A Morphometric Analysis of the Foramen Magnum in Human Dry Skulls from South India and Its Clinical Relevance

Abstract

Introduction: At the craniovertebral junction, the foramen magnum-a very important structure, has variations related to its shape and size, which are of immense neurosurgical, radiological and forensic importance. The morphometry of the foramen magnum has virtually less study for the South Indian population.To assess the morphometric parameters and shape variations in the foramen magnum of adult dry skulls of South Indian origin.
Materials and Methods: A cross-sectional descriptive study was undertaken using 54 adult human dry skulls of undetermined sex from four medical colleges in Andhra Pradesh. Measurements for anteroposterior diameter (APD), transverse diameter (TD), foramen magnum area (FMA), and foramen magnum index (FMI) were taken. Digital Vernier callipers were used for taking the measurements. The shape was classified according to the standard morphological criteria. Statistical analysis was performed, with the use of SPSS version 26 for Pearson correlation.
Results: The most common shape was oval (62.97%), followed by pear (20.37%), round (11.11%), hexagonal (3.70%), and irregular (1.85%). Mean values were APD-34.76 ± 2.49 mm; TD-26.93 ± 2.10 mm; FMA-734.82 ± 112.17 mm²; and FMI-77.48 ± 4.82. Correlation between APD and FMA was strong, reporting r=0.719, p <0.001, while correlation between TD and FMA was moderate, with r=0.520, p=0.008.
Conclusion: The morphometric and shape variations of the foramen magnum in South Indian skulls as described in this study are of great clinical importance to neurosurgical practice and forensic identification in craniovertebral pathologies interpretation.