Virtual morphometric method using seven cervical vertebrae for sex estimation on the Turkish population.

Sex estimation from skeletal remains is crucial for the estimation of the biological profile of an individual. Although the most commonly used bones for means of sex estimation are the pelvis and the skull, research has shown that acceptable accuracy rates might be achieved by using other skeletal elements such as vertebrae. This study aims to contribute to the development of sex estimation standards from a Turkish population through the examination of CT scans from the seven cervical vertebrae. A total of 294 individuals were included in this study. The CT scans were obtained from patients attending the Bakirkoy Training and Research Hospital (Turkey) and the data was collected retrospectively by virtually taking measurements from each cervical vertebrae. The full database was divided into a training set (N = 210) and a validation set (N = 84) to test the fit of the models. Observer error was assessed through technical error of measurement and sex differences were explored using parametric and non-parametric approaches. Logistic regression was applied in order to explore different combinations of vertebral parameters. The results showed low intra- and inter-observer errors. All parameters presented statistically significant differences between the sexes and a total of 15 univariate and multivariate models were generated producing accuracies ranging from a minimum of 83.30% to a maximum of 91.40% for a model including three parameters collected from four vertebrae. This study presents a virtual method using cervical vertebrae for sex estimation on the Turkish population providing error rates comparable to other metric studies conducted on the postcranial skeleton. The presented results contribute not only to the development of population-specific standards but also to the generation of virtual methods that can be tested, validated, and further examined in future forensic cases.

Sex Determination of Three-Dimensional Skull Based on Improved Backpropagation Neural Network.

Sex determination from skeletons is a significant step in the analysis of forensic anthropology. Previous skeletal sex assessments were analyzed by anthropologists' subjective vision and sexually dimorphic features. In this paper, we proposed an improved backpropagation neural network (BPNN) to determine gender from skull. It adds the momentum term to improve the convergence speed and avoids falling into local minimum. The regularization operator is used to ensure the stability of the algorithm, and the Adaboost integration algorithm is used to improve the generalization ability of the model. 267 skulls were used in the experiment, of which 153 were females and 114 were males. Six characteristics of the skull measured by computer-aided measurement are used as the network inputs. There are two structures of BPNN for experiment, namely, [6; 6; 2] and [6; 12; 2], of which the [6; 12; 2] model has better average accuracy. While η = 0.5 and α = 0.9, the classification accuracy is the best. The accuracy rate of the training stage is 97.232%, and the mean squared error (MSE) is 0.01; the accuracy rate of the testing stage is 96.764%, and the MSE is 1.016. Compared with traditional methods, it has stronger learning ability, faster convergence speed, and higher classification accuracy.

Towards a new osteometric method for sexing ancient cremated human remains. Analysis of Late Bronze Age and Iron Age samples from Italy with gendered grave goods.

Sex estimation of human remains is one of the most important research steps for physical anthropologists and archaeologists dealing with funerary contexts and trying to reconstruct the demographic structure of ancient societies. However, it is well known that in the case of cremations sex assessment might be complicated by the destructive/transformative effect of the fire on bones. Osteometric standards built on unburned human remains and contemporary cremated series are often inadequate for the analysis of ancient cremations, and frequently result in a significant number of misclassifications. This work is an attempt to overcome the scarcity of methods that could be applied to pre-proto-historic Italy and serve as methodological comparison for other European contexts. A set of 24 anatomical traits were measured on 124 Bronze Age and Iron Age cremated individuals with clearly engendered grave goods. Assuming gender largely correlated to sex, male and female distributions of each individual trait measured were compared to evaluate sexual dimorphism through inferential statistics and Chaktaborty and Majumder's index. The discriminatory power of each variable was evaluated by cross-validation tests. Eight variables yielded an accuracy equal to or greater than 80%. Four of these variables also show a similar degree of precision for both sexes. The most diagnostic measurements are from radius, patella, mandible, talus, femur, first metatarsal, lunate and humerus. Overall, the degree of sexual dimorphism and the reliability of estimates obtained from our series are similar to those of a modern cremated sample recorded by Gonçalves and collaborators. Nevertheless, mean values of the male and female distributions in our case study are lower, and the application of the cut-off point calculated from the modern sample to our ancient individuals produces a considerable number of misclassifications. This result confirms the need to build population-specific methods for sexing the cremated remains of ancient individuals.

The Influence of Body Size on the Expression of Sexually Dimorphic Morphological Traits.

