MORPHOLOGY AND MORPHOMETRIC ANALYSIS OF FORAMEN MAGNUM IN ADULT HUMAN SKULLS

Abstract

Background: The Foramen magnum is an important landmark present at the base of the skull, it serves as a transitional zone between spine and skull. It is closely related to vital structures such as medulla oblongata, meninges, anterior and posterior spinal arteries, vertebral arteries and spinal accessory nerve, passing through it hence thorough knowledge of foramen magnum is required. These structures passing may undergo compression in case of foramen magnum herniation, meningiomas and foramen magnum achondroplasia. Aims: The present study aims in performing the morphometric analysis foramen magnum and to classify it based on its shape. Materials and methodology A total number of 64 adult dry human skulls were evaluated from the Department of Anatomy, ESIC MC & PGIMSR, Rajajinagar, Bengaluru, Karnataka. Results: The mean antero-posterior diameter was found to be 34.10 ± 2.63 mm, mean transverse diameter was 28.07 ± 1.87 mm, with mean area of 752.07 ± 111.97 mm2 and foramen magnum index was 1.21 ± 0.12. The foramen magnum shapes were classified as oval (30%), circle (12%), hexagonal (3%), pentagonal (5%), egg (17%), leaf (6%), irregular (27%). Conclusion: The morphometry along with other parameters can be used for sex determination in partially damaged skull bones of unknown individuals. The obtained data is useful not only for anatomists but also the neurosurgeons, otorhinolaryngologist and radiologists. Keywords: Foramen Magnum, Morphometry, Meningioma, Achondroplasia, Antero-Posterior Diameter, Transverse Diameter, Foramen Magnum Area, Foramen Magnum Index.