Sex determination from adult human humerus by discriminant function analysis

Background: Sex determination of unidentified skeletal remains from crime scenes or excavation sites is an important component in the development of the biological profile in forensics, anthropology and bioarchaeology. The purpose of this research is to determine whether sexing of unknown adult human humerus bones can be done by applying values of morphometric parameters and formulae generated by present study on adult human humerus bones of known sex and to find out the best parameters for sex determination.Methods: Various metric measurements were recorded using osteo metric board, measuring tape, non-elastic thread, sliding calipers and Vernier calipers on adult human humerus bones.Results: Sex was correctly estimated by using stepwise discriminant function analysis, for the clavicle 100% of males and 95% of females, with a total accuracy of 98.1%. Direct discriminant function analysis, correct estimated sex for the clavicle was 100% in males and 95% in females with a total accuracy of 98.1%.Conclusions: Present study exhibited better classification accuracy for multiple variables than those of single variables, the most discriminating variables in stepwise analysis are the weight, total length, transverse diameter of head, circumference of midshaft, trochlear width, capitulum width. In direct analysis, the single most useful variable was the transverse diameter of head

An evaluation of a metric method for sex estimation using the clavicle, humerus, radius, and ulna

Sex estimation is important in both forensic and bioarchaeological contexts for the construction of a biological profile, which might aid in the identification process in forensic cases or answer demographic questions in archaeological contexts. The os coxa is generally considered the best indicator of sex, given its reproductive functionality in females, although it is not always available for analysis, thus presenting a need for alternative methods of sex estimation. The present research aims to validate the previous study by Albanese (2013), which examined the use of the clavicle, humerus, radius, and ulna. Albanese (2013) applied logistic regression analysis to the osteometric data and achieved allocation accuracies between 87.4% and 97.5%. A sample size of 400, comprised of American Whites and American Blacks from the William M. Bass Donated Skeletal Collection, was utilized in the present study. The present study applies both discriminant function analysis and logistic regression analysis to a total of 20 measurements collected from the clavicle, humerus, radius, and ulna, including three variant measurements that were proposed by Albanese (2013), and a set discriminant functions and logistic regression equations were produced to classify individuals as male or female. Allocation accuracies as high as 100% were produced by the logistic regression equation that utilized all measurements. Discriminant analysis was applied to each of the bones individually, and the results indicated that the humerus exhibited the most sexual dimorphism and had the highest allocation accuracies (95.0% for males and 97.0% for females). Measurements that exhibited the greatest degree of sexual dimorphism were those representative of joint size such as the maximum diameter of the radial head, the vertical diameter of the humeral head, and the epicondylar breadth of the humerus. A set of equations were produced through discriminant function analysis, which are representative of various recovery scenarios and are meant to provide the examiner with sets of equations that might be applicable to a particular case. Because of its high allocation accuracies and its applicability to contemporary American White and Black populations, the methodology should be useful in forensic contexts within the United States. Sex estimation is important in both forensic and bioarchaeological contexts for the construction of a biological profile, which might aid in the identification process in forensic cases or answer demographic questions in archaeological contexts. The os coxa is generally considered the best indicator of sex, given its reproductive functionality in females, although it is not always available for analysis, thus presenting a need for alternative methods of sex estimation. The present research aims to validate the previous study by Albanese (2013), which examined the use of the clavicle, humerus, radius, and ulna. Albanese (2013) applied logistic regression analysis to the osteometric data and achieved allocation accuracies between 87.4% and 97.5%. A sample size of 400, comprised of American Whites and American Blacks from the William M. Bass Donated Skeletal Collection, was utilized in the present study. The present study applies both discriminant function analysis and logistic regression analysis to a total of 20 measurements collected from the clavicle, humerus, radius, and ulna, including three variant measurements that were proposed by Albanese (2013), and a set discriminant functions and logistic regression equations were produced to classify individuals as male or female. Allocation accuracies as high as 100% were produced by the logistic regression equation that utilized all measurements. Discriminant analysis was applied to each of the bones individually, and the results indicated that the humerus exhibited the most sexual dimorphism and had the highest allocation accuracies (95.0% for males and 97.0% for females). Measurements that exhibited the greatest degree of sexual dimorphism were those representative of joint size such as the maximum diameter of the radial head, the vertical diameter of the humeral head, and the epicondylar breadth of the humerus. A set of equations were produced through discriminant function analysis, which are representative of various recovery scenarios and are meant to provide the examiner with sets of equations that might be applicable to a particular case. Because of its high allocation accuracies and its applicability to contemporary American White and Black populations, the methodology should be useful in forensic contexts within the United States

