Determination of age from the sternal rib in white males: a test of the phase method

The effectiveness of a given age determination technique can better be assessed by testing the standards on unknown specimens. A test of this nature was carried out to evaluate the authors' previously published phase method for age estimation from the sternal extremity of the rib. A sample of 15 test ribs was judged by 25 physical and forensic anthropologists with varying levels of education and experience. The judges were asked to match the rib to the phase it most closely resembled by comparing it with the photographs from the original study. The results indicated that interobserver error based on experience was minimal, and nearly all of the participants averaged within one phase of the ideal. Variation appeared to be greater among the ribs than among the judges, yet no consistent association could be made between this variation and factors such as cause of death, antemortem medical history, drug or alcohol abuse, and occupation.     

Forensic anthropology in the 1990s.

Forensic anthropology has undergone considerable change over the past 10 years. Today it is utilized by most law enforcement, coroner, and medical examiner systems. The techniques for determination of age at death, sex, race, and stature from skeletal remains have been modified and greatly expanded. The role of the forensic anthropologist within a medicolegal context is much broader than in previous years. In addition to establishing individual identity, forensic anthropologists are now consulted for trauma analysis, facial reconstruction, photographic superimposition, determination of time interval since death, and crime-scene recovery. Not all physical anthropologists are forensic anthropologists. Qualified individuals are certified, through rigorous examination, by the American Board of Forensic Anthropology. A list of board-certified forensic anthropologists may be obtained through the American Academy of Forensic Sciences.     

Guidelines for international forensic bio-archaeology monitors of mass grave exhumations

The systematic exhumation of mass graves is becoming a frequent occurrence globally. Historically, it has been mostly anthropologists with their particular expertise in osteology that have been engaged by non-governmental organizations (NGO) to monitor mass grave exhumations and postmortem examinations, conducted by a host country or international forensic team, to ensure competence and a concern for justice. The excavation of graves and examination of their contents for the purposes of personal identification of victims and/or collection of evidence for prosecution require the creation of standards that meet international concerns for forensic investigation of the highest quality. However, many anthropologists are not experienced with large sites; do not have much, if any, expertise in archaeology; and are not equipped by training to assess the quality of a forensic pathologist's autopsy. This contribution is directed to both the NGO and the bio-archaeologist who are involved in the exhumation of mass graves. The experience and skills appropriate for the bio-archaeological monitor are outlined; similarly, the policies and standard operating procedures (SOP's) of the NGO that will enable the bio-archaeologist to perform their task are detailed. It is becoming increasingly clear that how a grave site was created, filled, and concealed, along with subsequent processes of site formation (e.g. slumping, robbing, animal scavenging and taphonomic alteration), require the expertise of a forensic archaeologist to discover and record site complexity along with associated forensic evidence. Similarly, the bodies themselves which are often skeletonized, fragmented and commingled pose challenges for the anthropologists and pathologists whose postmortem examinations must be critically evaluated. A model protocol for observations to make at the site as well as at the mortuary facility is provided to guide the monitor and to provide a structure for reports which are of standardized content suitable for international agencies concerned with mass grave investigation.     

Confidence intervals for estimates based on linear regression in forensic anthropology

Forensic anthropologists commonly use simple linear regression to estimate the value of a dependent variable, such as stature, for a single specimen where the value of the independent variable, such as humerus length, is known. Published studies providing regression equations for such use almost invariably include the standard error of estimate. Unfortunately, it is exceptional for forensic anthropologists to use the standard error to calculate correctly the confidence limits for their single predicted value. We attempt to show why this may be and provide explicit guidelines for the proper construction of confidence interval in such circumstances.     

Dietary health does affect histological age assessment: an evaluation of the Stout and Paine (1992) age estimation equation using secondary osteons from the rib

An age at death estimation equation that uses rib histological variables presented by Stout and Paine was used to evaluate a skeletal population of individuals with a known age at death and cause of death from either malnutrition or the niacin deficiency disease pellagra. The sample was comprised of 26 autopsied black South Africans. Histological analysis of mounted thin sections involved the microscopic measurement of cortical area and a count of the number of intact and fragmentary secondary osteons for the entire cross-section of the rib. Rib osteon population density values were then calculated for each case. It was found that this equation under-aged individuals on average by 29.2 years. Overall, secondary osteon size and Haversian canals tended to be larger than expected, while cortical bone area was less when compared with a control population. The implications of these findings are critical given that many of the skeletal remains examined by forensic anthropologists come from marginalized backgrounds, including malnutrition. This research suggests that measurements based on healthy cases may not be useful in an analysis of individuals with poor diet and health. It is argued that new standards for histological age assessment methods need to be created that account for variation in the health status of individuals examined by forensic anthropologists.     

