Sex estimation from the navicular bone in Spanish contemporary skeletal collections (original) (raw)
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Sex assessment of skeletal remains plays an important role in forensic anthropology. The pelvic bones are the most studied part of the postcranial skeleton for the assessment of sex. It is evident that a population-specific approach improves rates of accuracy within the group. The present study proposes a discriminant function method for the sex assessment of skeletal remains from a contemporary Mexican population. A total of 146 adult human pelvic bones (61 females and 85 males) from the skeletal series pertaining to the National Autonomous University of Mexico were evaluated. Twenty-four direct metrical parameters of coxal and sacral bones were measured and subsequently, sides and sex differences were evaluated, applying a stepwise discriminant function analysis. Coxal and sacra functions achieved accuracies of 99% and 87%, respectively. These analyses follow a population-specific approach; nevertheless, we consider that our results are applicable to any other Hispanic samples for purposes of forensic human identification. Sex estimation using human skeletal remains has long been a major focus of anthropological research, but in forensic science, it is a critical process with legal implications (1,2). Several methods have been developed which provide criteria for sex assessment, focusing on visual (3–10) and morphometric analyses (11–26) of the pelvis bones. A number of studies have been undertaken for the purpose of sex estimation using postcranial and craniofacial discriminant function analysis from Mexican samples (27–32). However, the pelvis has not been studied. Success rates for sex estimation are greater among adult individuals , because sexual differences in the skeleton are better defined than in immature specimens. The male pelvis is longer, robust, and displays more rugged features with marked muscle insertions. Males show a narrower sciatic notch with an acute angle, the ace-tabulum large and the pubis short with a narrower subpubic angle. In contrast, the female pelvis shows a wider sciatic notch with an obtuse angle. It has a preauricular sulcus, a smaller acetabulum, a longer pubis, and a wide subpubic angle (33). The pelvic girdle bones are structurally related to organ support and are functionally articulated to facilitate the erect position, as well as permitting the bipedal locomotion of the human body (34– 36). A particular characteristic of the pelvis is the configuration of an obstetrical ring, which is the main source of variation between sexes (37). The implication is that pelvic morphology has considerable potential for sex assessment, and for this purpose, in the present study, discriminant functions were developed. Materials and Methods The sample examined here derives from the Osteological Collection of the Anthropology Section, One hundred and forty-six human skeletons were examined (42% females and 58% males), ranging in age from 21 to >67 years old; all well-preserved and without any osteo-pathologies or postmortem modifications caused by peeling. The series corresponds to contemporary skeletons from unclaimed bodies recovered in diverse public health facilities (38). Following an agreement between the School of Medicine (UNAM), the Health Ministry and the Mexico City Government, the authors received permission to study the skeletons from the chief of the Anatomy Department who is officially responsible for the collection and has authorization from the Health Ministry. Using sliding and spreading calipers and an osteometric board; 24 direct metrical parameters relating to both coxal and sacrum bones were measured (Tables 1 and 2; Figs 1 and 2).
Utilizing foot bones for estimation of sex: a case study from modern Chilean adults
Journal of the Canadian Society of Forensic Science, 2021
ABSTRACT The estimation of sex is an important part of building the biological profile for unknown human remains. Many of the bones traditionally used for the estimation of sex are often found fragmented or incomplete in forensic and archaeological cases. The goal of this research is to derive population-specific discriminant functions from the talus, a preservationally favoured bone, for estimation of sex from a contemporary adult Chilean population. Nine parameters were measured from 220 individuals (113 males and 107 females) with age ranges from 15 to 78 years old. All nine tali variables were sexually dimorphic. Population-specific discriminant function equations were generated for use in sex estimation. Overall, the accuracy of sex classification ranged from 64.1% to 79.7% for the univariate analysis, 79.1% to 84.7% for the direct method, and 82.8% for the stepwise method. Comparisons to other populations were made and the results demonstrated the need for population-specific discriminant functions. Overall, the cross-validated accuracies ranged from 50% to 78%. The talus was shown to be useful for sex estimation in the modern Chilean population. RÉSUMÉ L’estimation du sexe est un élément important de la construction du profil biologique de restes humains non-identifiés. Dans les contextes médico-légaux et archéologiques, les ossements traditionnellement utilisés pour l’estimation du sexe sont le plus souvent retrouvés fragmentés ou incomplets. L’objectif de cette recherche est, pour une population spécifique, d’utiliser des analyses discriminantes basées sur le talus, généralement bien conservé, afin d’estimer le sexe sur une population chilienne adulte contemporaine. Neuf paramètres ont été mesurés sur un échantillon constitué de 220 individus (113 hommes et 107 femmes) âgés de 15 à 78 ans. Les neuf variables ont montré un dimorphisme sexuel. Des équations basées sur ces analyses discriminantes ont été générées pour être utilisées pour l’estimation du sexe. Dans l’ensemble, la précision de la classification par sexe variait de 64,1% à 79,7% pour l’analyse univariée, de 79,1% à 84,7% pour la méthode directe et était de 82,8% pour la méthode par étapes. Des comparaisons avec d’autres populations ont été réalisées et les résultats ont démontré la nécessité d’employer des analyses discriminantes spécifiques à la population. Globalement, les précisions obtenues par validation croisée variaient de 50% à 78%. Le talus s’est avéré utile pour l’estimation du sexe dans la population chilienne moderne.