Skeletal sexual dimorphism manifests as size or shape differences between males and females in a population. Certain dimorphic traits are used in sex estimation methods, and populational variation in the expression of these traits can result in inaccurate sex estimation. However, the underlying causes of variation in trait expression remain unclear. This study explores body size, which also exhibits sexual dimorphism, as a potential factor influencing trait expression. To test this, skeletons of 209 individuals of varying body size were analyzed, and morphological traits were scored according to the Walker (2008), Klales et al. (2012), and Rogers (1999) sex estimation methods. Statistical analyses found significant correlations between body size parameters and expression of traits, with stature explaining more relative variance in trait expression than body mass. However, the relationships are weak and few in number, suggesting that body size has a minimal impact on the expression of these morphological traits.

Evaluating macroscopic sex estimation methods using genetically sexed archaeological material: The medieval skeletal collection from St John's Divinity School, Cambridge.

OBJECTIVES: In tests on known individuals macroscopic sex estimation has between 70% and 98% accuracy. However, materials used to create and test these methods are overwhelming modern. As sexual dimorphism is dependent on multiple factors, it is unclear whether macroscopic methods have similar success on earlier materials, which differ in lifestyle and nutrition. This research aims to assess the accuracy of commonly used traits by comparing macroscopic sex estimates to genetic sex in medieval English material. MATERIALS AND METHODS: Sixty-six individuals from the 13th to 16th century Hospital of St John the Evangelist, Cambridge, were assessed. Genetic sex was determined using a shotgun approach. Eighteen skeletal traits were examined, and macroscopic sex estimates were derived from the os coxae, skull, and os coxae and skull combined. Each trait was tested for accuracy to explore sex estimates errors. RESULTS: The combined estimate (97.7%) outperformed the os coxae only estimate (95.7%), which outperformed the skull only estimate (90.4%). Accuracy rates for individual traits varied: Phenice traits were most accurate, whereas supraorbital margins, frontal bossing, and gonial flaring were least accurate. The preauricular sulcus and arc compose showed a bias in accuracy between sexes. DISCUSSION: Macroscopic sex estimates are accurate when applied to medieval material from Cambridge. However, low trait accuracy rates may relate to differences in dimorphism between the method derivative sample and the St John's collection. Given the sex bias, the preauricular sulcus, frontal bossing, and arc compose should be reconsidered as appropriate traits for sex estimation for this group.

Sex determination by three-dimensional geometric morphometrics of the vault and midsagittal curve of the neurocranium in a modern Greek population sample.

The aim of this study is to assess sexual dimorphism of adult crania in the vault and midsagittal curve of the vault using three-dimensional geometric morphometric methods. The study sample consisted of 176 crania of known sex (94 males, 82 females) belonging to individuals who lived during the 20th century in Greece. The three-dimensional co-ordinates of 31 ecto-cranial landmarks and 30 semi-landmarks were digitized using a MicroScribe 3DX contact digitizer. Generalized Procrustes analysis (GPA) was used to obtain size and shape variables for statistical analysis. Shape, size and form analyses were carried out by logistic regression and three discriminant function analyses. Results indicate that there are shape differences between sexes. Females in the region of the parietal bones are narrower and the axis forming the frontal and occipital bones is more elongated; the frontal bone is more vertical. Sex-specific shape differences give better classification results in the vault (79%) compared with the midsagittal curve of the neurocranium (68.8%). Size alone yielded better results for cranial vault (82%), while for the midsagittal curve of the vault the result is poorer (68.1%). As anticipated, the classification accuracy improves when both size and shape are combined (89.2% for vault, and 79.4% for midsagittal curve of the vault). These latter findings imply that, in contrast to the midsagittal curve of the neurocranium, the shape of the cranial vault can be used as an indicator of sex in the modern Greek population.

Automatic sex determination of skulls based on a statistical shape model.

Sex determination from skeletons is an important research subject in forensic medicine. Previous skeletal sex assessments are through subjective visual analysis by anthropologists or metric analysis of sexually dimorphic features. In this work, we present an automatic sex determination method for 3D digital skulls, in which a statistical shape model for skulls is constructed, which projects the high-dimensional skull data into a low-dimensional shape space, and Fisher discriminant analysis is used to classify skulls in the shape space. This method combines the advantages of metrical and morphological methods. It is easy to use without professional qualification and tedious manual measurement. With a group of Chinese skulls including 127 males and 81 females, we choose 92 males and 58 females to establish the discriminant model and validate the model with the other skulls. The correct rate is 95.7% and 91.4% for females and males, respectively. Leave-one-out test also shows that the method has a high accuracy.

