Anatomical variations of the foramen transversarium in cervical vertebrae: findings, review of the literature, and clinical significance during cervical spine surgery
AIM Foramina transversaria (FT) are located on the transverse processes of cervical vertebrae. These foramina are known to exhibit variations with regard to size, shape and may even be absent or duplicated. The aims of this study are to investigate the shape, size and variations of FT in an ancient population and to point out the importance of double FT in the human anatomy. MATERIAL and METHODS 262 ancient skeletons, dated 6th c AD, were unearthed from the Iasos Archaeological site between 1979 and 1987. Of these skeletons, 22 cervical vertebrae belonging to 21 individual skeletons were examined for the variations of FT. RESULTS Fifteen (68.2%) of the skeletons were male and 6 were female. All of the FT were round in shape. Among the 22 cervical vertebrae, double FT was found in 5 (22.7%) vertebrae, while unilateral in 3 and bilateral in 2. Asymmetrical FT was observed only in one (4.5%) vertebra. The mean diameter of FT was 6.2 mm in the right side and 6.4 mm in the left. CONCLUSION Double FT exists since the antiquity. The recognition of this variation provides safety and effectiveness for the posterior approaches of the cervical spine.