Discriminant function sexing of fragmentary femur of South African blacks

When fragmentary and incomplete bones are all that are available to the forensic anthropologist for use in sex determination, non-metric and metric sex discriminating parameters that have been derived from complete bones may be of little use. In such circumstances, sex discriminating metric methods that are of specific application to fragmentary bones will be more useful. Since such studies have not been systematically carried out in bones of South African blacks, the aim of this study was to begin to provide such data. Two hundred and twenty left femurs of black South Africans were obtained from the Raymond A. Dart Collection of African Skeleton, School of Anatomical Sciences, University of the Witwatersrand, South Africa. Five variables from the upper end of the femur and three variables from the lower end of the femur were measured and subjected to univariate and multivariate discriminant function analyses. The vertical head diameter and the medial condylar length were most successful in sex identification from the upper and lower ends of the femur respectively. The combined variables were more useful than the use of variables individually. Discriminant function score equations were derived for individual and combined variables from the upper and lower ends of the femur of the South African blacks.     

Sex determination from the radius and ulna in a modern South African sample

With a large number of unidentified skeletal remains found in South Africa, the development of population specific osteometric standards is imperative. Forensic anthropologists need to have access to a variety of techniques to establish accurate demographic profiles from complete, fragmentary and/or commingled remains. No research has been done on the forearm of African samples, even though these bones have been shown to exhibit sexual dimorphism. The purpose of this paper is to develop discriminant function formulae to determine sex from the radius and ulna in a South African population. The sample consisted of 200 male and 200 female skeletons from the Pretoria Bone (University of Pretoria) and Raymond A. Dart (Witwatersrand University) collections. Sixteen standard anthropometric measurements were taken from the radius (9) and ulna (7) and subjected to stepwise and direct discriminant function analysis. Distal breadth, minimum mid-shaft diameter and maximum head diameter were the best discriminators of sex for the radius, while minimum mid-shaft diameter and olecranon breadth were selected for the ulna. Classification accuracy for the forearm ranged from 76 to 86%. The radius and ulna can be considered moderate discriminators for determining sex in a South African group. However, it is advised that these formulae are used in conjunction with additional methods to determine sex.     

Sexual dimorphism of the calcaneus of South African blacks

Forensic anthropology is a rapidly growing field in South Africa and skeletal biologists are often called upon by the police to assist in personal identification from skeletal remains, which are recovered in suspected cases of homicide and suicide and in mass disaster. Measurements of the calcaneus have been shown to be sexually dimorphic in South African whites. Since the validity of discriminant function equations in sex determination is population specific, the aim of the present study was to derive similar equations for the calcanei of the South African blacks. The bones that were used in this study were obtained from the Raymond A. Dart Collection of Human Skeletons, School of Anatomical Sciences, University of the Witwatersrand, Johannesburg. One hundred and sixteen (116) intact and non-pathological calcanei, consisting of 58 males and 58 females and belonging to individuals whose age at death ranged between 22 and 75 years, were selected by the simple random sampling technique. The measured variables included the maximum length, the load arm length, the dorsal articular facet length, the body height, the maximum height, the cuboidal facet height, the middle breadth, the dorsal articular facet breadth and the maximum breadth. Discriminant function analyses were done using the Statistical Product and Service Solutions (SPSS) program. All measured parameters of the calcaneus showed significant sexual differences. Length measurements were found to be the most sexually dimorphic. Combinations of variables provided better estimate of sex (79%-86%) than individual variables (64%-79%).     

Sexual dimorphism in the crania and mandibles of South African whites

Numerous studies have clearly demonstrated that skeletal characteristics vary by population. To date, there are no metric cranial criteria for South African whites. Therefore, the purpose of this study is to establish population specific standards for sex determination from the skull. A total of 12 standard cranial and five mandibular measurements were taken from 44 male and 47 female skeletons of known sex and race from the Pretoria and Dart collections. These were subjected to SPSS discriminant function analysis. Bizygomatic breadth was the most dimorphic dimension. Five functions were developed from the complete cranium, vault, face, mandible and bizygomatic breadth. Dimensions from the complete cranium provided the best accuracy. In the mandible, bigonial breadth was the most dimorphic of the measurements taken. Average accuracies ranged from 80% (bizygomatic breadth alone) to 86% (cranium). These accuracies are similar to those obtained by researchers on other groups (e.g., 84% in Japanese crania and about 86% in American whites and blacks). Diagnostic accuracy, however, is lower than that obtained from the South African femur and tibia.     

