Implications of structural variations in the human sacrum: why is an anatomical classification crucial?

Abstract

An array of diversity in sacral anatomy including lumbosacral transitional variations is commonly found in the general population. These anatomical variations involve alterations in number of sacral segments, auricular surface area, and neural arch dimensions and are associated with biomechanical, surgical and obstetric implications. The present study reports screening >300 dried human sacral specimens and grouping them based on the common variations observed specifically in context of the number of sacral segments, position of the auricular surfaces, and type of the neural arch components. Screening and grouping of the samples presented a five-group classification and coding system that incorporates specific structural characteristic in a sacrum. The grouping and coding system developed in this study classifies variabilities associated with sacral anatomy along a common-to-rare anatomical spectrum that may provide handy information needed in a clinical, biomechanical, obstetric or medico-legal context.