Geometric morphometric assessment of sexually dimorphic characteristics of the distal humerus.

A number of recent studies investigated the use of morphological characteristics of the distal humerus to estimate the sex of unknown individuals. Using visual assessment, accuracies ranging from 74% to more than 90% were reported. The aim of this study was to assess these traits with geometric morphometrics, in order to determine if they corroborate the findings described with pure visual assessment. A total sample of 155 female and 175 male humeri of South Africans were used. All humeri were photographed in standardized positions from a posterior and inferior view, and homologous landmarks assigned. Olecranon fossa shape, angle of the medial epicondyle and trochlear symmetry were assessed. Males and females could be separated with accuracies ranging from 78% to 91%. The results of this study confirm the existence of these traits and their usability in assessment of sex from skeletal remains, and the observed anatomical characteristics largely agree with what have been described by visual assessment.

Evaluation of foramen magnum in gender determination using helical CT scanning.

OBJECTIVE: The present research was undertaken to study the accuracy and reliability of the foramen magnum (FM) and some cranial measurements in gender classification through the use of reconstructed helical CT images. METHODS: 88 patients (43 males and 45 females; age range, 20-49 years) were selected for this study. FM sagittal diameter, transverse diameter, area and circumference were measured and data were subjected to discriminant analysis for gender using multiple regression analysis. RESULTS: FM circumference and area were the best discriminant parameters that could be used to study sexual dimorphism with an overall accuracy of 67% and 69.3%, respectively. By using multivariate analysis, 90.7% of FM dimensions of males and 73.3% of FM dimensions of females were sexed correctly. CONCLUSION: It can be concluded that the reconstructed CT image can provide valuable measurements for the FM and could be used for sexing when other methods are inconclusive.

Sex estimation of the Cretan humerus: a digital radiometric study.

Sex estimation based on measurements of unidentified skeletal remains recovered in crime and death scenes can be accomplished with accuracy. In mass disasters, however, the remains are often fleshed, burned, and/or commingled. As a result, osteometric methods are difficult to apply. In such cases, radiography can be of great use during the examination process. A total of 101 (53 males and 48 females) adult humeri were radiographed using digital equipment (Technix TCA 4R PLUS). Specific measurements were taken on the radiographs and then analyzed. Multivariate discriminant function analysis was applied, and the results showed up to 89.1% classification accuracy. Single variables performed equally well for both epiphyses reaching 86.1% correct group membership. The method proposed here is successful, offering an alternative sex estimation technique applicable to the identification of deceased individuals whose remains are semi-fleshed, burned, mutilated, or otherwise unrecognizable. Specifically, this method is extremely useful when maceration of the remains is not an option.

Morphometric analysis of clavicle in nepalese population.

BACKGROUND: Determining the sex of deceased is easy when a complete skeleton is available for examination. On the whole, the bones are heavier, larger and markings of muscular attachments are more pronounced in the male than in the female. OBJECTIVE: The purpose of this study was attempted to evolve an easily applied formula to enable the assessment of sex in an unknown clavicles and to know about comparative differences between the right and left clavicles, from certain metrical parameters. METHODS: The study was an observational, cross-sectional and descriptive in nature. The present study was conducted on 257 adult clavicles out of which, 135 were of the right side and 122 of left side. The maximum length of the clavicle (in mm) was taken. RESULTS: The length of the right clavicles varies from 108 mm to 178 mm with an average of 143.21 mm ± 11.13 mm S.D. The length of the left clavicles varies from 111 mm to 181 mm with an average 145.53 mm ± 11.04 mm S.D. It has been observed that the left clavicle was longer than the right clavicle by 2.32 mm. There was no such single character which can determine the sex of all clavicles. Depending on the length alone, the sex can be decided in 13.33% male and 4.44% female right clavicles and 16.39% male and 9.83% female bones if the left clavicle is considered. CONCLUSION: The left clavicle was longer than the right clavicle. The determination of sex from the clavicle has a great medico legal significance to the toxicologists. It also helps the anthropologists in their study of evolution of mankind and migration of races.

