Sex Of Skeletal Remains Research Articles

Radiographic pelvimetry in free-ranging Eurasian lynx (Lynx lynx carpathicus) from Switzerland

The observation of pelvic anomalies in two Eurasian lynx (subspecies Lynx lynx carpathicus) from a population reintroduced to Switzerland raised the question of the frequency of such anomalies, but no anatomical reference values were available for comparison. This study aimed at providing baseline data on the pelvic morphology of Carpathian lynx from Switzerland, and at detecting potential pelvic anomalies. Measurements of 10 pelvic parameters were performed on the radiographs of 56 lynx taken from 1997–2015. Two ratios (vertical diameter/acetabula; sagittal diameter/transversal diameter) and two areas (pelvic outlet and inlet) were calculated to describe pelvic shape. The results showed that the Eurasian lynx has a mesatipellic pelvis, with a pelvic length corresponding to approximatively 20% of the body length. We found growth-related pelvis size differences among age classes and evidence of sexual dimorphism in adults: two parameters reflecting pelvic width were larger in females, likely to meet the physiological requirements of parturition. By contrast, pelvis length, conjugata vera, diagonal conjugata, sagittal diameter, and tendentially also vertical diameter, were larger in males, in agreement with their larger body size. Outliers were found in five individuals but apparently without clinical significance. Extreme values were likely due to inter-individual differences and the limited sample size rather than to possible congenital or developmental pathological morphology of the pelvic cavity. We present baseline data of the pelvic morphology, including growth and sexual dimorphism, which may be useful for health monitoring and for determination of age and sex in skeletal remains of Carpathian lynx.

Study of the K-S distance on skulls from different modern populations for sex and ancestry determination

AbstractIn forensic science determination of the origin and sex of skeletal remains is an important task for identification purposes. In this study we investigated the krotaphion-sphenion distance (K‑S distance) in the pterion region of German, Euro-American, African-American and Rwandan skulls of modern individuals from the nineteenth to the twenty-first century to look for statistically significant differences in sex and ancestry. We found a statistically significant sex-specific difference in the K‑S distance, which was greater in male skulls than in female skulls for both sides of the skull. Our study also showed that there is a statistically significant difference in the K‑S distance between the four populations studied. Landmarks and morphometric parameters measured in our investigations, which were not used for the present examination were provided to the software program Fordisc for its reference data to enhance the range of its usability for identification of unknown skulls or partial skulls of European individuals.

Sex estimation from reconstructed scapula models using discriminant function analysis in the Malaysian population

ABSTRACT Scapulae have been widely studied for its potential in differentiating sex in skeletal remains, especially when traditionally used sexually dimorphic bones were not available. The present work aimed to investigate sexual dimorphism of scapulae, and to develop and validate the population-specific metric standards of the Malaysian population using three-dimensional (3D) computed tomographic (CT) scapula models. Each scapula was measured for five variables with a digital caliper and analysed for independent T-test and discriminant analysis, where a leave-one-out cross-validation was applied. Moreover, a set of different samples (hold-out sample) was used to validate the established discriminant functions (DF). Consequently, all measurements showed significant differences between males and females (p < 0.001) and morphological breadth was discovered as the most sexually dimorphic scapulae measurements. Six DFs with classification accuracy ranging from 84.4% to 93.1% were generated. From the functions, stepwise DF predicted the highest classification accuracy. Additionally, the stepwise DF exhibited 95% classification accuracy when tested on the hold-out sample compared to univariate DFs which showed 82.5–92.5% accuracy. In conclusion, the virtual 3D scapulae models were sexually dimorphic, and the discriminant functions were significant in identifying skeletonized remains using scapulae bone in the Malaysian population.

Determination of sex from the morphometry of orbits in adult skull of contemporary eastern Indian population

BackgroundDetermination of sex from the structure of orbits in the human skull is well documented. Both morphology and morphometry of the orbits have application in the determination of sex in skeletal remains. These parameters are often population-specific and warrant research on a regional basis. The present study was conducted to examine the sexual dimorphism of orbits in eastern Indian population. It was designed with the objective to determine the sex of the skull from the linear dimensions of orbits by deriving a specific multivariate function for classification.Materials and methodsThe investigation was conducted on a series of 92 human skulls (61 males and 31 females). The orbital height (OH) and breadth (OB) were measured by using digital vernier calliper. Data analysis was performed by computing descriptive statistics like mean, standard deviation and range. Linear discriminant function analysis was carried out to derive a classification model.ResultsIt was noted that the orbital dimensions were more in females than in males. A multivariate function was derived from the discriminant function analysis. The estimated sectioning point or cut off score was calculated to be -0.141. If the score of the function was more than -0.141, then sex can be assigned as male. On the other hand, if it was less than -0.141, then it was female. Likewise, sex could be correctly assigned in 68.5% of the cases by this method.ConclusionThis study provides useful baseline orbital morphometric data for East Indian population. When applied in sex determination, this multivariate model returns 68.5% correct classification. It will be useful and easy population-specific method of sex determination from human skulls. This morphometric data can be used in further forensic research involving identification from skeletal remains.

