Biomedical subjects

M Y Işcan

Publications and source records attributed to M Y Işcan.

At least 19 recordsLinked to original sources

PubMed2001

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.

Age Determination by Skeleton↗

PubMed2001

Skeletal remains of Dr. Eugenio Antonio Berríos Sagredo.

It is often noted that even a well-designed osteological technique may not provide accurate results when applied to single forensic cases. Case studies are ideal to test if this concern is valid, and forensic anthropology is a testing ground for applying a population based standard to individual skeletal remains. Secondly, the increasing role anthropologists have played in forensic sciences has aided the medicolegal disciplines in a number of ways. For example, identification of skeletal remains is now more accurate than ever before. Many of these cases have brought perpetrators to court for justice. The purpose of this paper is to use osteological techniques to analyze skeletal remains and make a positive identification. The victim was found partially buried in the sand near El Pinar, Uruguay in 1995. The analysis indicated that the victim was a 45-year old, white, male who was about 170cm tall. Based on preliminary evidence that the victim might be Dr. Eugenio Antonio Berríos Sagredo, a digital superimposition was made using the victim's photograph and the unknown skull. This examination revealed that the skull corresponded consistently with the individual in the photograph. Results were supported by the fact that personal belongings, such as a medal and wrist watch, also pointed to the same individual. Dental records and radiographs when made available later also indicated the same identity. Dr. Berríos was accused of making nerve gas during the dictatorial regime of former Chilean President General Augusto Pinochet. It was also alleged that he made bombs that killed a Spanish diplomat in his laboratory and a Chilean diplomat in Washington, DC. Many complex techniques are often needed to make a positive identification and such was the case for this study. Because of the nature of anthropology as a holistic discipline, such complexity is an integral part of human biology and behavior and can be used successfully in the forensic sciences and medicolegal investigations.

Cause of Death↗

PubMed2000

Forensic anthropology in Latin America.

Forensic anthropology has been one of the fastest growing medico-legal disciplines both in its contribution to the practical needs of the legal system and research accomplishments. New anthropological standards were developed to apply to a specific population of a region. The purpose of this paper is to analyze a large sample of anthropological forensic cases and to review pertinent literature that deals with anthropological standards developed for the population of the continent of Central and South America. Using Uruguay as an example, there was not a single office or anthropologist assigned to analyze human skeletal remains in Uruguay. In 1991 the Laboratorio de Antropología Forense at the Morgue Judicial of Montevideo was created. A total of 189 forensic anthropological cases (276 individuals) were analyzed since this date. Twenty six percent of cases involving human remains were positively identified. The majority came from the Departamento de Montevideo, the largest population district of the country. Most of the cases fell into the 60 to 69 years old age range (35%). Females represented 32% of the total. Since the establishment of the laboratory, the number of forensic cases increased considerably from 20 in 1991 to 40 in 1997. The case studies were accompanied with skull-photo superimposition and facial reconstruction when no other evidence for positive identification was available. This service provided by the laboratory was quickly known to coroners, law enforcement agencies, and other legal authorities and thus utilized not only in Uruguay but also in several other countries in the continent. Because of the obvious need for an anthropologist, there are now university programs to provide forensic anthropological education. Yet, research has lagged behind considerably. Deficiencies are obvious in basic osteological standards of estimating age, calculating stature, determining sex and assessing race that can be applied to populations of the continent. Regional standards are also needed to estimate postmortem interval, to identify culture specific causes of trauma and other forensic phenomena. Some of these can be remedied if there is a database where the available literature is stored and osteometric information is shared.

Age Determination by Skeleton↗

PubMed1999

Osteometric variation in the humerus: sexual dimorphism in South Africans.

There has been a surge of research on forensic anthropology in South Africa. Differences between the populations of this country and others are demonstrated in many studies. Yet, many forensic osteometric techniques based on other populations are still in use. The purpose of the present study is to develop an osteometric sex determination technique using the humerus. The sample is composed of skeletons of 104 whites and 88 blacks from the Dart and Pretoria collections. Six humeral dimensions were initially analyzed using stepwise discriminant function statistics. Humeral head diameter, deltoid tuberosity circumference and epicondylar breadth were individually calculated in order to make the technique usable for fragmented remains. The results indicated that the head and epicondylar diameters are the best in whites to differentiate sexes from each other, while head diameter and maximum length are best in blacks. Accuracy of correct classification was as high as 96% in whites and 95% in blacks. Crossvalidation provided the same accuracy as the original classification. These accuracy percentages are as high as those expected from the femur and tibia. Posterior probability, which measures the percent affiliation of the sample with its original sex group, was also mostly 80% or better. South African collections are ideal for osteometric analysis, because they are still growing in numbers with cross-sectional representatives from the country.

Adult↗

PubMed1999

Medicolegal anthropology in France.

Medicolegal anthropology has a very long history in France. Basic studies on human skeletal remains started as early as the 18th century. The 19th century produced many medical theses and research papers on age, sex, as well as stature estimation. The research proliferated in the first 60 years of the 20th century, much of which is still in use in France and abroad. The later half of the 20th century, however, was dormant in research on human skeletal biology at a time when forensic anthropology was becoming an active field worldwide. In the last decade, medicolegal anthropology took a different perspective, independent of its traditional roots. Research and practice have both been in the professional domain of forensic physicians unlike the situation in many other countries. Population based studies requiring large databases or skeletal collections have diminished considerably. Thus, most research has been on factors of individualization such as trauma, time since death, crime scene investigation, and facial reconstruction. It is suggested that there is a need for cooperation between the forensic physician and anthropologist to further research. This also encourages anthropologists to carry out research and practice that can fulfill the needs of the medicolegal system of the country.