Sex determination in mandibles in the first year of life by a quantitative approach / Determinación del sexo en mandíbulas en el primer año de vida mediante una aproximación cuantitativa

Numerous studies have shown that skeletal characteristics vary among different populations. Several authors suggest that it is possible to determine sex through the anatomical evaluation of children mandible, however there are few morphometrical studies conducted with such specimens. The purpose of this study was to analyze several mandibular dimensions and identify the ones that could be useful to perform sex differentiation in a sample of Brazilian young children. For this study we used 32 children dry mandibles of known sex, age ranging from 0 to 1 year old. The mandibles pertain to the collection of the Skull Museum of the Universidade Federal de Sao Paulo (UNIFESP). The parameters included bicondilar width, bigonial width, minimum width and height of the mandibular ramus, gonion-gnation length, height of the mandibular symphysis and transverse and anteroposterior condylar dimensions. The SPSS program was used to carry on the discriminant function analysis and the T test (p <0.05). There were no statistically significant differences that could allow identification of a specific parameter for sex determination. However, most of the dimensions were higher in male than in female, except for the minimum width of the mandibular ramus (0.2-0.16 mm) and transverse diameter of the right condyle (0.16mm). The values obtained for the anteroposterior diameter of the mandibular head were the most different between genders, although no statistically significance was found. Discriminant function analysis indicated that, despite differences, none of the evaluated parameters allow for sex classification with enough reliability. In conclusion, there is little sexual dimorphism in children's mandibles during the first year of life and anatomical analysis of this structure is not recommended as reliable quantitative approach for sex differentiation with forensic purposes.

Numerosos estudios han demostrado que las características esqueletales varían en las distintas poblaciones. Diversos autores indican que es posible la determinación del sexo en base a mandíbulas infantiles; sin embargo, existen escasos estudios morfométricos realizados en mandíbulas de niños brasileros. El propósito de este estudio fue analizar distintas dimensiones de mandíbulas y determinar aquellas de utilidad en el diagnóstico forense del sexo, en población infantil brasilera. Se utilizaron 32 mandíbulas de niños brasileros de entre 0 y 1 año de edad, de sexo conocido, pertenecientes a la colección de cráneos de la Universidade Federal de Sao Paulo (UNIFESP). Las mediciones mandibulares incluyeron ancho bicondilar, ancho bigonial, ancho mínimo y altura de la rama mandibular, longitud gonion- gnation, altura de la sínfisis mandibular y las dimensiones transversa y anteroposterior del cóndilo. Los datos obtenidos fueron sometidos al t test (p<0,05) y análisis de la función discriminante con SPSS. La mayoría de las dimensiones fueron superiores en hombres que en mujeres, con excepción del ancho mínimo de la rama mandibular (0,2-0,16 mm) y del diámetro transverso del cóndilo derecho (0,16 mm). El diámetro anteroposterior de la cabeza mandibular resultó la más dimórfica de las medidas analizadas, aunque ninguna diferencia resultó estadísticamente significativa. El análisis de la función discriminante indicó que a pesar de las diferencias, éstas no permiten clasificar de acuerdo al sexo, en base a las variables cuantitativas analizadas. En conclusión, la mandíbula de niño en el primer año de vida presenta escaso dimorfismo sexual y no se recomienda el abordaje cuantitativo para la determinación del sexo con fines forenses.

The influence of age, sex, population group, and dentition on the mandibular angle as measured on a South African sample.

The mandibular angle is measured in physical anthropological assessments of human remains to possibly assist with the determination of sex and population affinity. The purpose of this investigation was to establish how the mandibular angle changes with age and loss of teeth among the sexes in South African population groups. The angles of 653 dried adult mandibles from the Pretoria Bone Collection were measured with a mandibulometer. Males and females of both South African whites and blacks were included. To compensate for imbalances in numbers among subgroups, type IV ANOVA testing was applied. No association was found between age and angle within either of the populations, within sexes, or within dentition groups. The angle was the most obtuse in individuals without molars and with an uneven distribution of molars, and most acute in the group with an even distribution of molars on both sides. Statistically significant differences (P < 0.001) were found in the angle between the two population groups and sexes in the overall sample as well as in the subgroup with absent molar teeth (P = 0.003 for sex, males more acute angle, and P = 0.001 for population group, blacks more acute angle), although a very large overlap existed. No significant differences could be demonstrated between the sexes or populations within the subgroups with molars. We concluded that the loss of molars, especially if complete or uneven, has a considerable effect on the mandibular angle. In the assessment of human remains, the mandibular angle is not very usable in determining sex.