Secular Changes in Craniofacial Morphology Over the Last 2000 Years in Milan, Italy

This study aims to analyze secular changes in craniofacial morphology over 2000 years in Milan, examining variations in cra- nial dimensions across historical periods and between sexes. It utilizes standard anthropometric techniques to provide insights into the evolution of craniofacial morphology within this urban population. The study includes 213 crania from five historical periods, with 29 craniofacial measurements selected based on established bioarchaeological practices. These measurements are commonly used in bioarchaeological and forensic anthropological research, as outlined in standard data collection procedure manuals. Statistical analyses, including ANOVA, z-­ scores, and post hoc comparisons, were performed to identify significant temporal changes and sex-­ specific differences in cranial dimensions. Significant secular changes were detected in eight cranio- facial measurements: Maxillo-­ Alveolar Breadth, Foramen Magnum Breadth and Length, Biasterionic Breadth, Orbital Breadth, Parietal Chord, Cranial Base Length, and Bimaxillary Breadth. Variations between sexes were noted, with Biasterionic Breadth showing significant change in females, and Foramen Magnum Breadth, Orbital Breadth, and Bimaxillary Breadth in males. Post hoc analyses highlighted shifts in cranial dimensions from the Roman to the Contemporary era, suggesting consistent trends towards broader foramen magnum and midface dimensions over time. This study is the first to comprehensively document craniofacial morphological changes across all major historical periods in Milan, revealing significant diachronic trends likely driven by environmental, cultural, and demographic factors. The findings underscore the dynamic nature of cranial morphology as it adapts to changing lifestyles and conditions, reflecting Milan's complex history of biological and cultural transformations. Further research is needed to corroborate these trends and explore their underlying causes.