Skull Sutures: Radiographic Contour of Wormian Bone as an Individualising Epigenetic Marker

Prevalence of wormian bones worldwide: a critical review

Wormian bones (WB) are the irregular bone structures developed from additional centers of ossification. Although they are commonly found in healthy individuals, under certain conditions (number >10, mosaic pattern, large size), they can indicate pathology. While their coexistence with numerous diseases is well-documented, and various studies have reported their prevalence in populations of various geographic regions, no qualitative critical review of such studies has been conducted. The aim of this paper is to perform a critical review of research studies on the presence of Wormian bones in populations worldwide, with a particular emphasis on the methodology used and the selection of the samples studied. A sample of 44 original research articles was selected via PubMed and Google Scholar databases. Four criteria were assessed: 1) number of individuals in each group, 2) known sex of individuals, 3) selection criteria of individuals, and 4) implementation of the statistical analysis. The origin of the research sample was determined as well as the method of the WB calculation, and data on the WB prevalence worldwide was collected in tabular form. The reported size of the research samples varies from 22 to 628 individuals, derived from both contemporary and archaeological populations. Four major formulas were used in order to provide the frequency of WB. The sex of individuals was known in 18 (40.9%) articles. Most of the articles focused on Asian samples. The difficulties in comparing data on the Wormian bones are caused by considerable inconsistency in the methodology used to research this phenomenon. Therefore, the interpopulation comparisons currently made may not be correctly estimated. Our study highlights the need for using more comprehensive and consistent data collection as well as processing protocol suitable for populational research on sutural bones.

Pitfalls of Computed Tomography 3D Reconstruction Models in Cranial Nonmetric Analysis

Many studies in the literature have highlighted the utility of virtual 3D databanks as a substitute for real skeletal collections and the important application of radiological records in personal identification. However, none have investigated the accuracy of virtual material compared to skeletal remains in nonmetric variant analysis using 3D models. The present study investigates the accuracy of 20 computed tomography (CT) 3D reconstruction models compared to the real crania, focusing on the quality of the reproduction of the real crania and the possibility to detect 29 dental/cranial morphological variations in 3D images. An interobserver analysis was performed to evaluate trait identification, number, position, and shape. Results demonstrate a false bone loss in 3D models in some cranial regions, specifically the maxillary and occipital bones in 85% and 20% of the samples. Additional analyses revealed several difficulties in the detection of cranial nonmetric traits in 3D models, resulting in incorrect identification in circa 70% of the traits. In particular, pitfalls included the detection of erroneous position, error in presence/absence rates, in number, and in shape. The lowest percentages of correct evaluations were found in traits localized in the lateral side of the cranium and for the infraorbital suture, mastoid foramen, and crenulation. The present study highlights important pitfalls in CT scan when compared with the real crania for nonmetric analysis. This may have crucial consequences in cases where 3D databanks are used as a source of reference population data for nonmetric traits and pathologies and during bone-CT comparisons for identification purposes.

Cranio-facial morphanalysis: a new method for enhancing reliability while identifying skulls by photo superimposition

Skull-photograph superimposition continues to be the most prevalent method employed for identifying a skull recovered in a criminal case as that belonging to a putative victim whose face photograph is available. The reliability of identification achieved has been shown to be 91%, indicating the possibility of a skull mismatching with a face photograph belonging to a person other than the actual deceased. This lack of reliability dampens the confidence of the expert and in turn confounds the mind of the judge. It has been shown that the variations in the shape of the facial organs are influenced by the corresponding variations in the skeletal elements of the facial skull. "Cranio-facial morphanalysis", a new anthroposcopic method proposed here for evaluating the shape correlations between a skull and a face photograph, when applied conjointly with skull-photograph superimposition is shown to increase the reliability in forensic skull identification.