Mehmet Yaşar İşcan

Superimposition and reconstruction in forensic facial identification: a survey

Forensic facial reconstruction, is the reproduction of the lost or unknown facial features of an individual, for the purposes of recognition and identification. It is generally accepted that facial reconstruction can be divided into four categories: (1) replacing and repositioning damaged or distorted soft tissues onto a skull; (2) the use of photographic transparencies and drawings in an identikit-type system; (3) the technique of graphic, photographic or video superimposition; (4) plastic or three-dimensional reconstruction of a face over a skull, using modelling clay. This paper sets out to review work done on both superimposition and plastic reconstruction, however, the authors believe that only the latter category can correctly be termed facial reconstruction. The survey is divided according to work done through anthropological evaluation of the skull, clinical examination and dissection of the soft tissues, as well as methods of measuring soft tissue thicknesses using tissue puncture, ultrasound, cephalometric radiography and magnetic resonance imaging. In addition, a method of the combined use of ultrasound and radiography to collect a wider range of facial soft tissue depths and a method of producing skull and face profiles are outlined.

Racial Variation in the Sternal Extremity of the Rib and Its Effect on Age Determination

Most research on the aging process in the skeleton has not considered or elaborated differences that may exist between the races. Thus, techniques developed for the estimation of age assume that the racial background of the standards is compatible with the specimens to be assessed. However, racial differences in areas such as skeletal growth and bone density have been reported, along with specific variations in the aging process, in the ribs of disparate populations. The present investigation examines metamorphosis in the sternal ribs of American blacks (N = 53 males, N = 20 females), and tests the application of age estimation standards developed by the authors from a white population. All specimens were obtained from medical examiners cases of known age, sex, and race. Although the sample was limited in both quantity and age range, analysis of the data revealed racial differences in both rate and pattern of metamorphosis. Statistical analysis showed that the calculated mean age per phase for black ribs was nearly identical to whites in Phases 1 through 4 or until the mean age of 28 years. By the early 30s, differences in morphology and their chronological association with the aging process became apparent and increased with age in both sexes. Blacks were consistently overaged from 3 to 10 years in Phases 5 through 7. Therefore, it was concluded that biological differences between these populations do exist and can affect age estimation from the rib. Social factors may also be involved, but they cannot be demonstrated from the available data. While the degree of interracial variation does not require completely new standards, the authors have suggested specific modifications of the white standards for use on black specimens.

Sex Determination from the Tibia: Standards for Contemporary Japan

It is vital that skeletal biologists and forensic anthropologists observe populations over time so that changes can be detected and monitored. The purpose of this study is to determine if temporal changes are manifest in the skeleton and, if so, develop appropriate standards to determine sex from the tibia in the contemporary inhabitants of Japan. Osteometric data were obtained from 84 recent Japanese skeletons located at Jikei Medical University, Tokyo. The collection was assembled from the anatomy dissecting room between 1960-1970. With a mean age of about 56 years for males and 51 for females, this sample represents individuals who lived through WWII. Seven tibial measurements were taken and subjected to SPSS-X discriminant function analysis. Results indicated that proximal and distal breadth measurements were selected by the stepwise procedure as the most discriminating. In addition, a number of combinations of measurements were used to develop formulae that would be suitable for fragmentary bones. Average prediction accuracy ranged from 80% from minimum shaft circumference to 89% with proximal epiphyseal breadth. Classification accuracy was higher in males (96%) than in females (79%). Compared with earlier studies of the Japanese, Jikei tibiae are longer, especially in females and thus exhibit less sexual dimorphism. The present research provides new standards that better reflect the Japanese people of today. Furthermore, unlike earlier length based formulae, these results allow sexing from fragmentary bones.

Global forensic anthropology in the 21st century

While it has a long history, the last 30 years have brought considerable advances to the discipline of forensic anthropology worldwide. Every so often it is essential that these advances are noticed and trends assessed. It is also important to identify those research areas that are needed for the forthcoming years. The purpose of this special issue is to examine some of the examples of research that might identify the trends in the 21st century. Of the 14 papers 5 dealt with facial features and identification such as facial profile determination and skull-photo superimposition. Age (fetus and cranial thickness), sex (supranasal region, arm and leg bones) and stature (from the arm bones) estimation were represented by five articles. Others discussed the estimation of time since death, skull color and diabetes, and a case study dealing with a mummy and skeletal analysis in comparison with DNA identification. These papers show that age, sex, and stature are still important issues of the discipline. Research on the human face is moving from hit and miss case studies to a more scientifically sound direction. A lack of studies on trauma and taphonomy is very clear. Anthropologists with other scientists can develop research areas to make the identification process more reliable. Research should include the assessment of animal attacks on human remains, factors affecting decomposition rates, and aging of the human face. Lastly anthropologists should be involved in the education of forensic pathologists about osteological techniques and investigators regarding archaeology of crime scenes.

Postmortem skeletal lesions.

Postmortem bone alterations are very frequent and can raise the issue of their nature (antemortem, perimortem or postmortem defects). The aim of this work is to study various aspects of defects which were not assessed as perimortem trauma, from a series of 50 defects examined, resulting from 24 forensic cases. This study emphasizes the variability of size, shape and number of postmortem defects. Usually the diagnosis of antemortem defects is helped by a careful examination of some characteristics as the edges of the defects, the areas of discoloration of the edges and of the whole bone. Elsewhere it appears very difficult to know the true nature (antemortem, postmortem, or perimortem alterations) of the bone.

