Morphometric Study of Foramina Transversaria in Cervical Vertebrae and its Clinical Significance

Abstract

Introduction: The characteristic feature of the cervical vertebrae is the presence of Foramen Transversarium (FT) in the transverse process. This foramen usually contains vertebral artery (except in C7 vertebra), veins and sympathetic plexus. The deformity and variations of this foramen may result in derangement of neurovascular structures passing through it, which may lead to various symptoms. The aetiology of morphological variations is related to developmental factors, mechanical stress and variations in the course of vertebral artery. Some studies have been done on accessory FT, but few give detailed analysis of morphometric variations of FT in cervical vertebrae. Aim: The aim of the study was to examine the morphological and morphometric variations in the FT of cervical vertebrae (typical and atypical). Materials and Methods: This was a retrospectively designed osteological observational study. The duration of the study was six months, from Dec 2019 to May 2020. The study was conducted on 750 cervical vertebrae (265 typical and 485 atypical). In each cervical vertebrae, the FT was observed for the following parameters; shape, size, maximum anteroposterior diameter, maximum transverse diameter, area and number. Digital vernier caliper was used for morphometric measurements. Photographs were taken and archived. Descriptive analysis and evaluation was done with SPSS statistics programme. results: In 300 (40%) vertebrae, shape of the FT was bilaterally symmetrical and in 450 (60%) vertebrae, it was asymmetrical on both sides. It was observed that maximum anteroposterior diameter and transverse diameter were seen in C1 vertebrae. There was no significant statistical difference between the mean diameters of the left and right side. Maximum area was also seen in C1 vertebrae, with values of 34.76 mm2 on left and 34.84 mm2 on right. Out of the 750 cervical vertebrae, 113 (15%) showed an accessory FT in the transverse process. Amongst these, in 30 (4%) cervical vertebrae, the accessory FT were present bilaterally and in 83 (11%) seen on one side only. conclusion: The present study demonstrates that different cervical vertebrae (typical and atypical) show considerable morphological variations in terms of shape, size, area and number of FT. Awareness of such variations is of significance to anatomists, clinicians and surgeons.