Anthropological and Radiographic Comparison of Antemortem Surgical Records for Identification of Skeletal Remains*

Abstract: This case review illustrates the important contributions of forensic archeological methods and forensic anthropological analysis to the identification of found skeletal remains. After reassociation of skeletal remains found in two locations, anthropological analysis provided the basis for a presumptive identification and a request for antemortem medical records. Partial DNA profiles were supportive but not conclusive and antemortem dental records were not available. Comparison of antemortem traumas, skeletal morphology, and surgical artifacts with antemortem radiographs and surgical records led to positive identification of an individual missing for almost a decade.     

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.     

Morphological variations in ulnar supinator crests and fossae as identifying markers of occupational stress

Recent morphometric studies of ulnae of prehistoric skeletal remains from populations known to have used spears, atlatls, and similar projectile weapons for hunting and warfare reveal a high incidence of hypertrophy of the ulnar crest, to which the supinator muscle is attached, along with pronounced depth of the adjacent supinator fossa, especially in the upper extremities of males. Similar features occur in the right ulnae of living persons of both sexes who are habitually engaged in certain occupational and athletic activities involving angular displacement of the forearm as a result of medial rotation of the arm at the shoulder, shoulder and arm rapid extension, and abrupt shifts from forearm supination to pronation. Aside from its forensic science implications in determination of right- or left-handedness as a trait peculiar to the individual, observation of these markers of stress on the proximal end of the ulna are significant in identification of skeletal remains of persons known to have engaged in specific brachial activities during life. The biomechanics of these movement patterns and activities in which they occur, when properly interpreted, are relevant to forensic science problems of individual identification and paleoanthropological studies of occupational stress factors in extinct populations for which a skeletal record is available.     

Survival of Atherosclerotic Calcifications in Skeletonized Material: Forensic and Pathological Implications

Atherosclerosis is a chronic inflammatory disease creating calcifying plaques in the arterial walls. Because its paleopathological diagnosis remains little studied on skeletal remains, its impact on forensic and archeological data is completely underestimated. Here, 24 skeletal remains from the Milano Cemetery Skeletal Collection have been studied to evaluate the chance of atherosclerotic calcification survival, retrieval, and identification. Through direct comparison with a known autopsy collection and literature, the identification and categorization of several types of calcifications were performed. Clothing elements such as tights or socks played a definitive role in the preservation of the calcifications; hence they are more likely to be found in forensic cases than in archeological ones. Therefore, vascular calcifications are possible to collect and identify in skeletal remains if sufficient care is given to their recovery. Consequently and as markers of the disease, such identification can provide valuable pathological information for forensic and archeological cases.     

The Correlation Between Skeletal Weathering and DNA Quality and Quantity*

Abstract: Mitochondrial DNA analysis of skeletal material is invaluable in forensic identification, although results can vary widely among remains. Previous studies have included bones of different ages, burial conditions, and even species. In the research presented, a collection of human remains that lacked major confounders such as burial age, interment style, and gross environmental conditions, while displaying a very broad range of skeletal degradation, were examined for both mitochondrial DNA (mtDNA) quality and quantity. Overall skeletal weathering, individual bone weathering, and bone variety were considered. Neither skeletal nor bone weathering influenced DNA quality or quantity, indicating that factors that degrade bone do not have the same effect on DNA. In contrast, bone variety, regardless of weathering level, was a significant element in DNA amplification success. Taken together, the results indicate that neither skeletal nor individual bone appearance are reliable indicators of subsequent mtDNA typing outcomes, while the type of bone assayed is.     

The forensic evaluation of burned skeletal remains: A synthesis

In recent years, research and case experience have greatly augmented knowledge regarding the effects of extreme heat on skeletal remains. As a result of this effort, enhanced interpretation is now possible on such issues as the extent of recovery, reconstruction, trauma, individual identification, size reduction, thermal effects on histological structures, color variation, the determination if remains were burned with or without soft tissue, DNA recovery and residual weight. The rapidly growing literature in this area of forensic science includes experimental research that elucidates the dynamics of the thermal impact on skeletal structure and morphology.     

