MORPHOMETRIC ANALYSIS OF FORAMEN MAGNUM

Background: Diameters of foramen magnum are important because vital structures passing through it and for sex determination of skulls. The dimensions of the foramen magnum are clinically important because vital structures passing through it may endure compression such as in cases of foramen magnum herniation, foramen magnum meningiomas and foramen magnum achondroplasia. The knowledge of foramen magnum diameters is needed to determine some malformations such as Arnold Chiari syndrome, which shows expansion of transverse diameter. Objectives: To study longitudinal diameter, transverse diameter and area of foramen magnum in relation to sex. Methods: 150 dry skulls and 30 CT scan images of living subjects were studied. Diameters of foramen magnum were measured by vernier calipers and its area was calculated by formula. Diameters and area of foramen were measured automatically. Results: The mean longitudinal diameter of foramen magnum in male was 33.4mm and female was 33.1mm and by CT Imaging method in male was 38.5mm and female was 35.2mm. The mean transverse diameter of foramen magnum in male was 28.5mm and female was 27.3mm and by CT Imaging method in male was 29.1mm and female was 27.6mm. Conclusion: longitudinal and transverse diameters and area of foramen magnum of male skulls were greater than females.