Europe↗

PubMed1999

Characteristics of gunshot wounds in the skull.

The analysis of trauma to the skeleton is an important aspect of forensic case work, but most pathology references devote limited attention to this topic. This paper describes various aspects of gunshot wounds, including entrance and exit patterns, angle and path, range of fire and velocity, and caliber of the bullet, based on observations of a series of known cases. Skeletal remains of 21 victims of gunshot wounds were studied. In most cases, there was documentation of the investigation, autopsy, and victim's identity. Each case was analyzed in terms of wound location, shape, size and exit/entry surface area ratio, beveling, and direction of shooting Skull entry wounds were most often round or oval. Unusual shapes were observed in bones like the mandible and mastoid process, but were also found to be triangular, nearly rectangular or irregular. Tunneling was observed in the mastoid process. The expected internal beveling was obvious in all but one skull. External beveling of an entry wound was only observed in one case (parietal bone). Exit wounds were roughly round, oval, square, and rectangular and were always more irregular than entry wounds. External beveling of exit wounds was observed in most vault bones, but there was none in the orbit, maxilla, greater wing of the sphenoid, temporal, or left occipital bone. Tangential gunshot wounds were seen in a mastoid process, zygomatic process, mandibular ramus and condyle, and occipital condyle. Most of the exit to entry surface area ratios (cm2) varied from 1.4 to 2.0. In four cases the ratio indicated that entrances were larger than exists. In conclusion, understanding of gunshot wound characteristics is an important matter to interpret distance, velocity, direction and sometimes caliber size. Assessment of this nature of gunshot wounds helps reconstruct events surrounding the death.

Adolescent↗

PubMed1998

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.

China↗

PubMed1998

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 Analysis↗

PubMed1998

Age assessment by rib phase analysis in Turks.

The Işcan's phase method for the estimation of adult age at death from the sternal extremity of the fourth rib was introduced in 1983. Over the years, numerous tests have confirmed the reliability of this technique on varied samples. However, no large scale study has been conducted to test the application of this method on a modern white sample geographically, genetically, and culturally diverse from the American white database. Therefore, the purpose of this paper is to apply rib phase standards to a Turkish sample to test if the progression of morphological changes follow the same age sequence. Using a sample of 150 males and 144 females of known age at death, each rib was phased using the standards developed by Işcan and associates in 1984 and 1985. The phase estimations were then subject to an analysis of variance. The results of the study indicated that Turkish ribs show the same morphological characteristics that define the phases at nearly identical ages. Variation as measured by the standard deviation increased from phase 5 on in both sexes. In conclusion, this study demonstrated that the rib phase standards can be accurately applied to Turks. Investigations of this nature are vital because one cannot assume that a method developed from one group is applicable to a distant population, especially in medicolegal proceedings.

Adolescent↗

PubMed1998

Gunshot wounds to the skull: comparison of entries and exits.

Specific features usually allow recognition of entrance and exit wounds in bones. Exits are often more irregular, and usually larger than entrances. The aim of this paper is to compare the size of 17 entrance and exit gunshot wounds from a series of 13 forensic cases. The results of this work confirm the usually accepted fact that exit wounds in bones tend to be larger than the entrances resulting from the same shot. In all but one case the exits were larger than the entrances in this study. Though the bullet loses velocity after penetrating, the ballistic behavior (deformation and instability of the projectile) explains this tendency.

Forensic Anthropology↗

PubMed1998

Analysis of beveling in gunshot entrance wounds.

The analysis of skeletal trauma is an important aspect of forensic case work. Yet most major pathology references devote limited attention to this topic. The aim of this paper is to analyze beveling in gunshot entrance wounds, from a series of 27 cases with a total of 39 wounds. Assessment was made by measuring the external and internal cranial dimensions, describing the area of most pronounced beveling, and correlating the directions of the beveling with the trajectory of the bullet. Results indicated that inward beveling was found in 36 of 39 cases, the absence of beveling in four bones, and actual external beveling in one case. The inconsistency in the direction of most pronounced beveling in reference to the direction of shooting leads to the conclusion that this characteristic cannot be used to make a reliable assessment of the direction of fire.

Adolescent↗

PubMed1998

Sex determination from the ribs of contemporary Turks.

There have been several in-depth studies showing that the sternal extremity of the fourth rib can be used in estimating age as well as in determining sex, as illustrated in North American whites and blacks. Yet biological differences between populations may preclude the cross-application of standards. To test this hypothesis and develop a sex determination standard for the Turkish population, a sample of the sternal ends of the fourth rib was collected from 294 individuals autopsied in Istanbul, Turkey. Dimensions from the superior edge to the inferior one (SI) and the anterior edge to its posterior edge (AP) were measured with a caliper. The sample was divided into three age groups, "young," "old," and "total." Using discriminant function analysis, three formulae were developed, one for each group. The results indicated that SI height is the most dimorphic dimension and that both dimensions together can given an accuracy of 86% to 90%. To reach such an accuracy, the age of the unknown should be estimated, at least whether it is phase 4 or above or below, using the age standards for ribs developed by Işcan and associates. When cross-validation tests are carried out, incorrect formulae reduce accuracy by as much as 20%. Furthermore, it was observed that North American based white sex determination formulae assign many Turkish males into a female category. In conclusion, it is important to note that population and age specificity are essential in determining sex from the rib. Yet its accuracy is as good as, if not better than, many bones of the postcranial skeleton.

Adolescent↗

PubMed1998

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.

Adolescent↗

PubMed1997

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.

Adult↗

PubMed1997

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.

Bone and Bones↗

PubMed1997

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.

Adult↗

PubMed1996

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 subject's 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.

Adult↗

PubMed1995

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.

Anthropometry↗