Discriminant function sexing of the calcaneus of the South African whites

The skull and some postcranial elements, such as the humerus, femur, and tibia, have been used in their intact states for sex determination in forensic and archaeological cases. But, in practice, these bones are often recovered in fragmented states, which render them unsuitable for use in sex determination. The calcaneus is a compact bone that is able to withstand high tensile forces. Some of its parameters have been used for sex determination in American whites and blacks (1) and Italians (2). This bone has not been used for sex determination in the South African white population. Therefore, the aim of this study was to assess the degree of sexual dimorphism of the calcaneus of the South African white population sample, derive discriminant function score equations for use in sex determination, and determine the level of accuracy of its sex-determining ability. Nine parameters were measured on each pair of 53 male and 60 female calcanei of known South African white skeletons, obtained by a random sampling technique from the Raymond A. Dart Collection of Human Skeletons, School of Anatomical Sciences, University of the Witwatersrand, Johannesburg. Basic statistic and discriminant function analysis was performed on the acquired data. The basic statistics showed that all measured parameters were sexually dimorphic. Discriminant function score equations were generated for use in sex determination. The average accuracy of sex classification ranged from 73 to 86% for the univariate method, 81 to 91% for the stepwise method, and 82 to 92% for the direct method. It is concluded that the calcaneus is useful for sex determination in the South African white population.     

Discriminating sex in South African blacks using patella dimensions

For many years, sex determination has been carried out on skeletal remains to identify individuals in forensic cases and to assess populations in archaeological cases. Since it has been shown that not all bones are found in a forensic case, discriminant function equations should be derived for all bones of the body to assist in sex determination. Numerous studies have shown the usefulness of bones of the lower extremity (e.g. femur, tibia) in sex determination using discriminant function analysis, but the use of patella measurements has not been extensively investigated for this purpose. It is therefore the aim of this study to derive discriminant function equations for sex determination from measurements of the patella of South African blacks as represented in the Raymond A. Dart Collection of Human Skeletons. A total sample of 120 (60 male, 60 female) patellae were measured using six measurements. The Statistical Product and Service Solutions (SPSS) program was used to derive the equations. Stepwise and direct analyses were performed with the highest rate of classification of 85% thereby making the patella useful for sex determination. Thus, the proposed equations derived from this study should be used with caution and only on the South African black population group.     

Tooth mineralization standards for blacks and whites from the middle southern United States

Normative standards are provided for permanent tooth mineralization stages for blacks and whites of the middle southern United States. The data cover tooth development from 3.5 to 13 years of age. Females develop more rapidly than males, and blacks are nearly twice as sexually dimorphic (7.2%) as whites (3.7%). Within each sex, blacks achieve mineralization stages significantly earlier, by about 5%, than whites. This complements earlier findings that teeth erupt at appreciably earlier mean ages in blacks.     

An assessment of the accuracy of discriminant function equations for sex determination of the femur and tibia from a South African population

The purpose of this study is to test the accuracy of seven discriminant function equations that have been derived by Steyn and Is?an for sex determination using measurements of the femur and tibia of South Africans of European descent (SAED). While the validity of some of the discriminant functions has been assessed by the authors who derived them, no previous independent study has been carried out to assess the accuracy of these equations. These equations have not been tested on skeletons located outside of the Gauteng province. A suite of measurements were taken on 272 femora and 256 tibiae obtained from four South African skeletal collections. The validity of each of the previously published equations for the femur was confirmed. However, two functions of the tibia showed low accuracy rates, most likely due to difficulties in recording the distal epiphyseal breadth measurement, and thus were found to be poor assessors of sex.     

Sex determination of Chinese femur by discriminant function

The objective of this study was to provide a method of sex determination for Chinese femur, especially for fragmentary remains. Statistical analysis of 17 measurements based on 141 northeastern Chinese femora shows that all measurements have significant sex differences. Sex determination by the midpoint method of a single measurement can obtain an average accuracy of 76.8%. The results indicate that of all dimensions the maximum head diameter is the best discriminator of sex. It alone can determine the sex of a femur with 85.1% accuracy. The results also show that maximum head diameter, transverse head diameter, epicondylar breadth, upper breadth, and medial condylar length have higher sexual dimorphisms than the dimensions of length. According to the result to stepwise discriminant analysis and the need for sexing fragmentary remains, 22 discriminant functions composed of various combinations of variables were calculated which can determine the sex of the femur correctly 82.3 to 87.2%. The methods of sex determination provided by this paper can be used to sex poorly preserved femora.     

