Relations Between Foramen Magnum and Associated Structures Located Within the Skull Base of The Turkish Population

Aim: For reliable diagnosis and surgical approach, a fundamental knowledge of the normal anatomy and the morphometric measurements of the skull base are important to the clinicians. The aim of this study is to evaluate the morphometric dimensions of Foramen Magnum (FM) and clivus with respect to the related structures of Turkish population. Methods: 313 patients’ computed tomography angiography (CTA) image series of head and neck region was examined retrospectively. Length of the clivus (LoC), angle between the clivus and posterior margin of FM (C-FM), angle between the line along the posterior surface of the clivus and the other line along the posterior side of the dens of axis (C-D), antero-posterior diameter of the FM (FMap), largest transvers distance between lateral margins of the FM (FMt) and the area of the FM (FMa) were measured. Results: The mean values of LoC, C-FM, C-D, FMap, FMt and FMa in female group are 32.1 ± 3.4 mm, 153.46° ± 9.13, 140.61° ± 11.93, 34.72 ± 2.57 mm, 29.25 ± 2.1 mm and 733.26 ± 102.09 mm2 respectively. And also the mean values of LoC, C-FM, C-D, FMap, FMt and FMa in male group are 35.2 ± 4 mm, 149.93° ± 8.6, 141.28° ± 10.33, 36.29 ± 2.89 mm, 30.79 ± 2.27 mm and 800.12 ± 110.62 mm2 respectively. Conclusion: Parameters of the structures related to the skull base, especially the FM can easily be evaluated using CTA