Geometric morphometrics on juvenile crania: Exploring age and sex variation in an Australian population

For medico-legal forensic practitioners the identification of unknown remains is an important part of any investigation, often predicated on having accurate estimations of age and sex. In considering the specific skeletal elements available to facilitate such biological information, the cranium is frequently targeted for analysis, as it exhibits marked traits of sexual dimorphism, and also has a predictable pattern of growth. There are, however, instances where it may not be possible to estimate skeletal sex, especially in the juvenile skeleton. There is still considerable uncertainty surrounding the age at which the human cranium is quantifiably dimorphic. The aim of the present study is to explore age and sex variation in three-dimensionally reconstructed MDCT scans of the juvenile cranium. The study sample comprises 152 juvenile crania from a Western Australian population; a total of 52 three-dimensional landmarks are acquired and analyzed using Procrustean geometric morphometrics. Group discrimination is assessed between sexes and across age classes.Results demonstrate that sexual dimorphism and age variation is discernible through geometric morphometric analysis of form, size and shape. Relative to sex and age, size is found to be generally equivalent to, or even more accurate than, shape data. There is little quantifiable sexual dimorphism in individuals younger than 12years of age with most variation related to age; discrimination improves with increasing age, with average hit rate (HR) values increasing from just over 50% (52–58%) to more than 90% (93–94%) accuracy at 18years. In contrast, differences between contiguous age classes follow the opposite trend and tend to be larger in prepubertal groups, while becoming progressively smaller in older age classes.This study demonstrates that simple linear interlandmark distances describing overall cranial size may provide a simple option for preliminary classifications of age and sex in skeletal remains of forensic interest. However, although recombining size and shape to perform analyses using form generally does not appreciably improve predictive accuracy, it potentially contributes to increased confidence in group assessment (especially for sex) and thus offers a promising, albeit complex, type of information to discriminate groups based on cranial size and/or shape.

Sex and age at death estimation from the sternal end of the fourth rib. Does Íşcan's method really work?

The fourth rib has been used commonly in order to estimate age at death and even sex in skeletal remains but many often, Iscan's estimates do not adjust to the real age of the individual. Population specific references for sex and age-at-death estimation from the sternal end of the fourth rib are presented for a contemporary Mexican sample. A total of 504 ribs with known sex and age from a morgue sample were studied (444 males, 60 females, 17 to 92 years old). The height and breadth of the sternal end of the rib were sexually dimorphic (p = .000), and allowed a correct sex assignment in 73.3% to 84% of the cases from univariate and multivariate discriminant functions. With regard to age-at-death estimation, the morphological changes summarized by the phases of the sternal end of the fourth rib are correlated with known age in this sample (Spearman's Rho, p = .000). However, the original age intervals tend to underestimate age at death and inaccuracy increases with phase scored in males. Descriptive statistics for rib phase are provided for males and females, and new age-at-death estimates based on transition analysis and Bayesian statistics are provided for the male sample. The test of universally applied methods and the development of population specific references is an important task for forensic anthropology around the world.

Sex determination from the femur in Portuguese populations with classical and machine-learning classifiers

The assessment of sex is of paramount importance in the establishment of the biological profile of a skeletal individual. Femoral relevance for sex estimation is indisputable, particularly when other exceedingly dimorphic skeletal regions are missing. As such, this study intended to generate population-specific osteometric models for the estimation of sex with the femur and to compare the accuracy of the models obtained through classical and machine-learning classifiers. A set of 15 standard femoral measurements was acquired in a training sample (100 females; 100 males) from the Coimbra Identified Skeletal Collection (University of Coimbra, Portugal) and models for sex classification were produced with logistic regression (LR), linear discriminant analysis (LDA), support vector machines (SVM), and reduce error pruning trees (REPTree). Under cross-validation, univariable sectioning points generated with REPTree correctly estimated sex in 60.0–87.5% of cases (systematic error ranging from 0.0 to 37.0%), while multivariable models correctly classified sex in 84.0–92.5% of cases (bias from 0.0 to 7.0%). All models were assessed in a holdout sample (24 females; 34 males) from the 21st Century Identified Skeletal Collection (University of Coimbra, Portugal), with an allocation accuracy ranging from 56.9 to 86.2% (bias from 4.4 to 67.0%) in the univariable models, and from 84.5 to 89.7% (bias from 3.7 to 23.3%) in the multivariable models. This study makes available a detailed description of sexual dimorphism in femoral linear dimensions in two Portuguese identified skeletal samples, emphasizing the relevance of the femur for the estimation of sex in skeletal remains in diverse conditions of completeness and preservation.

