M. Yaşar İşcan

Age Estimation from the Rib by Phase Analysis: White Males

The determination of age at death is an important part of physical and forensic anthropology. Techniques now in use vary from direct observation of a bone to microscopic examination of a given segment. This study introduces the sternal end of the rib as a new site for age estimation by direct observation. The sample consisted of 118 white male ribs of verified age, sex, and race. The ribs were assigned to one of nine phases (0 through 8) based on changes noted at the costochondral junction. These included the formation of a pit, its depth and shape, configuration of the walls and rim surrounding it, and the overall texture and quality of the bone. Statistical analysis indicated that these changes were age related. It was further revealed that metamorphosis was most rapid and uniform from the mean age of 17 to 28 years (Phases 1 through 4). The rib morphology was more varied after age 39 (Phase 5) resulting in a wider range for the predicted age. Our study concluded that the sternal rib end may yield a similar degree of accuracy to the pubic symphysis and perhaps better than that for cranial sutural closure. Our technique also enables the forensic scientist to use the rib for corroboration with age estimations obtained by traditional methods.

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.

Sex determination from the femur and tibia in South African whites

With the current high incidence of violent crimes in South Africa, it has become very important to be able to determine the sex of individuals from their skeletal remains. The aim of this study is to provide standards usable for this purpose, to be used on the contemporary South African white population. Very little skeletal data is available for this group. Osteometric information was obtained from 56 male and 50 female individuals from cadaver collections. Six femoral and seven tibial measurements were taken, and subjected to SPSS discriminant function analysis. The distal breadths from both the femur and tibia provided the best discrimination. Formulae were developed for a number of combinations of measurements, which can be used to determine the sex on fragmentary remains. Average accuracies ranged from 86% to 91%, with female accuracies slightly higher than those of the males. The results of this study compares well with others, e.g., those from American whites.

Estimation of stature from body parts

Anthropometric technique commonly used by anthropologists and adopted by medical scientists has been employed to estimate body size for over a hundred years. With the increasing frequency of mass disasters, the identification of an isolated lower extremity and the stature of the person it belonged to has created problems for the investigation of the identity of some of the victims. In spite of a need for such a study, there is a lack of systematic studies to identify fragmented and dismembered human remains. The purpose of the paper is to analyze anthropometric relationships between dimensions of the lower extremity and body height. Analysis is based on a sample of middle class male (N=203) and female (N=108) adult Turks residing in Istanbul. The participants are mostly students and staff members of a medical school, and military personnel. Measurements taken are stature, trochanteric height, thigh length, lower leg length, leg length, and foot height, breadth, and length. Of the five variables entered into the regression analysis, all but foot breadth participate in the analysis with leg length as the first and followed by thigh and foot lengths, and finally foot height in males (R(2)). There were also individually calculated formulae for some of these measurements which provided smaller R(2)-values. Students t-test to assess if there was any intraobserver error in measurements take by individual anthropometrist did not show such any statistically significant difference. In conclusion, the study suggested that estimation of a living height can be made possible using various dimensions of the lower extremity. One must consider differences between populations in order to apply functions as such to others.

Sexual dimorphism in the humerus : A comparative analysis of Chinese, Japanese and Thais

Determination of sex from the skeleton is vital to medicolegal investigations. There is no longer any question that populations differ in size and proportions and these differences affect the metric assessment of sex. The extent of variation in sexual dimorphism among Asian Mongoloids within and between regions has not been quantified by discriminant function analysis, nor have standards for most groups been introduced for the humerus. Therefore, the purpose of this research is to establish metric standards for sex determination from the humerus of Chinese, Japanese and Thais, as well as to compare size and sexual dimorphism in these Asian Mongoloid populations. The database for this study consisted of documented skeletal samples from China (N = 87), Japan (N = 90), and Thailand (N = 104). Six standard dimensions, including maximum length, vertical head diameter, minimum midshaft diameter, maximum midshaft diameter, midshaft circumference, and epicondylar breadth were taken and subjected to stepwise and direct discriminant function analysis. Of dimensions selected by the stepwise function, vertical head diameter and epicondylar breadth were the only elements common to all three groups. Overall, mean accuracies were highest using formulae produced by the stepwise procedure and ranged from 86.8% in the Chinese to 92.4% in the Japanese to 97.1% in the Thais. Group comparisons also revealed that while the Chinese had the largest measurements, they were the least dimorphic. The reverse was true for the Thais and the Japanese were intermediate on both counts. In cross validation tests, classification accuracy decreased in all cases where a formula from one group was applied to another. It was therefore concluded even though all individuals were Asian Mongoloids, these regionally diverse populations exhibited significant metric differences that affect sex determination from the skeleton. These findings confirm those of previous studies that there is a need for group specific metric standards of assessment.

