Int J Anat Res 2018, 6(2.1):5163-66. ISSN 2321-4287 5163 Original Research Article THE FORAMEN MAGNUM: A MORPHOMETRIC STUDY ON CT IMAGES OF ADULTS Supriya Garapati 1 , Ch. Santhi 2 , Pentyala Suneetha 3 , Krishna Sahith Reddy.K.V 4 . ABSTRACT Address for Correspondence: Mrs. Ch. Santhi, Assistant professor, Department of Anatomy, Narayana Medical College, Nellore, AndraPradhesh, India. E-Mail: kota.santhireddy@gmail.com Objective: The purpose of the present study was to assess the morphometric values of foramen magnum to evaluate sexual dimorphism as well as its clinical importance. Materials and Methods: The study was conducted on 100 (Male 56, Female 44) CT scans. Morphometric study was conducted on foramen magnum of occipital bone. From all the CT images the foramen magnum anteroposterior diameter and transverse diameter were measured. Area of foramen magnum was calculated automatically. Foramen magnum index was calculated by using the formula Ht/Br×100. The data was statistically analysed. Results: The mean anteroposterior diameter in males and females was 33.9± 2.78, 32.2 ± 2.24, the mean transverse diameter in males and females was 27.7±2.27, 26.7± 2.68 and the area of foramen magnum in males and females was 739.5 ±9.96 , 676.1 ± 8.76, index of the foramen magnum in males and females was 82.09±7.86, 83.02±9.55respectively Conclusion: This study concludes that the parameters measured were higher in males compared to females except foramen magnum index. This was noticed higher in females than males. KEY WORDS: Foramen magnum, Computed tomographic images, Morphometry. INTRODUCTION International Journal of Anatomy and Research, Int J Anat Res 2018, Vol 6(2.1):5163-66. ISSN 2321-4287 DOI: https://dx.doi.org/10.16965/ijar.2018.144 Access this Article online Quick Response code International Journal of Anatomy and Research ISSN (E) 2321-4287 | ISSN (P) 2321-8967 https://www.ijmhr.org/ijar.htm DOI-Prefix: https://dx.doi.org/10.16965/ijar DOI: 10.16965/ijar.2018.144 1 Professor and HOD, Department of Anatomy, ESIC Medical College, Sanath nagar, Hyderabad, Telangana, India. *2 Assistant professor, Department of Anatomy, Narayana Medical College, Nellore, AndraPradhesh, India. 3 Professor, Department of Radiology, Narayana Medical College, Nellore, AndraPradhesh, India. 4 Assistant professor, Department of Radiology, Narayana Medical College, Nellore, AndraPradhesh, India. Received: 13 Feb 2018 Peer Review: 13 Feb 2018 Revised: None Accepted: 07 Mar 2018 Published (O): 05 Apr 2018 Published (P): 05 Apr 2018 Journal Information ICV for 2016 90.30 Article Information area of the skull tends to withstand both physical insults and inhumation somewhat more successful than many other areas of the cranium [4].several studies conducted in foramen magnum of dry skulls to known the sexual dimorphism. In the present study we aimed at morphometric study of the foramen magnum in CT Scans. Foramen magnum is a three dimensional large aperture that lies within the basal region of the occipital bone of the skull [1, 2]. In any medi- colegal investigation, estimation of the sex of the skeletal remains is an essential element [3]. Due to the thickness of the cranial base and its relatively protected anatomical position, this