Sexual dimorphism in modern Japanese crania

The Japanese population has gone through significant micro‐evolutionary changes during the last half century. One approach to quantify these changes is an osteometric analysis of sexual variation in the skeleton. The present study evaluates sexual dimorphism in modern Japanese cranial dimensions. Comprehensive osteometric data were obtained from 84 modern Japanese skeletons of known sex and age at death from the dissecting room collection at Jikei Medical University, Tokyo. The remains were macerated between 1960 and 1970 and thus are from individuals who lived through World War II. A total of 16 cranial dimensions were subjected to SPSS‐X discriminant function analysis. Using 11 measurements of the cranium, five dimensions were selected by the stepwise discriminant methods, including bigonial breadth. In a second stepwise function using 11 cranial measurements, seven contributed to the function. In both functions, mastoid height was selected first and prediction accuracy averaged 84%. Because of its significant contribution, a function was calculated from mastoid height alone. This produced an average of 74% prediction accuracy. In general, width dimensions better reflected differences between the sexes. The accuracy of correct classification from the Jikei sample was slightly lower than those of earlier Japanese populations. The results of this study also suggested that sexual dimorphism in Japanese crania may have decreased as a result of an increase in size of females.

Intercostal variation at the sternal end of the rib

The human rib has proven to be an important site for the assessment of age at death in the adult skeleton. The rib phase method, featuring race and sex specific standards developed by two of the authors (Işcan and Loth), is proving successful in paleodemography and forensic anthropology. However, as the authors pointed out in earlier publications, it is not always possible to isolate the fourth rib upon which the standards are based. This can be a factor because although a certain degree of intercostal variation does exist, its extent has not been quantified in a modern forensic population. Therefore the purpose of this paper is to determine if standards from the fourth rib can be used for adjacent ribs 3 and 5. Ribs 3, 4, and 5 were collected at autopsy from recent medical examiners cases of known age, sex and race. The sample consists of 135 white males and females of age range 3-99 years. Each rib was assigned to an age phase using the established standards. The results of this analysis indicated that > 79% of cases, all three ribs fell into the same phase, and intercostal differences were within one phase for 98% of the sample. It may thus be concluded that age can also be assessed from these adjacent ribs using the present standards.

Assessment of enamel hypoplasia in a high status burial site

Social differentiation is a characteristic of all societies, and higher social status is often associated with better nutrition and good health. Traditional archeologically inferred social status has been linked with biological evidence such as skeletal robusticity and the incidence of disease. In this regard, linear enamel hypoplasia (LEH) is considered a good indicator of health, and individuals with a high status should, at least in theory, not suffer from severe defects. In order to test this hypothesis, the prevalence and occurrence of LEH were assessed in a skeletal sample at the Fort Center, Florida, site. Located near Lake Okeechobee, this site was occupied from about A.D. 200–800, and was considered a mortuary ceremonial center. These archeological findings suggested that individuals buried there belonged to a high class and merited special mortuary rituals. Although 1,835 teeth were found, only 679 maxillary and 393 mandibular teeth were analyzed. The upper I1 and lower C are reported to be most representative for LEH, and were thus selected for further analysis. There were 45 left incisors and 48 left canines. Results indicated that about 95% of incisors and 98% of canines were affected. The occurrence of severe hypoplastic lines was much lower (between 30% and 40%). The minimum number of defects affecting the canine surpassed three, thus showing evidence of repeated stress during childhood. Hypoplasia was first observed between the ages of 1.0 and 1.5 years for incisors and between 2.0 and 2.5 years for canines. Severe defects were first noted to occur at 2.5–3.0 years of age for incisors and 3.0–3.5 years for canines. In conclusion, the high frequency of LEH in this socially elite population seems to prove that in prehistory even privileged classes were severely subjected to stress and the social stratification alone was not sufficient to buffer them from rigorous environments. Am. J. Hum. Biol. 9:213–222, 1997.

Bevelling in exit gunshot wounds in bones.

The analysis of trauma to the skeleton is an important aspect of forensic case work, but most major pathology references devote limited attention to this topic. The aim of this paper is to analyze bevelling in exit gunshot wounds from a series of 14 cases with 17 exit wounds. Assessment of bevelling was made by measuring the endocranial and ectrocranial size of the wound, locating the most pronounced bevelling, and determining if there is a correlation between the direction of bevelling and the direction of shooting. The results indicate outward bevelling of exit wounds in nearly two thirds of cases. No bevelling was observed in the orbits, sphenoid, and in some cases, the occipital and parietal bones. Internal bevelling of exit wounds was not found in this series. Bevelling may be partly understood using a glass model. The inconsistent correlation of the direction of bevelling in exit wounds with the direction of shooting leads to the conclusion that this characteristic cannot be relied upon to determine the direction of fire.

Forensic anthropology in Turkey

Research in skeletal biology has a long history in Turkey, but the shift towards the study of contemporary people has recently been stimulated by the need for appropriate techniques for forensic application. There is an increasing need for data to determine if population-specific standards for age and stature estimation and sex determination are necessary and if so, to develop them. The purpose of this paper is to outline the development of forensic anthropology in Turkey. As has been the case elsewhere, forensic anthropology has its roots in physical anthropology. In Turkey, distinguished pioneers in physical anthropology, such as Sevket A. Kansu and Muzaffer S. Senyürek, focused on the skeletal biology of the historic and prehistoric inhabitants of Anatolia. Today, research programs are under way in the Institute of Forensic Medicine in Istanbul and the Department of Physical Anthropology in Ankara to include the collection of data on modern Turks. A number of projects dealing with various aspects of forensic anthropology are already in progress, e.g., development of age and sex determination standards for the Turkish population. In addition, several graduate students have also chosen research topics in this field.