2014
Physical secular changes in the human skeleton may interfere with the reliability of metric methods so these should be monitored from time to time to make sure that they are still up to date. In this research, sex estimation methods conventionally applied to the Portuguese population and developed on a collection from the 19th and early 20th centuries were tested in a sample of recently deceased individuals (N = 82) with the same ancestry composed of skeletons exhumed from the civil cemetery of Prado do Repouso (Porto). Referenced sex discriminating cut-off points were applied to the latter and the percentage of correct classification resulting from this procedure was calculated. A positive secular trend was found for the dimensions of most features that were investigated with clear implications for metric sex estimation. In comparison with the published values, the correct classification rates obtained on the modern sample were smaller in most cases. In particular, the results indicated that the use of established references for tarsal bones to sex estimate recent individuals is unadvisable. Therefore, new metric references developed on modern individuals are needed for the evaluation of remains from recent forensic contexts. Alternatively, when those are not available, more conservative interpretations of the results obtained through the application of outdated references are required when applied to modern individuals.
Sex estimation of adult skeletons is an important step in forensic analysis. Although the femur has been metrically studied for sex assessment around the world, very limited information is actually available on modern populations of Argentina. In this paper, the estimation of sex based on the metric evaluation of the superoinferior femoral neck diameter (SID) in a reference osteological collection from the contemporary Chacarita Cemetery of Buenos Aires City (Argentina), is evaluated. Protocols generated using SID in other three reference skeletal samples are also tested on this collection. One hundred and sixty-four individuals of both sexes and between 24 and 96 years old are analyzed. Inter and intra observer errors suggest that the replicability of the procedure is adequate. The sectioning point calculated from the direct measurements is 30.86 mm and results show a high degree of dimorphism. The proportions of correct sex discrimination and the likelihoods of correct allocation obtained with the direct measurements, along with the results of a discriminant function, a binary logistic regression and a Bayesian approach, are all higher than 0.85 (0.85-0.93 for females, 0.88-0.91 for males). When the formulae from other samples are used in the Chacarita Collection, the percentages of correct estimations range between 72.41% and 81.03% for females and between 80.46% and 88.50% for males, while the likelihoods are between 0.73 and 0.81 for females and between 0.79 and 0.82 for males. As the values for the estimations obtained using the statistical procedures generated in the present research are higher than those available for other collections, the method is more adequate to use in the analysis of contemporary skeletal remains from Buenos Aires and surrounding areas. The trends identified highlight the importance of populationspecific metric methodologies in forensic contexts and deserve future testing in contemporary samples from neighbouring regions.
Journal of forensic sciences, 2011
Abstract: Sex assessment of skeletal remains plays an important role in forensic anthropology. The pelvic bones are the most studied part of the postcranial skeleton for the assessment of sex. It is evident that a population-specific approach improves rates of accuracy within the group. The present study proposes a discriminant function method for the sex assessment of skeletal remains from a contemporary Mexican population. A total of 146 adult human pelvic bones (61 females and 85 males) from the skeletal series pertaining to the National Autonomous University of Mexico were evaluated. Twenty-four direct metrical parameters of coxal and sacral bones were measured and subsequently, sides and sex differences were evaluated, applying a stepwise discriminant function analysis. Coxal and sacra functions achieved accuracies of 99% and 87%, respectively. These analyses follow a population-specific approach; nevertheless, we consider that our results are applicable to any other Hispanic samples for purposes of forensic human identification.