Metric, nonmetric, and geometric morphometric methods of sex estimation using the distal humerus

Sex estimation is one of the most important, and arguably the first, parts of the biological profile that is estimated for purposes of human identification. This study will examine the utility of the distal humerus in sex estimation. The goal of this research is to corroborate the usefulness of the distal humerus in sex estimation and the usefulness of geometric morphometrics in sex estimation, as well as validate metric and visual methods for sex estimation using the distal humerus. Multiple methods of sex estimation are necessary because complete skeletons are rarely found, and often only fragments are discovered. Three methods of sex estimation utilizing the distal humerus are used in this study: epicondylar breadth (n=448), nonmetric traits per Rogers (1999) and Vance et al. (2011 (n=444)), and geometric morphometrics via a Microscribe digitizer and MorphoJ software (n=227). The sample was taken from the William M. Bass Donated Skeletal Collection and was primarily composed of White Americans. The male to female ratio was approximately equal. The results of the metric aspect of the study showed a classification accuracy of 88.84% with low intra-observer and inter-observer error rates. The results of the nonmetric aspect of the study showed a classification accuracy of 77% when all traits were combined with low intra-observer and high inter-observer error rates. The results of the geometric morphometric aspect of the study showed a classification accuracy of 55% for all landmarks, 57% for anterior landmarks, and 63% for posterior landmarks. The results show that not only is the epicondylar breadth a reliable and effective method of sex estimation, it is easily repeatable by other observers. The nonmetric method is useful when epicondylar breadth cannot be measured or when an observer is familiar with the method. The geometric morphometric method is not as strong as the other two methods, but with further research and modifications may become a feasible option for sex estimation using the distal humerus. The author concludes that the distal humerus is sexually dimorphic and can be used to estimate sex accurately

Assessing Size and Strength of the Clavicle for its usefulness for Sex Estimation in a British Medieval Sample.

The construction of the biological profile from human skeletal remains is the foundation of anthropological examination. However, remains may be fragmentary and the elements usually employed, such as the pelvis and skull, are not available. The clavicle has been successfully used for sex estimation in samples from Iran and Greece. In the present study the aim was to test the suitability of the measurements used in those previous studies on a British Medieval population. In addition, the project tested whether discrimination between sexes was due to size or clavicular strength. The sample consisted of 23 females and 25 males of pre-determined sex from two medieval collections: Poulton and Gloucester. Six measurements were taken using an osteometric board, sliding callipers and graduate tape. In addition, putty rings and bi-planar radiographs were made and robusticity measures calculated. The resulting variables were used in stepwise discriminant analyses. The linear measurements allowed correct sex classification in 89.6% of all individuals. This demonstrates the applicability of the clavicle for sex estimation in British populations. The most powerful discriminant factor was maximum clavicular length and the best combination of factors was maximum clavicular length and circumference. This result is similar to that obtained by other studies. To further investigate the extent of sexual dimorphism of the clavicle, the biomechanical properties of the polar second moment of area J and the ratio of maximum to minimum bending rigidity are included in the analysis. These were found to have little influence when entered into the discriminant function analysis

Metric Methods of Skeletal Sex Determination using the Arm Bones

Several studies have stated the importance of devising population-specific metric methods for sex determination. The long bones of the arm have been previously reported as having a high reliability. This paper explores the degree of sexual dimorphism in adult arm bones displayed in two Medieval British populations, one urban and one rural. The urban Gloucester population sample consists of 45 individuals (19 female and 26 male) and the rural Poulton sample of 27 individuals (13 female and 14 male) and were selected from collections housed at Liverpool John Moores University. Measurements of the proximal and distal epiphyses along with maximum length were used on the humerus, radius and ulna. These populations showed sexual dimorphism in every measurement taken. Discriminant function analysis found that all arm bones had very high discriminant accuracies in both populations reaching 91.2% (Gloucester radii) and 95.5% (Poulton radii). It was found that some of the values were significantly different between the populations supporting the necessity for population-specific metric standards

Metric Methods of Skeletal Sex Determination using the Arm Bones of Two British Medieval Populations

Several studies have stated the importance of devising population-specific metric methods for sex determination. The long bones of the arm have been previously reported as having a high reliability. This paper explores the degree of sexual dimorphism in adult arm bones displayed in two Medieval British populations, one urban and one rural. The urban Gloucester population sample consists of 45 individuals (19 female and 26 male) and the rural Poulton sample of 27 individuals (13 female and 14 male) and were selected from collections housed at Liverpool John Moores University. Measurements of the proximal and distal epiphyses along with maximum length were used on the humerus, radius and ulna. These populations showed sexual dimorphism in every measurement taken. Discriminant function analysis found that all arm bones had very high discriminant accuracies in both populations reaching 91.2% (Gloucester radii) and 95.5% (Poulton radii). It was found that some of the values were significantly different between the populations supporting the necessity for population-specific metric standards.

