ABSTRACT
Introduction: Lumbosacral transitional vertebra (LSTV) is one of recognized morphological variant associatedwith back pain. As sacrum has very crucial role in weight transmission via sacroiliac joint, any change inmorphology of auricular surface of sacrum should have impact in morphology of lumbosacral region.Aim: To study relation between the variable extent of auricular surface in Sacrum and prevalence of LumbosacralTransitional Vertebra (LSTV) along with changes in morphological index.Materials and Methods: Present study was done by taking total 40 adult dry human sacra of both sexes whichwere collected from the Department of Anatomy at Himalayan Institute of Medical Sciences, SRHU, Dehradun. Allsacra were initially divided into two sacral groups of normal sacra and atypical sacra based on absence andpresence of any type of lumbosacral transitional vertebra (LSTV) respectively. Further each group subcategorizedinto three, namely A (normal sacra), B (high sacra) and C (low sacra) based on extend of auricular surface. Metrictraits like maximum auricular length, maximum sacral length, maximum sacral width and sacral index weremeasured and compared.Result: In this study sacra with higher type of auricular surface were found to be associated with more incidenceof sacralization whereas sacra with lower type of auricular surface were associated with lumbarization. Therewas significant difference noticed in mean sacral index of these two sacral groups. Sacral index in sacral groupwith LSTV (Mean 95.06) was found to be less on comparing with sacral group without LSTV (Mean 108.20).Increased mean maximum sacral length (mean 109.62) seen in sacral group with LSTV without significantchange in maximum sacral width (mean 103.75) which can be due to shift of weight transmission axis from lowersacral vertebrae to higher vertebrae.Conclusion: Variable extents of auricular surface of sacrum are associated with variant of lumbosacral transitionvertebra due to change in biomechanics of weight transmission. Thus this study may be helpful to clinicians topredict and treat root cause of LSTV associated back pain.