cadaveric human larynges preserved in 10% buffered formalin. Specimens were stratified by sex and age (<30, 30-60, and ≥60 years). Direct morphometric measurements included anteroposterior laryngeal length, thyroid cartilage height, thyroid angle, and relative glottic area. Epiglottic morphology and the presence of laryngeal cartilage calcification/ossification (binary classification: present vs. absent) were recorded. Histological analysis of vocal fold tissue was performed on a stratified subset of specimens. Statistical analysis included t-tests, chi-square tests, two-way ANOVA, effect size estimation, and logistic regression.

Results

Male specimens showed significantly greater anteroposterior length, thyroid cartilage height, and relative glottic area, along with a narrower thyroid angle, compared with females (all p < 0.001), with large effect sizes. Age did not significantly influence overall laryngeal dimensions. In contrast, cartilage calcification/ossification increased markedly after the age of 60. Logistic regression identified age ≥ 60 years as the only independent predictor of calcification (OR = 4.37, p = 0.039), while sex was not significant. Epiglottic morphology demonstrated a sex-dependent distribution. Histology revealed age-related muscle atrophy and reduced collagen and elastin density.

Conclusions

Sex defines the baseline morphometric framework of the adult larynx, whereas aging, particularly beyond 60 years, drives qualitative structural degeneration. These findings provide a reproducible anatomical reference for distinguishing sex-related variation from age-related changes in diagnostic assessment.