Metric and Comparative Analysis of Sexual Dimorphism in the Thai Femur

Identification of sex from the skeleton is an important demographic assessment in medicolegal investigations. Studies have demonstrated that populations differ from each other in size and proportions and that these differences can affect the metric assessment of sex. It is therefore vital to determine if population differences are great enough to necessitate group-specific standards. To date, there have been no attempts to create standards of assessment for modern Thais. Therefore the purpose of this research is to establish standards from which to determine sex from the femur using a new skeletal collection housed at the Chiang Mai University Department of Anatomy. The sample is composed of 104 individuals (70 males, 34 females). Six standard osteometric dimensions including maximum length, maximum head diameter, midshaft circumference, midshaft anterior-posterior and transverse diameters, and bicondylar breadth were measured and analyzed by stepwise discriminant function statistics. To understand population differences, formulas derived from Chinese, South African whites and American whites and blacks using the same method and variables were tested on the Thai sample. Results indicated that maximum head diameter and bicondylar breadth are the optimal combination for sex diagnosis and yielded 94.2% accuracy. Direct analysis using predetermined single or multiple variables also revealed bicondylar breadth as the best single dimension (93.3%). In cross-tests on the Thais, the Chinese formula gave the most favorable outcome with unsatisfactory results for all other groups. The present research confirms that sexual dimorphism is better reflected in breadth dimensions than in bone length. Comparisons showed that Thais are very different metrically from whites and blacks, and although they most resemble the Chinese, these two groups are not identical. These findings underscore the need for population-specific formulas for identification of sex from the skeleton.

Facial soft-tissue thicknesses in the adult male Zulu

The morphometric method of forensic facial reconstruction rests heavily on the use of facial soft tissue depth measurements. In reconstructing the Negroid face, much use has been made of the tables of soft tissue thickness of American Negroid cadavers. However, the genetic complexities of American blacks are well known. In addition it is felt that measurements made on the living are of more value than those made on the dead. In view of this it was decided to set up a table of norms for facial soft tissue depths of the living Zulu, an African Negroid who has remained relatively free from genetic admixture with other populations. The tightly controlled sample consisted of 55 healthy male Zulus, aged 20 to 35. Tissue depths at established landmarks were measured from lateral and oblique cephalometric radiographs. These were then combined with ultrasonic readings at other landmarks on the subjects face to yield a comprehensive set of tissue depth data. This paper presents a set of average facial soft tissue depth measurements from the Zulu face that results in the development of a new profile. It also provides a method for linking two systems of measurement.

Determination of Age from the Sternal Rib in White Females: A Test of the Phase Method

Sex differences in both the rate and pattern of aging in the sternal extremity of the rib necessitated the development of separate standards of age determination for males and females. A test of the male phase technique has already demonstrated its reliability and soundness. The present study was carried out to evaluate the female phase standards. A sample of 10 test ribs including 2 control specimens, was judged by 28 volunteers representing several levels of education and experience in the forensic and anthropological sciences. As in the male test, the judges were asked to assign each unknown rib to an age phase by comparing it with photographs of prototype specimens from the original study. Analysis of the results revealed minimal interobserver error between the doctoral and predoctoral groups, and no discernible association between morphological variation in the rib and antemortem history. Furthermore, rib assignment for both groups of judges averaged well within 1 phase of the ideal phase in which the specimen would have been placed based solely on chronological age.

Sexual dimorphism in the Chinese femur

In the last decade, there has been renewed interest in contemporary and ancient Chinese skeletal populations. The purpose of this research is the osteometric assessment of sexual dimorphism in recent mainland Chinese cemetery populations and the development of discriminant function standards to determine sex from the femur. The sample for this project was composed of 87 adult skeletons from cemeteries in Chang Chun City (Liaoning) and Qingdao (Shandong). A total of six femoral measurements was taken and subjected to SPSS discriminant function analysis. Three dimensions were selected by the stepwise analysis in the following order: distal epiphyseal breadth, maximum length, and anteroposterior diameter of the midshaft. This function produced 92.3% classification accuracy. Direct analysis revealed that distal epiphyseal breadth alone provided an even better separation (94.9%). The remaining functions were less discriminating. In conclusion, distal epiphyseal breadth is the most dimorphic part of the Chinese femur. This contrasts with earlier findings on American Whites and Blacks in which head diameter is the most dimorphic. This and other significant differences underscore the necessity of obtaining population-specific values for metric analysis of sex. These findings also support previous studies indicating that linear dimensions such as length are often less discriminating than breadth and circumference measurements in long bones. Finally, the fact that maximum dimorphism was found at a major weight-bearing joint suggests that the size differentials between Chinese males and females may be in large part functional in nature, perhaps arising from sex-specific physical activities.

Osteometric Analysis of Sexual Dimorphism in the Sternal End of the Rib

Although there have been a number of radiological studies of the entire anterior thorax, no attempt has been made to establish a method of sex determination based on direct metrical analysis of an isolated rib. The present study attempts to determine sex from the sternal end of the fourth rib. The sample (144 males, 86 females) was obtained from individuals of known age, sex, and race autopsied at a medical examiners office. Three measurements (height, width, and sternal articular pit depth) were taken from each bone. The sample was divided into three groups: young, old, and the combined total and analyzed by means of stepwise discriminant function statistics. It was found that the accuracy of sex determination varied from 82% in the young and 89% in the old groups to 83% for the combined group. However, when a discriminant function formula developed for a different age group was used the accuracy of correct assessment diminished considerably. It was, therefore, concluded that sexual dimorphism can be detected by metrical analysis from the teens to the 70s and this dimorphism increases with age.