Mubarak Ariyo Bidmos

The History and Composition of the Raymond A. Dart Collection of Human Skeletons at the University of the Witwatersrand, Johannesburg, South Africa

The Raymond A. Dart Collection of Human Skeletons (Dart Collection) is housed in the School of Anatomical Sciences at the University of the Witwatersrand, Johannesburg, South Africa, and comprises one of the largest documented cadaver-derived human skeletal assemblages in the world. This collection originated in the early 1920s as a result of the efforts of Raymond Dart and continues to grow. The skeletons included represent varied indigenous and immigrant populations from southern Africa, Europe and Asia. This contribution documents the history of the collection and provides an updated inventory and demographic assessment of this valuable research collection. According to a recent inventory the Dart Collection currently comprises 2,605 skeletons representing individuals from regional SA African (76%), White (15%), Coloured (4%) and Indian (0.3%) populations. A large proportion of the skeletons (71%) represent males. The recorded ages at death range from the first year to over 100 years of age, but the majority of individuals died between the ages of 20 and 70. The Dart Collection has been affected by collection procedures based on availability. All of the cadavers collected before 1958, and large proportions subsequently, were derived from unclaimed bodies in regional South African hospitals. Some details of documentation (age at death, population group) are estimates and some aspects of the collection demographics (sex ratios) do not closely reflect any living South African population. Our inventory and analysis of the Dart Collection is aimed to assist researchers planning research on the materials from this collection.

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%).

Anatomical variations in the human testicular blood vessels.

The testis is an important organ upon which the survival of the human species depends. The testicular arteries and veins play major roles in the thermo-regulation that is essential for the efficient functioning of this organ. However, very little is found in the literature about the veins and their anatomical variations. Therefore the testicular veins and arteries in 150 dissection room cadavers at the University of the Witwatersrand, Johannesburg and University of Zimbabwe, Harare were examined for anatomical variations from the usual descriptions in textbooks of Anatomy. Variations were found more frequently in the testicular veins than in the accompanying arteries. The variations, which were more common on the left side, were seen in 32 (21.3%) of the cadavers. In 6 (18.8%) of these cases, the variations were present bilaterally. The veins were either completely or partially duplicated, with or without beading. The duplicated veins terminated in the corresponding renal veins either separately or after combining into one vein. In two cases, the right testicular vein terminated in the right renal vein, rather than in the inferior vena cava. Anatomical variations of the testicular artery were present in 4.7% of cases and were associated with their origin, which were either from unusually high levels of the abdominal aorta or from the renal artery.

An assessment of sex using the skull of black South Africans by discriminant function analysis.

The derivation of discriminant function equations for skeletal elements of South African populations continues to be an area of interest to both forensic anthropologists and skeletal biologists alike. The skull of black South Africans has previously been subjected to discriminant function analysis, using four measurements and two indices; however, no equations were derived to address the issue of sex determination. Recently Franklin, Freedman and Milne [2005. Sexual dimorphism and discriminant function sexing in indigenous South African crania. HOMO J. Comp. Hum. Biol. 55, 213-228] used the crania of black South Africans, in a three-dimensional approach, with eight linear measurements to investigate sex determination. This study, although valuable, requires the use of highly technical and expensive morphometric equipment that renders it less feasible in South Africa. In response to this, our study uses traditional anthropometric measurements and equipment to address the question of sex determination from the crania and mandible of blacks. One hundred and twenty non-pathological skulls were randomly selected from the Raymond Dart Collection of Human Skeletons, equally distributed by sex and belonging to individuals whose age at death ranges between 25 and 70 years. Fourteen cranial and six mandibular measurements were subjected to discriminant function analyses and discriminant function equations were derived for sex determination. Average accuracies ranged between 80% and 85% and were on par with that obtained in previous studies. Our study shows that traditional methods provide average accuracies that are comparable to those obtained using more complex techniques.

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.

Sex determination from the talus of South african whites by discriminant function analysis.

