Morphometric evaluation of foramen magnum

Vidya H K¹, Nagashree M V^2*

Abstract               Background and Aim: Foramen magnum is an important landmark in the posterior part of the skull base, vital structures pass through it. Those structures may suffer compression in cases of foramen magnum achondroplasia and foramen magnum brain herniation. The knowledge of foramen magnum diameters are needed to determine some malformaitons sucha as Arnold chiari syndrome, which shows expansion of transverse diameter. The purpose of this study was to evaluate the measurements of foramen magnum and to calculate area and index of foramen magnum. Materials and Methods: The present study was carried out on 134 dry skull bones, the diameters of foramen magnum were measured using digital vernier calipers and its Area and Index were calculated. Results: The mean anteroposterior diameter of foramen magnum was 34.56mm in males and 32.7mm in females. The mean transverse diameter of foramen magnum was 28.95mm in males and 27.57mm in females. The mean foramen magnum index was 84.07 and mean area of foramen magnum was 762.01mm². Conclusion: Results of the present study may be useful for neurosurgeons in analyzing morphological anatomy of craniovertebral junction for transcondylar approach in brainstem lesions. Since mean anteroposterior diameter, transverse diameter and area of foramen magnum were more in males compared to females hence it may be use full in sex determination of human skull in forensic analysis and anthropology studies.

Key Words: Foramen magnum, morphmetric evaluation, skull base, sex determianiton.