Morphometric Study of Atlas Vertebra In Relation to Sulcus Arteriae Vertebralis

Abstract

Background: Atlas(C1) is an atypical cervical vertebra shaped like a ring. Important structures like the vertebral artery, suboccipital plexus of veins and first cervical nerve pass through it. Knowledge of the variability of C1 is important for neurosurgeons, orthopaedicians, otorhynologists and other physicians who in everyday practice are in contact with disorders of the spine and their consequences. So, this study was undertaken to assess the various dimensions of the C1 in relation to the vertebral artery groove. Methods and materials: fifty dried human atlas vertebrae were studied. Various measurements were done and statistically analysed. Results: Antero-posterior diameter (APD) of Foramen transversarium(FT) was measured as 7.73  1.04mm on the right and 7.62  0.90mm on left side. Transverse Diameter(TD) of FT was observed as 6.12  0.97mm on the right side and 6.02  0.97mm on the left side. Outer Distance of Vertebral Artery Groove(VAG) was measured as 26.22  2.32mm and 25.84  1.85mm on the right and left sides, respectively. Inner Distance of VAG was observed as 13.10  1.66mm on right and 13.17  1.57mm on the left side. APD of Superior Articular Facet(SAF) was 21.52  2.36mm on right and 21.51  2.07mm on left side.TD of SAF was 11.21  1.47mm on right and 11.32  1.53mm on left side. APD of Inferior Articular Facet(IAF) was observed as 17.54  1.50mm on right and 17.701.60mm on left side. TD of IAF was observed as 14.99 ± 1.65mm on the right side and 14.94 ± 1.51mm on left side. Distance between lateral-most edge of both Foramen Transversaria was measured as 56.37  4.11mm and distance between medial-most edge of both Foramen Transversaria was 44.78  3.67mm. MaximumTD of Atlas was measured as 72.09 5.59mm. Conclusion: The study will generate information that would be useful for geometric modelling of vertebrae and give necessary morphometric data on human atlas vertebra in Indian population. KEYWORDS: Atlas vertebra, Foramen transversarium, Vertebral Artery.