Building faces from dry skulls: are they recognized above chance rates?

Methods of facial approximation have successfully aided the identification of deceased individuals. Successes may be due to either accurate facial approximation techniques or chance. This study aims to determine if any of 16 facial approximations, built using standard techniques, are sufficiently accurate to produce correct identifications of target individuals above chance. Four skulls were approximated using four commonly used methods of facial approximation. The resulting 16 facial approximations were judged by 37 assessors of varying ages. Assessors attempted to identify the target individual of each facial approximation from a face pool of ten photographed faces. Only one facial approximation resulted in true positive identification rates above chance at statistically significant levels. It is concluded that it is rare for facial approximations to be sufficiently accurate to allow identification of a target individual above chance. Since 403 incorrect identifications were made out of 592 identification scenarios, facial approximation should be considered to be a highly inaccurate and unreliable forensic technique. These results suggest that facial approximations are not very useful in excluding individuals to whom skeletal remains may not belong. Evidence from this experiment supports suggestions by others that facial approximation should be used in forensic science when all other methods of identification have failed and only to provide tentative identification.     

Discriminant function analysis for sex assessment in pelvic girdle bones: sample from the contemporary Mexican population

Sex assessment of skeletal remains plays an important role in forensic anthropology. The pelvic bones are the most studied part of the postcranial skeleton for the assessment of sex. It is evident that a population-specific approach improves rates of accuracy within the group. The present study proposes a discriminant function method for the sex assessment of skeletal remains from a contemporary Mexican population. A total of 146 adult human pelvic bones (61 females and 85 males) from the skeletal series pertaining to the National Autonomous University of Mexico were evaluated. Twenty-four direct metrical parameters of coxal and sacral bones were measured and subsequently, sides and sex differences were evaluated, applying a stepwise discriminant function analysis. Coxal and sacra functions achieved accuracies of 99% and 87%, respectively. These analyses follow a population-specific approach; nevertheless, we consider that our results are applicable to any other Hispanic samples for purposes of forensic human identification.     

Cognitive bias in forensic anthropology: Visual assessment of skeletal remains is susceptible to confirmation bias

An experimental study was designed to examine cognitive biases within forensic anthropological non-metric methods in assessing sex, ancestry and age at death. To investigate examiner interpretation, forty-one non-novice participants were semi randomly divided into three groups. Prior to conducting the assessment of the skeletal remains, two of the groups were given different extraneous contextual information regarding the sex, ancestry and age at death of the individual. The third group acted as a control group with no extraneous contextual information. The experiment was designed to investigate if the interpretation and conclusions of the skeletal remains would differ amongst participants within the three groups, and to assess whether the examiners would confirm or disagree with the given extraneous context when establishing a biological profile. The results revealed a significant biasing effect within the three groups, demonstrating a strong confirmation bias in the assessment of sex, ancestry and age at death. In assessment of sex, 31% of the participants in the control group concluded that the skeleton remains were male. In contrast, in the group that received contextual information that the remains were male, 72% concluded that the remains were male, and in the participant group where the context was that the remains were of a female, 0% of the participants concluded that the remains were male. Comparable results showing bias were found in assessing ancestry and age at death. These data demonstrate that cognitive bias can impact forensic anthropological non-metric methods on skeletal remains and affects the interpretation and conclusions of the forensic scientists. This empirical study is a step in establishing an evidence base approach for dealing with cognitive issues in forensic anthropological assessments, so as to enhance this valuable forensic science discipline.     

