Browsing by Author "Dinkele, Elizabeth"

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    A pilot study on stature estimation of the South African male population using the post mortem Lodox® Xmplar-dr imaging device at the Salt River Forensic Medico-Legal Laboratory
    (2022) Venketsamy, Yomika; Heyns, Marise; Mole, Calvin; Dinkele, Elizabeth
    Identification of deceased individuals is of paramount importance in the South African constitution, with victim identification noted as a human right. Stature has been used to assist identification of an individual when skeletal remains are recovered. The usefulness of stature estimation using conventional x-rays, magnetic resonance imaging (MRI) and computed tomography (CT) measurements of long bones in a modern population has been researched in a number of countries, however, there has been limited research conducted on Lodox® bone scans as an added tool for stature estimation in the South African population. Forty-nine deceased males aged 21 to 61 years were scanned with Lodox® within 24 hours of entering Salt River Mortuary for a scheduled autopsy. Total stature was initially measured on the autopsy table with an embedded ruler. The body underwent a full body digital x-ray using the Lodox® Xmplar DR device. To measure length of bones on the Lodox® scans, full body images were exported in DICOM (Digital Imaging and Communication in Medicine) format and five long bone maximum lengths i.e. humerus, radius, ulna, femur and tibia of the bodies were digitally measured using the integrated Lodox® software. Lodox® image scan measurements found that the humerus, femur and tibia were the most statistically significant correlators of stature, individually. The univariate linear regression showed strong statistical significance for the humerus, femur and tibia with estimating stature. Multiple linear regression with the combination of humerus and ulna; femur and tibia; humerus, femur and tibia were statistically significant in determining stature. However, a combination of ulna and radius and the combination of all five bones overall regression was not statistically significant. Univariate and multiple linear regression formulas were created for the South African male population using Lodox® image scan measurements. Correlation and paired t-tests showed significant correlation between manual stature measurement at the mortuary and Lodox® measurements for stature.
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    Ancestral variation in mid-craniofacial morphology in a South African sample
    (2018) Dinkele, Elizabeth; Friedling, L Jacqui
    Ancestry estimation is a critical component of the demographic profile compiled by forensic anthropologists when unknown skeletal remains are discovered. The mid-craniofacial region is most frequently used to estimate ancestry as this region reflects the genetic and morphological ancestry of an individual. The diverse composition of the South African population makes ancestry estimation problematic, and necessitates the development of reliable, population-specific standards. This study sought to characterise variations in mid-craniofacial shape and size between South Africans of European ancestry (EA), African ancestry (AA) and Mixed ancestry (MA). Metric, nonmetric and geometric morphometric assessments were performed on 392 crania from skeletal collections in South Africa. Variations in mid-craniofacial shape and size were assessed in the orbital, nasal, zygomatic and maxillary regions in two-and three-dimensions. Univariate and multivariate statistical analyses were employed to characterise variation and estimate ancestry in AA, MA and EA individuals. Multivariate analyses suggest that tightly integrated ancestral variations in each component of the mid-craniofacial region are associated with functional, regional and developmental proximities of these regions. Specifically, AA individuals exhibited wider and shorter midfacial regions than EA individuals, who exhibited the narrowest orbital, zygomatic and nasal breadths and the longest upper facial, orbital and nasal heights. EA individuals exhibited inferiorly-angled orbits, elongated nasal apertures and anteriorly projecting nasal bridges. Rounder nasal apertures, less anteriorly projecting nasal bridges and more anteriorly projecting maxillary regions were detected in AA individuals. MA individuals exhibited heterogeneity in terms of craniofacial shape and size, and therefore produced the lowest ancestry estimation accuracies. Overall, nasal and maxillary regions were the most ancestrally diverse regions. Antemortem maxillary tooth loss and midfacial trauma were confounding factors in ancestry estimation accuracies. The lowest ancestry estimation accuracies were yielded by two-dimensional metric (27%-60.2%) and nonmetric (57.1%-82.4%) methods. Metric and geometric morphometric assessments yielded the highest repeatability (≥ 95%) indicating that these methods may be more reliable for use in medicolegal contexts. Geometric morphometric shape assessments yielded the highest ancestry estimation accuracies (75-97.9%), suggesting the presence of three dimensional shape variations between ancestry groups. These results suggest that a continuum of ancestral variation, with large areas of overlap, exists across South African populations and emphasises the need to develop multivariate ancestry estimation standards which can estimate ancestry reliably.
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    Assessing the accuracy of the zygoma for estimating ancestry using geometric morphometrics in a South African sample
    (2019) Tawha, Tafadzwa Primrose Rudo; Gibbon, Victoria E; Dinkele, Elizabeth; Mole, Calvin
    The large number of unidentified, decomposed and skeletonised remains found in South Africa (SA) necessitates relevant and reliable methods to assist in victim identification. Ancestry estimation from unknown skeletal remains is essential when reconstructing a demographic profile of a missing person. In the SA population, estimating ancestry is problematic as standards developed internationally rarely apply to the local, biologically heterogenous population. Craniofacial morphology is known to be ancestrally distinct and studies are yet to explore shape and size variation in the zygomatic bone of the SA population. The aim of this study was to assess ancestral variation in zygomatic shape and size in a SA population using three-dimensional geometric morphometric analyses. A sample of 158 individuals were analysed from Bantu-speaking (BA), European (EA) and Mixed Ancestral (MA) South African groups. Males were larger in size than females, but no size differences were observed between ancestral groups. Significant shape differences were observed between ancestral groups, while none were observed between males and females. BA and MA individuals had narrower, shorter and more anteriorly projecting zygomas than EA individuals. The zygoma was shown to accurately distinguish EA (84%) from BA (81%), and MA (80%) from EA (68%) individuals, but unreliably distinguished BA (60%) from MA (66%) individuals. This is likely correlated to the historical peopling of SA and historical forced racial classification. Age-related changes and antemortem tooth loss did not confound the ancestral variation in size, despite minor changes in zygomatic shape being associated with these two factors. These confounders did not impact ancestry estimation accuracies, further suggesting a minor impact on overall zygomatic shape. Furthermore, the patterning of ancestral variation in the zygoma revealed the need for further research to distinguish between the biologically heterogenous ancestral groups in SA.