Human interparietal bones: Examination of existing classification schemes and development of a graphic library depicting variations.

Abstract

Due to its complex ossification during development, the superior region of the human occipital bone is a frequent site of supernumerary bones known as interparietal bones. Interparietal bones have been extensively studied across various disciplines, resulting in multiple classification schemes using icon-like graphics to represent categories of interparietal variants. However, disparities across these classification schemes reveal the need for a standardized system to facilitate comparisons and permit data pooling across studies. Based on an extensive literature review and the examination of physical specimens, a graphic library of 80 evidence-based graphics capturing interparietal variants was designed for community use. It provides five graphics of different morphologies of the lambdoid suture, 64 graphics of interparietal bones, six of ossicles at lambda, three of mendosal suture variants, and two of intrasutural ossicles. This approach allows additional graphics to be added in the future as needed. Graphics are compared to those from existing classification schemes and an exercise using the graphics to classify crania was performed. In the broadest sense, this research establishes a model for improved practices in representing and sharing morphological data.