The effects of skeletal preparation techniques on DNA from human and non-human bone

The forensic pathologist increasingly relies on the forensic anthropologist to be the consulting expert in human identification. Likewise, if identification is not possible from visual inspection of skeletal remains, the forensic biologist may be called upon to conduct DNA analysis. The possibility of downstream DNA testing needs to be considered when skeletal preparation techniques are employed to deflesh human remains, as they have the potential to strongly impact genetic analyses and subsequent identification. In this study, three cleaning techniques, boiling bone in water, in bleach, and in powdered detergent/sodium carbonate, were tested for their effect on nuclear and mtDNA recovery from a variety of human and non-human bones. A statistically significant reduction in DNA yields occurred in non-human bones cleaned with bleach, and DNA degradation was apparent electrophoretically. The human bones also showed much lower yields from bleach cleaning, while the detergent/carbonate method allowed the largest segments of DNA to be amplified, indicating it may have a less degradative effect on bone DNA than either of the other cleaning processes.     

Forensic osteological investigations in Kosovo

A team of Finnish forensic experts performed investigations of alleged mass graves in Kosovo under the mandate of the European Union (EU). Human skeletal remains from two locations were examined. The remains contained three almost complete skeletons, and individual bones and bone fragments, part of which were burned. Injuries, pathological changes, and findings for identification purposes were examined and documented using standard methods of forensic pathology and osteology. Gunshot injuries were found in some cases, but reliable determination of the cause and manner of death was not possible. A discrepancy arose between the number of victims reported in information received from the presiding district court, and results of the investigations. The estimation of the minimum number of victims was mostly acquired by DNA analysis.     

Identification of group affinity from cross-sectional contours of the human midfacial skeleton using digital morphometrics and 3D laser scanning technology

Identifying group affinity from human crania is a long-standing problem in forensic and physical anthropology. Many craniofacial differences used in forensic skeletal identification are difficult to quantify, although certain measurements of the midfacial skeleton have shown high predictive value for group classifications. This study presents a new method for analyzing midfacial shape variation between different geographic groups. Three-dimensional laser scan models of 90 crania from three populations were used to obtain cross-sectional midfacial contours defined by three standard craniometric landmarks. Elliptic Fourier transforms of the contours were used to extract Fourier coefficients for statistical analysis. After cross-validation, discriminant functions based on the Fourier coefficients provided an average of 86% correct classifications for crania from the three groups. The high rate of accuracy of this method indicates its usefulness for identifying group affinities among human skeletal remains and demonstrates the advantages of digital 3D model-based analysis in forensic research.     

Radiographic human identification using bones of the hand: a validation study

The 1993 Supreme Court case Daubert v. Merrell-Dow Pharmaceuticals, Inc. underscores the importance of validating forensic science techniques. This research examines the validity of using posterior-anterior radiographs of the hand to make positive identifications of unknown human remains. Furthermore, this study was constructed to satisfy the requirements of Daubert's guidelines of scientific validity by establishing a standard methodology for hand radiograph analysis, testing the technique, and noting rates of error. This validation study required twelve participant examiners from the forensic science community, working independently, to attempt to match 10 simulated postmortem radiographs of skeletonized hands to 40 simulated antemortem radiographs of fleshed cadaver hands. The overall accuracy rate of the twelve examiners was 95%, while their collective sensitivity and specificity were 95% and 92%, respectively. However, the accuracy of each examiner was related to the amount of radiological training and experience of the observer. Six Ph.D. forensic anthropologists and four experienced forensic anthropology graduate students correctly identified all the matches. Participant examiners noted bone morphology, trabecular patterns of the proximal and middle phalanges, and distinctive radiopaque and radiolucent features as the anatomical features that aided the identification process. The hand can be an important skeletal element for radiographic positive identification because it contains 27 individual bones for comparative analysis.     

The reliability of forensic osteology--a case in point. Case study

The medico-legal investigation of skeletons is a trans-disciplinary effort by forensic scientists as well as physical anthropologists. The advent of DNA extraction and amplification from bones and teeth has led to the assumption that morphological assessment of skeletal remains might soon become obsolete. But despite the introduction and success of molecular biology, the analysis of skeletal biology will remain an integral part of the identification process. This is due to the fact, that the skeletal record allows relatively fast and accurate inferences about the identity of the victim. Moreover, a standard biological profile may be established to effectively narrow the police investigator's search parameters. The following study demonstrates how skeletal biology may collaborate in the forensic investigation and support DNA fingerprinting evidence.In this case, the information gained from standard morphological methods about the unknown person's sex, age and heritage immediately led the police to suspect, that the remains were that of a young man from Vietnam, who had been missing for 2.5 years. The investigation then quickly shifted to prove the victim's identity via DNA extraction and mtDNA sequence analysis and biostatistical calculations involving questions of kinship [4].     