Evidentiary Standards for Forensic Anthropology*

Abstract: As issues of professional standards and error rates continue to be addressed in the courts, forensic anthropologists should be proactive by developing and adhering to professional standards of best practice. There has been recent increased awareness and interest in critically assessing some of the techniques used by forensic anthropologists, but issues such as validation, error rates, and professional standards have seldom been addressed. Here we explore the legal impetus for this trend and identify areas where we can improve regarding these issues. We also discuss the recent formation of a Scientific Working Group for Forensic Anthropology (SWGANTH), which was created with the purposes of encouraging discourse among anthropologists and developing and disseminating consensus guidelines for the practice of forensic anthropology. We believe it is possible and advisable for anthropologists to seek and espouse research and methodological techniques that meet higher standards to ensure quality and consistency in our field.     

Forensic Applicability of Femur Subtrochanteric Shape to Ancestry Assessment in Thai and White American Males

Ancestry assessment from the postcranial skeleton presents a significant challenge to forensic anthropologists. However, metric dimensions of the femur subtrochanteric region are believed to distinguish between individuals of Asian and non‐Asian descent. This study tests the discriminatory power of subtrochanteric shape using modern samples of 128 Thai and 77 White American males. Results indicate that the samples' platymeric index distributions are significantly different (p ≤ 0.001), with the Thai platymeric index range generally lower and the White American range generally higher. While the application of ancestry assessment methods developed from Native American subtrochanteric data results in low correct classification rates for the Thai sample (50.8–57.8%), adapting these methods to the current samples leads to better classification. The Thai data may be more useful in forensic analysis than previously published subtrochanteric data derived from Native American samples. Adapting methods to include appropriate geographic and contemporaneous populations increases the accuracy of femur subtrochanteric ancestry methods.     

Testing the reliability of frontal sinuses in positive identification

The use of frontal sinus radiographs in positive identification has become an increasingly applied and accepted technique among forensic anthropologists, radiologists, and pathologists. From an evidentiary standpoint, however, it is important to know whether frontal sinus radiographs are a reliable method for confirming or rejecting an identification, and standardized methods should be applied when making comparisons. The purpose of the following study is to develop an objective, standardized comparison method, and investigate the reliability of that method. Elliptic Fourier analysis (EFA) was used to assess the variation in 808 outlines of frontal sinuses by calculating likelihood ratios and posterior probabilities from EFA coefficients. Results show that using EFA coefficient comparison to estimate the probability of a correct identification is a reliable technique, and EFA comparison of frontal sinus outlines is recommended when it may be necessary to provide quantitative substantiation for a forensic identification based on these structures.     

Current practices by forensic anthropologists in adult skeletal age estimation

When determining an age estimate from adult skeletal remains, forensic anthropologists face a series of methodological choices. These decisions, such as which skeletal region to evaluate, which methods to apply, what statistical information to use, and how to combine information from multiple methods, ultimately impacts the final reported age estimate. In this study, a questionnaire was administered to 145 forensic anthropologists, documenting current trends in adult age at death estimation procedures used throughout the field. Results indicate that the Suchey-Brooks pubic symphysis method (1990) remains the most highly favored aging technique, with cranial sutures and dental wear being the least preferred, regardless of experience. The majority of respondents stated that they vary their skeletal age estimate process case-by-case and ultimately present to officials both a narrow and broad possible age range. Overall, respondents displayed a very high degree of variation in how they generate their age estimates, and indicated that experience and expertise play a large role in skeletal age estimates.     

Determination of sex and race from the subpubic angle in Ugandan subjects

The accurate determination of sex and race are important tools to forensic and physical anthropologists. In this study, the sex and race of 205 adult Ugandans were determined from the antero-posterior radiographs of the pelvis by measuring their subpubic angles. The angle ranged from 50 to 140 degrees with a mean of 93.86 degrees and standard deviation (SD) of 21.12 degrees for males and 75 to 155 degrees with a mean of 116.11 degrees (SD, 17.79 degrees) for females. The angle was significantly wider in women than men (P < 0.05), as indeed has previously been shown in other population groups studied. Using the demarking point method, 31.82% of Ugandan men and 10.53% of Ugandan women could be accurately sexed. However, more Malawians of both sexes previously studied had lower values for the angle and could be more accurately sexed. This study has also documented regional and racial variability of this angle among different population groups previously documented. Using the watershed subpubic angle derived from the means of this study and those of previously documented studies, 63% of Ugandans and 71% of Malawians could be accurately assigned to the black race. This method is recommended to physical and forensic anthropologists in the developing world.     

