Sex and stature estimation on the tibia:a virtual pilot study on a contemporary Hispanic population

Sex and stature estimation represent two pillars in the creation of the biological profile, providing crucial demographic information that forensic anthropologists use for the identification of unknown skeletonized remains. This pilot study evaluates population data proposing a virtual sex and stature estimation method for a Hispanic population using the tibia. Ninety-two CT scans from the New Mexico Decedent Image Database were used to generate 3D models of the left tibia (forty-seven males, forty-five females). Tibial length, proximal and distal breadth were the parameters taken. Intra-observer error was assessed using an intra-class correlation coefficient. Sex differences were explored, and discriminant function and regression analysis used to develop sex and stature estimation formulae, respectively. High repeatability was demonstrated. Sex estimation accuracies ranged between 83.7 per cent and 93.5 per cent, with proximal and distal breadth showing the highest correct classification rates. Stature estimation produced errors between 5.51 cm and 7 cm, with the validation test providing errors falling within the predicted standard error of the estimate reported by the original equations. This study suggests the potential for accurate sex and stature estimation in the Hispanic sample. Although a larger sample is needed to corroborate the preliminary results, the proposed methods might assist in the identification of future forensic cases

Age estimation for two Mediterranean populations:rib histomorphometry applied to forensic identification and bone remodelling research

Numerous intrinsic and extrinsic factors influence bone remodelling rates and have shown to affect the accuracy of histological aging methods. The present study investigates the rib cortex from two Mediterranean skeletal collections exploring the development of population-specific standards for histomorphometric age-at-death estimation. Eighty-eight standard ribs from two samples, Cretans and Greek-Cypriots, were processed histologically. Thirteen raw and composite histomorphometric parameters were assessed and observer error tested. The correlation between age and the parameters and the differences between sex and population subsamples were explored through group comparisons and analysis of covariance. General linear models assessed through data fit indicators and cross-validation were generated from the total dataset, and by sex and population subsamples. Most of the histological variables showed a statistically significant correlation with age with some differences observed by sex and by sample. From the twelve models generated, the optimal model for the whole sample included osteon population density (OPD), osteon perimeter, and osteon circularity producing an error of 10.71 years. When sex and samples were separated, the best model selected included OPD and osteon perimeter producing an error of 8.07 years for Greek-Cypriots. This research demonstrates the feasibility of quantitative bone histology to estimate age, obtaining errors rates in accordance with macroscopic ageing techniques. Sex and sample population differences need further investigation and inter-population variation in remodelling rates is suggested. Moreover, this study contributes to the creation of population-specific standards for Cretans and Greek-Cypriots

Bone-mineral density: clinical significance, methods of quantification and forensic applications

Bone-mineral density (BMD) is a measure of the inorganic mineral content inbone, and is one of the more informative assessments of bone quality in both clinical studiesand forensic investigations. Several factors, such as age, sex, disease, genetics, and lifestyle,affect BMD measurements, and normative standards must be applied for specific groups andindividuals. One of the most common disorders associated with low BMD is osteoporosisand increased fracture risk, due to a decrease in bone strength and an increase in bonefragility. Medical conditions like diabetes or hyperthyroidism and other parameters like peakbone mass and postmenopausal estrogen deficiency also impact BMD. Single- and dual-energy photon absorptiometry, quantitative computet tomography, and magnetic resonanceimaging are some of the technological modalities for BMD quantification, and each presentsdistinct advantages and limitations, depending on the purpose of the analysis, the specificcharacteristics of the individual, the bone site under examination, and the equipment andtrained personnel available. Recently, BMD values were applied to forensic medicine in avariety of scenarios ranging from age and sex estimation to the assessment of malnutritionand the use offinite-element modelling. Despite technical and methodological inconsisten-cies reported in the literature on BMD readings, there is scope for expanding the use of thisvariable in forensic settings (4) (PDF) Bone-mineral density: clinical significance, methods of quantification and forensic applications. Available from: https://www.researchgate.net/publication/334676972_Bone-mineral_density_clinical_significance_methods_of_quantification_and_forensic_applications [accessed Aug 22 2019]

Sex estimation in a Turkish population using Purkait’s triangle: a virtual approach by 3-dimensional computed tomography (3D-CT)

