Sex and age effects on caudate nucleus size: implications for neurosurgery and neurodegenerative biomarkers

Introduction : The caudate nucleus (CN) plays a central role in motor control, cognition, and emotional regulation. Structural alterations of the CN have been associated with various neurodegenerative and psychiatric disorders. While volumetric magnetic resonance imaging (MRI) remains the standard for assessing CN morphology, linear morphometry offers a simpler and more accessible alternative that does not require advanced post-processing. Normative data on age- and sex-related variations in CN linear dimensions remain limited. Aim : This study aimed to establish reference values for CN linear measurements and evaluate their associations with age and sex in healthy adults. Methods : A total of 241 neurologically healthy adults (134 females, 107 males; aged 30–70 years) underwent 1.5-T MRI. Individuals with structural brain abnormalities, prior neurosurgery, or systemic disease were excluded. Data distribution was assessed using the Shapiro–Wilk test. Sex differences were analyzed using the Mann–Whitney U test, and age correlations were evaluated using Spearman’s rank correlation coefficient (ρ). Results : Males demonstrated significantly greater right CN width compared with females (U=2756.0, p =0.045, r =0.15). Age showed a weak but significant negative correlation with left CN length (ρ=−0.18, p =0.015). No additional significant sex- or age-related differences were observed. Conclusion : This study establishes normative CN linear morphometric values and demonstrates subtle sex- and age-related variations. Linear CN measurements may support personalized neurosurgical planning and aid in the development of structural biomarkers. Longitudinal and multimodal studies are warranted to validate their predictive value.