中国黄种人与白种人脑颅骨特征差异初探

目的建立利用脑颅骨特征推断黄种人和白种人种族的判别方程,并评价其法医学意义。方法收集141例成年人脑颅骨样本,其中黄种人60例,白种人81例。选取脑颅骨lO项特征指标,对125例样本进行测量,运用SPSS16．0软件对指标数据进行t检验和Fisher判别分析,建立判别方程。并使用16例样本对方程的判别正确率进行盲测。结果本文选择的10项脑颅骨特征指标变量均具有显著性种族差异（P〈0．05）;建立了5组单项指标和4组多项指标进行种族推断的判别方程,综合判别率为74．4％～94．4％;随机选取16例样本的盲测结果,正确率为81．3％-100％。结论脑颅骨具有种族差异性,本文建立的判别方程可在黄种人和白种人的种族推断中选用。     

Reliable Gait Recognition Using 3D Reconstructions and Random Forests – An Anthropometric Approach

Photogrammetric measurements of bodily dimensions and analysis of gait patterns in CCTV are important tools in forensic investigations but accurate extraction of the measurements are challenging. This study tested whether manual annotation of the joint centers on 3D reconstructions could provide reliable recognition. Sixteen participants performed normal walking where 3D reconstructions were obtained continually. Segment lengths and kinematics from the extremities were manually extracted by eight expert observers. The results showed that all the participants were recognized, assuming the same expert annotated the data. Recognition based on data annotated by different experts was less reliable achieving 72.6% correct recognitions as some parameters were heavily affected by interobserver variability. This study verified that 3D reconstructions are feasible for forensic gait analysis as an improved alternative to conventional CCTV. However, further studies are needed to account for the use of different clothing, field conditions, etc.     

Using accumulated degree-days to estimate the postmortem interval from decomposed human remains

Forensic anthropologists often rely on the state of decomposition to estimate the postmortem interval (PMI) in a human remains case. The state of decomposition can provide much information about the PMI, especially when decomposition is treated as a semi-continuous variable and used in conjunction with accumulated-degree-days (ADD). This preliminary study demonstrates a supplemental method of determining the PMI based on scoring decomposition using a point-based system and taking into account temperatures in which the remains were exposed. This project was designed to examine the ways that forensic anthropologists could improve their PMI estimates based on decomposition by using a more quantitative approach. A total of 68 human remains cases with a known date of death were scored for decomposition and a regression equation was calculated to predict ADD from decomposition score. ADD accounts for approximately 80% of the variation in decomposition. This study indicates that decomposition is best modeled as dependent on accumulated temperature, not just time.     

Cranial Nonmetric Variation and Estimating Ancestry*

Abstract: Historically, when predicting the ancestry of human skeletal remains, forensic anthropologists have not fully considered the variation within human populations, but instead have relied on a typological, experience‐based approach. Unfortunately, reliance on observer experience has produced a method that is as much an art as it is a science. This research focuses on the frequency distribution and inter‐trait correlations of 11 common morphoscopic traits to demonstrate that the experience‐based approach to ancestry prediction is indeed an art that is unscientific, because it is unreplicable, unreliable, and invalid. Ten of 11 traits examined had frequency distributions with significant differences (p < 0.001) between groups, but the range in variation of these traits far exceeds previous assumptions. Such within group variation clearly demonstrates that extreme trait expressions are not reliable for estimating ancestry through visual observation alone, but instead that these traits should be analyzed within a statistical framework.     

The scope of anthropological contributions to human rights investigations

This paper examines the participation of anthropologists in international human rights investigations between 1990 and 1999 by surveying four of the most active organizations, including the Argentine Forensic Anthropology Team, the Guatemalan Forensic Anthropology Foundation, Physicians for Human Rights and the U.N.-sponsored International Criminal Tribunal for the former Yugoslavia. The education level, sex, nationality and primary role of the anthropological members of each team are quantified, as are the types of projects in which they contributed. The results show that 134 anthropologists from 22 nations investigated nearly 1300 sites in 33 countries during the study period. While involvement is not limited to those with advanced degrees and few obstacles are placed before anthropologists who wish to participate, full-time service within these organizations is rare and those interested in a career in forensic anthropology and human rights should understand the employment limitations.     