Sex estimation is considered one of the first steps in the forensic identification process. Morphological and morphometrical differences between males and females have been used as means for morphoscopic and metric methods on both cranial and postcranial skeletal elements. When dry skeletal elements are not available, virtual data can be used as a substitute. The present research explores 3-dimensional (3D) scans from a Turkish population to test a sex estimation method developed by Purkait (2005). Overall, 296 individuals were used in this study (158 males and 138 females). Purkait’s triangle parameters were measured on computed tomography (CT) scans obtained from both right and left femora of each patient at the Bakirkoy Dr. Sadi Konuk Training Research Hospital (Istanbul, Turkey). Intra- and inter-observer errors were assessed for all variables through technical error of measurements analysis. Bilateral asymmetry and sex differences were evaluated using parametric and non-parametric statistical approaches. Univariate and multivariate discriminant function analyses were then conducted. Observer errors demonstrated an overall agreement within and between experts, as indicated by technical error of measurement (TEM) results. No bilateral asymmetries were reported, and all parameters demonstrated a statistically significant difference between males and females. Fourteen discriminant models were generated by applying single and combined parameters, producing a total correct sex classification ranging from 78.4% to 92.6%. In addition, over 67% of the total sample was accurately classified, with 95% or greater posterior probabilities. Our study demonstrates the feasibility of 3D sex estimation using Purkait’s triangle on a Turkish population, with accuracy rates comparable to those reported in other populations. This is the first attempt to apply this method on virtual data and although further validation and standardisation are recommended for its application on dry bone, this research constitutes a significant contribution to the development of population-specific standards when only virtual data are available

Metric variation of the tibia in the Mediterranean: implications in forensic identification

Ancestry estimation from skeletal remains is a challenging task, but essential for the creation of a complete biological profile. As such, the study of human variation between populations is important for the fields of biological and forensic anthropology, as well as medicine. Cranial and dental morphological variation have traditionally been linked to geographic affinity resulting in several methods of ancestry estimation, while the postcranial skeleton has been systematically neglected. The current study explores metric variation of the tibia in six Mediterranean populations and its validity in estimating ancestry in the Mediterranean. The study sample includes 909 individuals (470 males and 439 females) from Cyprus, Greece, Italy, Spain, Portugal and Turkey. The sample was divided in two subsamples: a reference and a validation sample. Multinomial regression models were created based on the reference sample and then applied to validation sample. The first model used three variables and resulted in 57% and 56% accuracy for the two samples respectively, while the second model (6 variables) resulted in 80% and 74% respectively. Classification between groups ranged from 28% to 95% for the reference sample and from 15% to 91% for the validation sample. The highest classification accuracy was noted for the Greek sample (95% and 90% for the reference and validation sample respectively), followed by the Turkish sample (74% and 78% respectively). The Spanish, Portuguese and Italian samples presented greater morphological overlap which resulted in lower classification accuracies. The results indicate that although the tibia presents considerable variation amongst neighbour populations is not suitable as a sole skeletal element to separate all groups successfully. A combination of different skeletal elements may be required in order to achieve the levels of reliability required for forensic applications

FORDISC® and AncesTrees:Limitations and Considerations for the Identification of Individuals From Central and South America

Learning Overview: The goal of this presentation is to present new data on population structure and population history from individuals from Central and South America through the interpretation of population-affinity estimations obtained by two online applications (FORDISC® and AncesTrees).Impact Statement: This presentation will impact the forensic science community by providing forensic practitioners with a theoretical and practical background for the application of two popular online softwares, FORDISC® and AncesTrees, targeting issues for population-affinity estimations on human remains from Central and South American. Extreme conditions leading to rapid skeletonization in some areas of the United States-Mexico border can make identification difficult. From the demographics gathered for biological profile estimation, biogeographical origin can impact the choice of subsequent methods for sex or age-at-death assessment. AncesTrees and FORDISC® are two computerized statistically based methods for estimating population affinity. To determine the reliability of group allocation using these applications, different target samples should be tested.The aim of this study is to explore the reliability of these applications in estimating the origin of individuals from Central and South America, comprising population groups that likely form the migratory flow prevalent across the United States-Mexico border. A total of 50 adult individuals (25 males and 25 females) identified as Mexican, Mexican American, Hispanic, New Mexican, or Latino were selected from the New Mexico Decedent Image Database. Seventeen cranial measurements were collected from Computed Tomography (CT) scans. Compiled measurements followed protocols outlined by AncesTrees and FORDISC®. Parameter values were inserted into the online platforms, with the settings for the application determined as non-prior background information.For FORDISC®, both the Howells’ and the Forensic Anthropology Data Bank (FDB) datasets were tested to explore any potential differences related to the chronology of the reference samples, as well as allowing for a comparison between AncesTrees and FORDISC® historical samples. All allocations are reported in the results, with Posterior Probability (PP) and Group Membership (GM) with values ≥0.80 being considered for further interpretation of the group allocation.Results show that AncesTrees allocated individuals as European (48%) and East Asian (32%), with the remaining biogeographical population sample allocations representing less than 10%. For the FORDISC® FDB, 26% of the sample was estimated as White and 24% of the sample was allocated as Hispanic, with the third-highest number of individuals being associated to Japanese (16%), Guatemalan (12%) and Chinese (12%) samples. Regarding the FORDISC® historical dataset, 24% of the individuals were classified as European with the next highest allocation being for East Asian samples (40%). Very few individuals obtained a PP higher than the threshold for FORDISC® estimations while GM for AncesTrees was over 0.80 for around 62% of the sampleAn accurate reconstruction of the biological profile is crucial for positive identification. Most of the population allocations obtained here using two commonly used online platforms present trends that suggest individuals from Central and South American origin would fall within Hispanic and European populations as well as East Asian samples. This research provides insights on population structure and population histories, as the patterns observed may be linked to social and political history. Future research, including larger and more diverse samples, will confirm our results and provide further information on human variation and inter-population differences.A consensus on the terminology as well as a revision of the information used for grouping the samples is recommended to ensure consistency between forensic practitioners and researchers. Moreover, larger and more representative datasets are needed to increase the accuracy and reliability of identification of unknown individuals in a forensic context, especially for areas with high migration flows such as the United States-Mexico border

