Morphometric variability of the foramen magnum in a historical skeletal series from Rome (17th-19th century): limited sexual dimorphism and age-related stability.

BACKGROUND: The foramen magnum (FM) is the largest opening at the cranial base and serves as a critical anatomical structure connecting the cranial cavity to the vertebral canal. Owing to its functional and clinical importance, the morphology and morphometry of the FM have been extensively examined in anatomical and anthropological research. The present study evaluates the morphometric variability of theFM in a historical European population, focusing on differences by sex and age. MATERIALS AND METHODS: The analysis included 101 adult human skulls from the historical osteological collection of the Museum of Anthropology "Giuseppe Sergi" at Sapienza University of Rome. The skulls date to the 17th-19th centuries. We measured the anteroposterior length and transverse width of the foramen magnum using a digital caliper. We also calculated theFM index and surface area. Shape was classified according to the morphological types described by Richards and Jabbour (2011). Statistical analyses were conducted to assess differences associated with sex and age. RESULTS: The mean FM length and width measured 34.98 mm and 29.63 mm, respectively. No statistically significant differences were identified between males and females for any of the analyzed parameters. Likewise, no significant differences were observed between younger and older individuals. Morphological analysis revealed variability in FM shape, with the two-semicircle type being the most frequently observed configuration in both sexes. CONCLUSIONS: The morphometric parameters of theFM in the ROMA skeletal series are consistent with ranges reported for other human populations. No significant sex- or age-related differences were found, indicating relative developmental stability of this structure. FM measurements may contribute to anthropological and forensic analyses. However, their utility for sex estimation is limited.