Morphological and Morphometric Variations in Foramen Transversarium: A Cross-sectional Study in Dried Cervical Vertebrae of Western Odisha Origin

Introduction: Foramen transversarium refers to bilateral foramina found lateral to the vertebral body in the transverse process cervical vertebrae. Many variations are observed in these foramina which may lead to vertebrobasilar insufficiency, labyrinthine hearing disturbances along with neurological symptoms compression or tortuosity of vertebral artery as it passes through the foramen. Aim: To study the morphological and morphometric variations of the foramen transversarium in cervical vertebrae. Materials and Methods: This cross-sectional study was conducted in Department of Anatomy, Veer Surendra Sai Institute of Medical Sciences and Research, Burla, Odisha, India, from June to August 2022. A total of 367 human cervical vertebrae procured from the anthropology section of Department of Anatomy. Vertebrae with any damage to foramen transversarium discarded. Each vertebra was observed for shape, size, symmetry, number of foramen transversarium and osteophytic encroachment. Distance of foramen transversarium from the medial margin uncinate process was measured bilaterally in C3 to C7 vertebrae. Data collected was tabulated and analysed by Microsoft software 2019. Results: Mean anteroposterior diameter and transverse diameter in left-side were 5.45 mm and 5.42 mm, respectively and in right side the measurements were 5.29 mm and 5.23 mm, respectively. Double foramen transversarium was observed in 40 (10.9%) vertebrae. Among them 18 (4.9%) were bilateral and 22 (6.0%) were unilateral. In 2 (0.54%) vertebrae there was triplication of foramen transversarium. In 34 vertebrae (9.26%) there was incomplete duplication of which 9 (2.45%) were bilateral and 25 (6.81%) were unilateral. Six different shapes of foramen transversarium were observed out of which round shape (62.1%) was the most common finding. In 261 (71.1%) of vertebrae the main foramen transversarium was symmetrical in both sides but in 106 (28.9%) it was asymmetrical. Osteophytic encroachment was found in 14 (3.81%) vertebrae. The mean distance of the foramen from medial margin of uncinate process was 5.32 mm on the left and 5.42 mm on the right-side. Conclusion: The morphological data like very narrow foramina and such a high number of accessory foramina produced through the present study definitely points towards the variations of vertebral vessels.