Comparative Morphometric Analysis of the Hypoglossal Canal across Ethnic Groups: Data from Eastern Uttar Pradesh and Global Literature

Introduction:The hypoglossal canal (HC) is a key skull base conduit transmitting the hypoglossal nerve and associated neurovascular structures, with a morphology that varies considerably across populations and has important implications for craniovertebral junction surgery.This osteological study aimed to characterize HC morphometry and morphological variants in an Eastern Uttar Pradesh population and to compare these findings with international data.Materials and methods: Twenty adult dry skulls of regional origin were examined using a digital Vernier caliper to record maximum transverse and vertical diameters of the intracranial HC opening, and the distance from the HC to the basion, bilaterally.Canal shape was classified as round, oval horizontal, or oval vertical, and anatomical variants such as accessory canals and septation were documented.Results: Mean transverse and vertical diameters, and HC-basion distances demonstrated no statistically significant right-left differences, indicating bilateral symmetry, although individual asymmetry was present.Overall dimensions were smaller than values reported in Turkish, Italian, Egyptian, and some Indian series, supporting population-specific baseline metrics.Oval horizontal canals predominated on both sides, and accessory HCs were observed in a minority of skulls.Conclusion: These findings provide region-specific morphometric benchmarks and highlight the variability and potential surgical risk associated with HC anatomy.Accurate knowledge of HC dimensions, shape distribution, and variant patterns in this population can inform safer planning of transcondylar and related skull base approaches and enrich comparative cranial anthropology.