中国南方汉族人残碎股骨上端的性别判定

目的建立中国南方地区汉族人残碎股骨上端性别判别方法。方法对国内南方九省市的已知确切性别的100具股骨进行研究，测量股骨上端的7项指标，应用SPSS统计软件对数据进行分析，建立性别判别方程。结果7项指标中6项指标存在显著的性别差异，建立全指标及单指标的性别判别方程，判别率在59．6％～92．9％。结论建立的性别判别方程可以用于法医学实践。     

Sex determination from the distal part of the femur in a French contemporary population

Until now, determining the sex of a recently deceased individual using the measurement of the bicondylar breadth of the femur (also known as condylar width, epicondylar breadth and distal epiphyseal breadth) raised some concerns as to accuracy because no sample of contemporary French subjects was available. In this study, a sample of 88 female and male femurs taken from recently deceased elderly French people was studied. The bones were collected from subjects who had donated their bodies to the Medical School of Nice. The mean value of the male bicondylar breadth was found to be greater than that of females (84.3mm versus 74.8mm), confirming the sexual dimorphism of this parameter. Furthermore, the results showed a 95.4% accuracy rate for sexing individuals. To date, in the French population, as in some other samples, epicondylar breadth is the single most accurate measurement of sex determination, ahead even of head diameter. A discriminant function is presented to allow sex determination from remains of the distal femur. With regard to the data available in the literature, sexual dimorphism is probably the result of both genetic and environmental factors. The comparison of our results with those of other populations shows that there are inter-population variations of the bicondylar breadth, and also intra-population variations that account for the differences in the accuracy rate of this variable for the purposes of sex determination. These findings underscore the need to re-evaluate bone measurements within various contemporary populations.     

Sex determination with the head of the radius

Analysis of a sample of 1108 radii corresponding to 567 black and white North Americans in the Terry Collection at the Smithsonian Institution demonstrates that the diameter of the radial head is an accurate sex discriminator for human remains. A simple "radial-head method" of sex determination consists of measuring the maximum and minimum diameters of the head and comparing such measurements with the test cutoff points. The subject is female when the maximum radial head diameter (either left or right) is less than or equal to 21 mm, and male when the maximum diameter (either left or right) is greater than or equal to 24 mm. The same decisions apply to the minimum diameters of 20 mm or less and 23 mm or more, respectively. When the maximum diameter is 23 mm or the minimum is 22 mm, the subject is more likely male; when the maximum diameter is 22 mm or the minimum is 21 mm, the subject is more likely female. The sample frequency of any one of these latter diameters is never more than 16%. Cross-validation of the method with a sample of 50 pairs of radii of the Terry Collection, different from the original specimens, resulted in 92% sexing accuracy when using the left radius singly, 94% accuracy when using the right radius singly, and 96% accuracy when using both radii jointly.     

Further evidence to show population specificity of discriminant function equations for sex determination using the talus of South African blacks

Several studies have shown that osteometric differences exist between different population groups. Thus, discriminant function equations derived for the determination of sex from skeletal elements are population specific. In a previous study, the authors derived such equations from nine measurements of the talus of South African whites with high levels of average accuracies. The validity of some of the equations was tested on data collected from a South African black sample that consisted of 120 tali, equally distributed by sex, derived from the Raymond A. Dart Collection of Human Skeletons. The average accuracies dropped significantly. This necessitated the derivation of new equations for the South African black population and the average accuracies obtained ranged between 80% and 89%. The validity of the equations derived from the present study was tested using the leave-one-out classification and two independent samples (1 and 2). The applicability of the equations with very high classification rate from the present study was tested on Independent sample 1 of 10 white tali with poor results. The result of the validity of these equations on an Independent sample 2 of 10 black tali revealed acceptably high average accuracies in correct classification thereby supporting earlier observations on population specificity of discriminant function equations.     

头颅CT片性别的识别

目的 通过头颅CT片研究性别识别的方法.方法 在头颅CT片测量头颅多项指标,应用各个指标进行二分类logistic回归分析建立性别判定方程. 结果应用颧弓间距指标可以建立一元方程:Z=-69.051 0.521X1,p=1/1 e-z.应用多项指标可以建立多元方程:Z=-115.873 0.585X1 0.119X4 0.254X7 0.229X8 0.101X6,P=1/1 e-z.结论 根据头颅CT片进行性别判定时,最好是测量多项指标.在指标不全时,就只需测量颧弓间距,也可以有较好的判别效果.     

Changing patterns of income among blacks and whites before and after executive order 11246

Some suggest that affirmative action has contributed to the widening gap between better-off and worse-off blacks. Analyses of census data challenge the claim.     

Sex determination from the talus and calcaneus measurements

Several studies have demonstrated that discriminant function equations used to determine the sex of a skeleton are population-specific. The purpose of the present research was to develop discriminant function equations for sex determination on the basis of 18 variables on the right and left talus and calcaneus in a modern northern Italian sample. The sample consisted of 118 skeletons (62 males and 56 females) from the Frassetto Collection (University of Bologna). The ages of the individuals ranged from 19 to 70 years. The results indicated that metric traits of the talus (in particular) and calcaneus are good indicators of sexual dimorphism. The percentage of correct classification was high (87.9-95.7%). In view of the differences among current Italian populations, we tested the validity of the discriminant function equations in an independent sample of individuals of different origin (northern and southern Italy). The accuracy of classification was high only for the northern Italians. Most southern Italian males were misclassified as females, confirming the population-specificity of discriminant function equations.