Guidelines for the recognition of cemetery remains in Greece

Forensic pathologists frequently consult anthropologists for the identification of skeletonized human remains. These remains may be the result of criminal activity or remains that were unearthed because of erosion, or during construction projects. In some cases, human remains that had been previously buried in a cemetery may be the subject of a forensic investigation. Early recognition of cemetery remains prevents unnecessary efforts and conserves precious resources. One of the key characteristics of cemetery remains is the presence of embalmed tissue. However, there are countries where embalming is not a common practice, and other clues must be sought for identifying previously buried remains. Current funerary customs in Greece and, in particular, the tradition of exhumations result in a large number of misplaced human remains. The present study presents examples of cemetery remains from Greece and offers guidelines for recognizing changes on skeletal remains that may be indicative of a cemetery origin. Location of discovery, condition of the remains, and the types of associated artifacts are all factors that aid forensic anthropologists in identifying cemetery remains.     

Recognition by forensic facial approximation: case specific examples and empirical tests

The skeletal remains of one individual found near Adelaide in 1994, although not known at the time, were the first evidence of what was to be a serial killing reported to have resulted in the highest casualty list to date in Australia (12 victims). Since the usual methods of identification could not be used or were unsuccessful on these remains, facial approximations were produced and advertised over the 4-year period following their discovery, in an attempt to help to identify them. However, no identification was made. In 1999, the remains were reported to be identified by radiographic comparison. Approximately 3 months before this identification was made, another facial approximation was produced by the first author (CNS), but this face was never advertised in the media. Although rarely reported in the literature, this paper provides an example where facial approximation methods were not successful in a forensic scenario. The paper also reports on empirical tests of the facial approximation created by the first author to determine if this facial approximation might have been useful had it been advertised. The results provide further evidence that high resemblance of a facial approximation to the target individual does not indicate recognizability, as the facial approximation was poorly recognized even though it bore good resemblance to the target individual. The usefulness of facial approximation techniques is discussed within the context of this case and more broadly. Methods used to assess the accuracy of facial approximations are also discussed and further evaluated.     

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.     

Tooth mark artifacts and survival of bones in animal scavenged human skeletons

Animal scavenging activity can result in production of tooth mark artifacts. Such activity can confound interpretation of skeletal material and the identification process. To date, these topics have received limited attention in the forensic science literature. This study discusses the nature of various animal tooth mark artifacts and typical damage to selected bony elements. This study also assesses survivability of various skeletal elements over time. Two major factors that affect which bones are recovered and the amount of damage are circumstances which shelter remains from animals and human population density of the area where the skeleton is recovered.     

Estimation of stature and determination of sex from radial and ulnar bone lengths in a Turkish corpse sample

Determination of sex and estimation of stature are important aspects of forensic identification of an unknown individual. In the absence of pelvis the sex is assessed from long bones and cranium as they both provide high accuracy in sexing. The present study is an attempt to assess sex and stature from long bones of the forearm using recently deceased forensic cases in Istanbul, Turkey. The sample is composed of 80 males and 47 females with an average age of 36 and 30 years, respectively. Length measurements from the radius and ulna were obtained by exposing the epiphyseal ends of the long bones in a fashion similar to dry long bones. Discriminant function statistics showed a sex determination accuracy as high as 96%. Regression analysis was used in stature estimation from these two bones. Ideally osteological remains are necessary to make standards for osteological identification. These materials are not always easy to obtain and those available seem to be less ideal when they do not represent a current population. Forensic anthropologists therefore should develop techniques that utilize autopsy remains.