Morphometric Study of Foramen Transversarium in Dried Cervical Vertebrae: A Cross-sectional Osteological Study in Eastern Indian Population

Introduction: The Foramen Transversarium (FT), located in the transverse process of cervical vertebrae, is a key feature for the identification of cervical vertebrae. These foramina vary in size, shape and number, and they may even be absent. Accessory Foramen Transversarium (AFT) may be present due to developmental failure, along with variations in the course of the vertebral artery, which may predispose individuals to neurological symptoms. Aim: To examine the morphometry of FT and the occurrence of AFT in dried cervical vertebrae. Materials and Methods: A cross-sectional osteological study was conducted in the Department of Anatomy, Kalinga Institute of Medical Sciences (KIMS), Odisha, India, from January 2013 to August 2014. Five hundred dried human cervical vertebrae from C1 to C7 were studied for the morphometry of FT, considering parameters such as shape, Anteroposterior Diameter (APD), Transverse Diameter (TD) and the presence of accessory foramina. According to their shape, the foramina in the present study were classified into five types (type 1 to type 5) All measurements were taken using vernier callipers. The analysis was conducted using Statistical Package for Social Sciences (SPSS) software version 20.0. Results: In the present study, type 3, which is the transversely elliptical FT, was the most common type, with 452 out of 1,000 (45.2%), followed by type 4, with 168 out of 1,000 (16.8%). The maximum APD of FT was found in the C1 vertebra, with mean values of 5.86±0.93 mm on the left and 5.83±0.92 mm on the right-side. The maximum TD was found in typical cervical vertebrae, with mean values of 5.37±0.91 mm on the left and 5.35±0.91 mm on the right-side. The incidence of accessory foramina was highest in the C6 vertebrae, with 21 out of 58 (36.2%), and lowest in the C2 vertebra (0%). Conclusion: The present morphometric study shows a predominance of the transversely elliptical shape of FT. The maximum APD was observed in the C1 vertebra, while the maximum TD was noted in typical cervical vertebrae. The observations regarding the Eastern Indian population may be helpful for neurosurgeons to achieve better surgical outcomes.