The field of forensic anthropology involves the building of an antemortem profile of an individual from skeletal remains. This includes sex and race determination and age and stature estimation. Since most bones that are conventionally used for sex determination are often recovered either in a fragmented or incomplete state, it has become necessary to use denser bones that are often recovered intact, eg, the patella, calcaneus, and talus. Thus the aim of this study is to assess the sex-determining ability of each of the measurements of the talus and derive discriminant function equations for sex determination in the South African white population. Sixty male and 60 female tali of South African whites obtained from the Raymond A. Dart Collection of Human Skeletons were used. Nine measurements were taken on each talus. Descriptive statistics and discriminant function analysis were performed on the acquired data. The basic statistics showed that all measurements were sexually dimorphic. Univariate, stepwise, and direct discriminant function equations were generated for use in sex determination. The level of average accuracy of sex classification was 80% to 82% for the univariate method, 85% to 88% for the stepwise method, and 81% to 86% for the direct method. It is concluded that the talus of South African whites is useful for sex determination.

The skull and humerus in the determination of sex: Reliability of discriminant function equations §

Sex determination plays a crucial role in the identification of human remains as it narrows the possibility for identification by 50%. The purpose of this study is to test the validity of five discriminant function equations, with accuracies of 80% and higher, that have been derived by Steyn and Işcan [M. Steyn, M.Y. Işcan, Sexual dimorphism in the crania and mandibles of South African Whites, Forensic Sci. Int. 98 (1998) 9-16; M. Steyn, M.Y. Işcan, Osteometric variation in the humerus: sexual dimorphism in South Africans, Forensic Sci. Int. 106 (1999) 77-85] for the skull and humerus of South Africans of European Descent (SAED). These equations were tested on different regional populations of SAED within South Africa. While the validity of some of the discriminant functions has been assessed by the authors who derived them, no other previous independent study has been carried out to assess the reliability of these equations. In addition, these equations have not been tested on skeletons located outside the Gauteng province. The study sample consisted of 230 skulls and 264 humeri of SAED obtained from four South African skeletal collections: Raymond A. Dart Collection of Human Skeletons (Johannesburg); Pretoria Bone Collection; Cape Town Skeletal Collection; and the Osteology Archive Student Collection (Stellenbosch). A total of 14 measurements (12 cranial and 2 humeral) were taken on these skeletal elements. The observed accuracies from the present study (72.0-95.5%), with the exception of one samples accuracy, compared well with the original classification rates (80.2-92.5%) for most of the functions thereby confirming the validity of the discriminant function equations for sex determination for the skull and humerus of SAED, for SAED in all regions of South Africa.

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.

Stature Reconstruction Using Fragmentary Femora in South Africans of European Descent

Abstract:  It is well documented that the intact femur has the highest correlation with stature and as such has been widely used in the derivation of regression equations for stature estimation. As intact femur is not always present for analyses in forensic cases, it has become necessary to derive regression equations for the estimation of stature from fragments of this bone. Few studies have presented regression equations for stature estimation from fragments of the femur. Because these equations are population specific, it was the aim of this study to derive similar equations for estimation of stature and maximum length of femur from measurements of the femur of South Africans of European descent. A sample of 50 male and 50 female complete skeletons were obtained from the Raymond A. Dart Collection of Human Skeletons. Total skeletal height for each of the skeletons was calculated using the Fully’s method. Six variables were measured on each femur which included the vertical neck diameter, upper breadth of femur, epicondylar breadth, bicondylar breadth, lateral condyle length, and medial condyle length. Regression equations for the estimation of stature are presented. The range of standard error of estimate for these equations (3.71–5.31) was slightly higher than those obtained for intact long bones (2.13–3.79). It is therefore suggested that in the absence of intact femur, regression equations derived from the present study can provide a reliable estimate of adult stature.

Estimation of stature using fragmentary femora in indigenous South Africans

Intact long bones of the upper and lower extremities have been used in the derivation of regression equations for the estimation of stature in different population groups. These bones are sometimes presented to forensic anthropologists in different states of fragmentation thereby making the derived equations unusable. This has necessitated the need to assess the usefulness of measurements of fragments of long bones (e.g., femur) in the estimation of stature. While few studies have reported such equations, which are population and sex specific, it was the aim of this study to derive equations based on measurements of commonly preserved fragments of the femur for the indigenous South African population group. A total of 100 complete skeletons, equally distributed by sex, were obtained from the Raymond A. Dart collection of human skeletons. Stature was estimated for each of the skeleton using the Fully’s method (Fully in Ann Med Leg 35:266–273, 1956). Regression equation for the estimation of stature and maximum length of the femur were derived from six measurements of the femur. The standard error of estimate for regression equations for stature estimation (3.72–4.38) was slightly higher than that presented for intact femur. This study confirms the usefulness of fragments of the femur of indigenous South Africans in the estimation of stature.