A fast and safe non-bleaching method for forensic skeletal preparation

Over the last three decades, forensic anthropologists increasingly have consulted on fleshed human remains cases in which the examination of skeletal elements is critical in answering questions of identification and the circumstances of death. This was certainly the case at the Human Identification Laboratory in Tucson, Arizona. As the caseload increased, it became clear that a method for defleshing human remains was needed in order to expeditiously expose the osseous surfaces for analysis, yet at the same time, preserving the evidentiary nature of the material. As a result, a fast, safe and economical method for defleshing human remains and producing high quality, degreased skeletal elements was developed. This non-bleaching cooking method utilizes chemicals that are easily obtained and inexpensive standard household ingredients that can be purchased at most grocery stores.     

Variation in the Measurement of Cranial Volume and Surface Area Using 3D Laser Scanning Technology

Abstract: Three‐dimensional (3D) laser scanner models of human crania can be used for forensic facial reconstruction, and for obtaining craniometric data useful for estimating age, sex, and population affinity of unidentified human remains. However, the use of computer‐generated measurements in a casework setting requires the measurement precision to be known. Here, we assess the repeatability and precision of cranial volume and surface area measurements using 3D laser scanner models created by different operators using different protocols for collecting and processing data. We report intraobserver measurement errors of 0.2% and interobserver errors of 2% of the total area and volume values, suggesting that observer‐related errors do not pose major obstacles for sharing, combining, or comparing such measurements. Nevertheless, as no standardized procedure exists for area or volume measurements from 3D models, it is imperative to report the scanning and postscanning protocols employed when such measurements are conducted in a forensic setting.     

The Use of an Alternate Light Source for Detecting Bones Underwater

When searching underwater crime scenes or disaster scenes for fragmentary human remains, it may be advantageous for forensic divers to be able to detect the presence of bones and teeth among other marine materials (such as shells and rocks). In terrestrial environments, this can typically be accomplished by visual and instrumental methods, but underwater conditions make it difficult to employ detection and sorting techniques in these environments. This study investigates fluorescence of bones and teeth and other marine materials using a submersible alternate light source (ALS) and concludes that an ALS can be a useful tool for detecting bones and teeth in underwater searches as well in terrestrial searches and laboratory environments. The results could impact the methods and equipment used by forensic divers and forensic anthropologists when searching for skeletal remains, potentially increasing the quantity and efficiency of forensic evidence recovered.     

Sexing and stature estimation criteria for Balkan populations

Abstract:  Two standard measurements, maximum femur length and head diameter, were collected by International Criminal Tribunal (ICTY) anthropologists. Only Kosovans had both femur dimensions for both sexes. Antemortem stature data were available only for Kosovan and Croatian males. Despite these limitations, the data offer the opportunity to examine ethnic variation and to present sex and stature estimation criteria for these groups. Additional data from Croatians and from American Whites were used for comparison in certain parts of the analysis. Femur variation was considerable. Kosovans can be characterized as short and robust, Bosnians as tall and less robust, and Croatians are tall and gracile, resembling American Whites more than the other groups. Some limited antemortem data on stature was also available, allowing stature estimation equations to be estimated for Croatians and Kosovans. Antemortem stature estimates were obtained from interviews with relatives and are shown to overestimate actual stature. We argue that equations predicting height obtained from relatives is the most realistic in this case because that is the height to which an estimate obtained from bone lengths will be compared. Kosovans were also shown to have experienced slight secular increase in femur length over the past 70 years.     

Evaluation of cast methods for estimating age from the os pubis.

Age-related changes of the pubic symphysis have gained wide acceptance among physical anthropologists as one basis for estimating adult skeletal age. However, these methods have not been tested by independent observers on large samples with known ages at death that represent contemporary populations. In this study 202 female and 116 male pairs of pubes collected at autopsy were blindly evaluated for age using the McKern-Stewart or Gilbert-McKern and Suchey-Brooks methods. Performance of the methods was measured by mean absolute deviation of true age from scored interval means and frequencies of true age falling within +/- 1 and +/- 2 standard deviations from the mean. The results suggest that the Suchey-Brooks methods are superior in forensic applications and that the racially specific refinement for males should be used. Age estimates should include +/- 2 standard deviations, and chances of error should be considered, especially when advanced age or debilitation is suspected.