A morphometric and comparative study of foramen magnum in North Indian population

Introduction: Cranial base, especially the foramen magnum (FM), is of particular interest for anatomists, anthropologists, and neurosurgeons due to its complex relations with vital structures in this region. It is important as well as mandatory to have knowledge about its normal and variant dimensions for better transcondylar surgical approach. Materials and methods: Various diameters of foramen magnum of 120 adult North Indian dry skulls of unknown age and gender were examined using an electronic digital sliding caliper. Results: The commonest FM shape was oval and rarest was irregular. The mean anteroposterior (AP) and transverse diameters were 34.68 +/- 2.88 mm and 27.24 +/- 2.4 mm, respectively. The mean surface area was 757.09 +/- 115.82 mm(2). The mean Foramen Magnum Index (FMI) was 78.71 +/- 5.94. Discussion: Results provide a baseline data for anatomists and important information for neurosurgeons to approach the cranial base with maximum safety and minimum mortality and morbidity. (C) 2015 Anatomical Society of India. Published by Elsevier, a division of Reed Elsevier India, Pvt. Ltd. All rights reserved.