Background: Foramen magnum is a big hole in the base of the skull. Its appearance can be useful in gender determination. So far, no study has been conducted in Iran that evaluates the value of foramen magnum in sex determination and calculates the cut-off points. This study aimed to evaluating of diagnostic value of the foramen magnum and to calculate the cut-off points for sex determination.
Methods: In this cross sectional study 50 male and 50 female patients referring to the radiology department of Rasol Akram Hospital in Tehran were evaluated. The required information about the sagittal diameter, transverse diameter, and diameter of foramen magnum were assessed by brain CT scan. Chi-square and independent t test was used for the comparison of different shapes and diameters between the sexes. ROC curve was used to determine the optimal cut-off point for each indicator.
Results: The best cut-off point to distinguish males from females along the anterior-posterior foramen magnum was calculated as 36.45 mm, at the transverse diameter of 30.4 mm. The proper cut-off points for the area of the foramen magnum were 877.477 mm2 and 870.29 mm2, based on the Teixeria formula and Routal formula respectively. Overall, the accuracy of these indicators was calculated as 85%.
Conclusion: Based on the results of this study using CT scans images, the diameter of the foramen magnum and its area had a high accuracy in sex determination.
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