A method for sex estimation using the proximal femur

The assessment of sex is crucial to the establishment of a biological profile of an unidentified skeletal individual. The best methods currently available for the sexual diagnosis of human skeletal remains generally rely on the presence of well-preserved pelvic bones, which is not always the case. Postcranial elements, including the femur, have been used to accurately estimate sex in skeletal remains from forensic and bioarcheological settings. In this study, we present an approach to estimate sex using two measurements (femoral neck width [FNW] and femoral neck axis length [FNAL]) of the proximal femur. FNW and FNAL were obtained in a training sample (114 females and 138 males) from the Luís Lopes Collection (National History Museum of Lisbon). Logistic regression and the C4.5 algorithm were used to develop models to predict sex in unknown individuals. Proposed cross-validated models correctly predicted sex in 82.5–85.7% of the cases. The models were also evaluated in a test sample (96 females and 96 males) from the Coimbra Identified Skeletal Collection (University of Coimbra), resulting in a sex allocation accuracy of 80.1–86.2%. This study supports the relative value of the proximal femur to estimate sex in skeletal remains, especially when other exceedingly dimorphic skeletal elements are not accessible for analysis.

A Study on Sacral Index in Tamil Nadu and Andhra Pradesh Population of Southern India

Human sacral bones are of great interest to the anatomists, forensic experts and anthropologists as it is one of the important bones used for identification of sex in skeletal remains. Various parameters and indices are available based on which the sex can be determined using sacrum. One such important parameter is the SI. Studies shows that SI significantly varies among male and female gender and among different populations. The calculation of Demarcation Point (DP) of SI increases the accuracy of identification of sex. A review of literature showed that many studies are available in the North Indian population whereas there is a dearth of information about the normal SI and DP in South Indian population particularly in the Tamil Nadu and Andhra Pradesh, Inida region. Therefore, the present study aims to create a database for the SI in the above mentioned population. One hundred twenty three bones of known sex (63 males and 60 females) belonging to Tamil Nadu and Andhra Pradesh, India region were studied. Bones with obvious pathology were excluded. The breadth and length of the sacra were measured using vernier calipers based on standard guidelines. The SI and DP were calculated. The statistical analysis was done using SPSS 15.0 package. The mean SI for male and female sacra were found to be 96.32 + 5.40 and 102.92 +4.00 respectively. The Demarcating Point was found to be <90.29 in males and >112.43 in females. The mean length of male and female sacra was 97.8 mm and 90.6mm respectively. The mean width was 93.7mm and 92.91mm respectively for males and females. The average SI and DP identified in the present study would be of use to the anatomists, forensic experts and anthropologists of Tamil Nadu and Andhra Pradesh population.

Sexual Dimorphism of the Arm Bones in a Modern Greek Population

Several studies have shown that sex determination methods based on measurements of the skeleton are population specific. Metric traits of the long bones of the arm have been reported as reliable indicators of sex. This study was designed to determine whether the three long bones of the arm can be used for sex determination on a skeletal population from Greece. The material used consists of the arm bones of 204 adult individuals (111 males and 93 females) coming from the Modern Human Skeletal Collection of the University of Athens. The age range is 19-96 years for males and 20-99 years for females. The maximum lengths and epiphyseal widths were measured in the long bones of the arm (humerus, radius, and ulna). The discriminant analysis of the metrical data of each long bone gave very high discrimination accuracies. The rate of correct sex discrimination based on different long bones ranges from 90.30% (ulna) to 95.70% (humerus). In addition, intra- and inter-observer error tests were performed. These indicated that replication of measurements was satisfactory for the same observer over time and between observers. The results of this study show that metric characteristics of the arm bones can be used for the determination of sex in skeletal remains from Greece and that bone dimensions are population specific.

Sex determination using metatarsal osteometrics from the Athens collection

The determination of sex in skeletal remains performed by forensic anthropologists or bioarchaeologists typically relies on the analysis of quantitative and qualitative characteristics of the skeleton. In this regard, the most widely used features belong to the pelvic and cranial areas, but these are often not available in forensic or archaeological contexts. The objective of this study is to determine the extent of dimorphism exhibited by the metatarsal bones in order to examine their utility in the metric determination of sex in skeletal remains of Greek origin. A further objective is the development of linear discriminant function equations for sex determination based on the metatarsals from a contemporary Greek population. The skeletal sample used in this study is comprised of 1595 metatarsals (left and right), corresponding to 186 adult individuals (97 males, 89 females) and belongs to the documented collection of the University of Athens. The results suggest that metatarsal bones exhibit significant sexual dimorphism and the accuracy of the discriminant function equations for sex determination range from 80.7% to 90.1% (or 77.9–86.4% cross-validated). Thus, metatarsal bones may be used for sex determination in skeletal remains from Greece in addition to other sexing techniques.