Sex Determination Using the Femur in an Ancient Japanese Population

Determination of sex from the femur measurements has been attempted in several populations and various studies have demonstrated the importance of population specific standards in the metric assessment of sex. The present study attempts to establish metric standards for sex determination by using femur measurements for ancient Japanese populations. Osteometric data were obtained from 151 adult skeletal remains from Jomon period, Yoshigo human skeletal collection. Eight femur measurements were taken and the data were analyzed by discriminant analysis using SPSS version 10.0. For the univariate discriminant function derived, precision of sex determination was 93% with the condyle breadth. Prediction values showed that sex differentiation could be done by femur measurements with reliability between 66.9 and 100%, with values for males higher than for females. It is suggested that discriminant formulas developed by femur measurements in this study, can be used for sex determination accurately on fragmentary skeletal remains in ancient Japanese populations

A COMPREHENSIVE CASE REPORT OF THE UNIVERSITY OF MONTANA CASE 37

In this professional paper I examine the human skeletal remains of one individual. The remains were analyzed to gain insight into the age, sex, ancestry, stature, weight, pathology, and trauma of the individual. Forensic anthropological methods were applied to UMFC 37. The remains of UMFC 37 represent a male, between the age of 40 and 60. He is likely a Caucasian. UMFC 37 is between 5 feet 6 inches and 5 feet 10 inches tall and weighs between 148 and 167 pounds

Kaelin Rapport - Histological Techniques for the Sex Determination of Skeletonized Human Remains

Determining the sex of skeletons is problematic in forensic and bio-archaeological research. Past studies demonstrate that bone cells can sometimes contain preserved sex chromosomal material in ancient samples. The sex chromosomes in skeletal remains may allow determination of sex in non-adults. The problem is explored by making 20μ thin sections stained with hematoxylin eosin. The dye highlights inactive X chromosomes (Barr Bodies) of females. The presence of the Barr Body is an indicator of female with an accuracy of greater than 99.9. This approach to identification of sex in unknown skeletons has been demonstrated with remains of individuals deceased as long as 25 years. Intact bone cells have also been observed in Neanderthal and Sauropod fossils and likely contain sex chromosomes. The degree to which bone cells preserve in archaeologically derived skeletal remains is explored here. A sample of 22 thin sections was created and examined for intact bone cells. The survivorship rate of bone cells in this sample is .12. Exposure to moisture facilitates bacterial activity and this is noted to be the single most important variable in determining the degree of preservation of histological structure. This technique has the potential of providing an accurate means of determining sex in non-adult skeletons. This will greatly assist forensic investigators and open new research trajectories into life-ways and life experiences in past populations.https://epublications.marquette.edu/mcnair_2014/1008/thumbnail.jp

Sex estimation standards for medieval and contemporary Croats

AimTo develop discriminant functions for sex estimation on medieval Croatian population and test their application on contemporary Croatian population. MethodsFrom a total of 519 skeletons, we chose 84 adult excellently preserved skeletons free of antemortem and postmortem changes and took all standard measurements. Sex was estimated/determined using standard anthropological procedures and ancient DNA (amelogenin analysis) where pelvis was insufficiently preserved or where sex morphological indicators were not consistent. We explored which measurements showed sexual dimorphism and used them for developing univariate and multivariate discriminant functions for sex estimation. We included only those functions that reached accuracy rate 80%. We tested the applicability of developed functions on modern Croatian sample (n=37). ResultsFrom 69 standard skeletal measurements used in this study, 56 of them showed statistically significant sexual dimorphism (74.7%). We developed five univariate discriminant functions with classification rate 80.6%-85.2% and seven multivariate discriminant functions with an accuracy rate of 81.8%-93.0%. When tested on the modern population functions showed classification rates 74.1%-100%, and ten of them reached aimed accuracy rate. Females showed higher classification rates in the medieval populations, whereas males were better classified in the modern populations. ConclusionDeveloped discriminant functions are sufficiently accurate for reliable sex estimation in both medieval Croatian population and modern Croatian samples and may be used in forensic settings. The methodological issues that emerged regarding the importance of considering external factors in development and application of discriminant functions for sex estimation should be further explored