IJSR International Journal of Scientific Research 2277 - 8179 Indian Society for Health and Advanced Research ijsr-6-7-11582 Original Research Paper Morphometric Analysis of the axis vertebra in Indian population: manoeuvring through the craniovertebral junction Rohit Pai Dr. Dr. Saurabh Satish Deshpande Dr. Dr.Ashwini P.Sankhe Dr. July 2017 6 7 01 02 ABSTRACT

 Aims: Axis vertebra (C2) is involved in various pathologies which lead to instability at the craniovertebral junction.  Pre–operative morphometric analysis of axis is important since various surgical interventions rely on different anatomical details which vary widely in the population. Methods: We retrospectively analyzed different radiological parameters of normal C2 vertebra in the CT scans of 100 subjects; namely anterior height of axis vertebra, its body and dens, Antero–posterior (AP) and transverse dimensions (TD) of dens, dens sagittal angle and various pedicle characteristics like pedicle width, height, pedicle superior angle (PSA) and pedicle median angle (PMA). Results: We found that the mean heights of axis vertebra, dens and body of axis were 31.07mm, 14.73mm and 16.33mm respectively. The mean AP and transverse diameters of dens were 10.82 mm and 9.8 mm respectively, with the mean dens sagittal angle being 16.02 degrees. The mean pedicle width and height were 7.06 mm and 7.86 mm respectively, pedicle superior angle and pedicle median angle were 26.04 degrees and 33.41 degrees respectively. We found that these parameters varied significantly in males and females (p<0.05), except dens sagittal angle (p=0.129) and pedicle superior angle (p=0.28). The number of subjects who had the minimum dens TD less than 9 mm were 35 % [10 males (21.7 %), 25 females (46.2 %)], being significantly more in females (p=0.01).  Conclusion: Morphometric analysis of axis vertebra assumes importance prior to all craniovertebral junction interventions since there is significant variation in its anatomical parameters in the population.