FORDISC® and AncesTrees:Limitations and Considerations for the Identification of Individuals From Central and South America

Learning Overview: The goal of this presentation is to present new data on population structure and population history from individuals from Central and South America through the interpretation of population-affinity estimations obtained by two online applications (FORDISC® and AncesTrees).Impact Statement: This presentation will impact the forensic science community by providing forensic practitioners with a theoretical and practical background for the application of two popular online softwares, FORDISC® and AncesTrees, targeting issues for population-affinity estimations on human remains from Central and South American. Extreme conditions leading to rapid skeletonization in some areas of the United States-Mexico border can make identification difficult. From the demographics gathered for biological profile estimation, biogeographical origin can impact the choice of subsequent methods for sex or age-at-death assessment. AncesTrees and FORDISC® are two computerized statistically based methods for estimating population affinity. To determine the reliability of group allocation using these applications, different target samples should be tested.The aim of this study is to explore the reliability of these applications in estimating the origin of individuals from Central and South America, comprising population groups that likely form the migratory flow prevalent across the United States-Mexico border. A total of 50 adult individuals (25 males and 25 females) identified as Mexican, Mexican American, Hispanic, New Mexican, or Latino were selected from the New Mexico Decedent Image Database. Seventeen cranial measurements were collected from Computed Tomography (CT) scans. Compiled measurements followed protocols outlined by AncesTrees and FORDISC®. Parameter values were inserted into the online platforms, with the settings for the application determined as non-prior background information.For FORDISC®, both the Howells’ and the Forensic Anthropology Data Bank (FDB) datasets were tested to explore any potential differences related to the chronology of the reference samples, as well as allowing for a comparison between AncesTrees and FORDISC® historical samples. All allocations are reported in the results, with Posterior Probability (PP) and Group Membership (GM) with values ≥0.80 being considered for further interpretation of the group allocation.Results show that AncesTrees allocated individuals as European (48%) and East Asian (32%), with the remaining biogeographical population sample allocations representing less than 10%. For the FORDISC® FDB, 26% of the sample was estimated as White and 24% of the sample was allocated as Hispanic, with the third-highest number of individuals being associated to Japanese (16%), Guatemalan (12%) and Chinese (12%) samples. Regarding the FORDISC® historical dataset, 24% of the individuals were classified as European with the next highest allocation being for East Asian samples (40%). Very few individuals obtained a PP higher than the threshold for FORDISC® estimations while GM for AncesTrees was over 0.80 for around 62% of the sampleAn accurate reconstruction of the biological profile is crucial for positive identification. Most of the population allocations obtained here using two commonly used online platforms present trends that suggest individuals from Central and South American origin would fall within Hispanic and European populations as well as East Asian samples. This research provides insights on population structure and population histories, as the patterns observed may be linked to social and political history. Future research, including larger and more diverse samples, will confirm our results and provide further information on human variation and inter-population differences.A consensus on the terminology as well as a revision of the information used for grouping the samples is recommended to ensure consistency between forensic practitioners and researchers. Moreover, larger and more representative datasets are needed to increase the accuracy and reliability of identification of unknown individuals in a forensic context, especially for areas with high migration flows such as the United States-Mexico border

Joan Planells and Via Punica: Demographics of two archaeological populations from Ibiza

The anthropological information about past populations allows interpreting the past better and helps to understand biological aspects of the present populations. In this study, the demographics of two Roman archaeological populations from Ibiza are presented. Standard osteological methods are used to assess the populations’ biological profile. Sex and age assessment, stature and pathologies and traumatic lesions are reported. The analysis of cranial, postcranial and dental non-metrics traits skeleton is also undertaken. Overall, this provides valuable information about the Roman population from 1st to 7th centuries in the island