Forensic Anthropological Methods Research Articles

Correlations between Dental Age, Skeletal Age, and Mandibular Morphologic Index Changes in Turkish Children in Eastern Anatolia and Their Chronological Age during the Pubertal Growth Spurt Period: A Cross-Sectional Study.

In age determination, different methods aiming to obtain the closest result to chronological age have been investigated so far. The most commonly used one among these is the radiological method, which is usually used to evaluate the developmental stages of wrist bones or teeth. In our study, we assessed bone age estimations using the Gilsanz-Ratib atlas (GRA), which has recently become commonly used for children aged 9 to 15 years; evaluated the dental age, determined with Cameriere's European method; conducted morphometric measurements of the mandibular bone; and then examined their relationships with chronological age. The results of our study reveal that, in children during the puberty growth spurt, Cameriere's EU formula might have higher accuracy in estimating chronological age in younger age groups, while the GRA might be more accurate for older ages. Additionally, we conclude that of the mandibular morphometric measurements, condylar height and tangential ramus height show strong positive correlations with age. As a result, we conclude that the morphometric measurements evaluated in the present study can be used as auxiliary methods in forensic anthropology and forensic dentistry.

Human identification: an investigation of 3D models of paranasal sinuses to establish a biological profile on a modern UK population

Medical imaging is a valuable source for facilitating empirical research and provides an accessible gateway for developing novel forensic anthropological methods for analysis including 3D modelling. This is especially critical for the United Kingdom (UK), where methods developed from modern UK populations do not currently exist. This study introduces a new approach to assist in human identification using 3D models of the paranasal sinuses. The models were produced from a database of 500 modern CT scans provided by University College London Hospital. Linear measurements and elliptic Fourier coefficients taken from 1500 three-dimensional models across six ethnic groups assessed by one-way ANOVA and discriminant function analysis showed a range of classification rates with certain rates reaching 75–85.7% (p < 0.05) in correctly classifying age and sex according to size and shape. The findings offer insights into the potential for employing paranasal sinuses as an attribute for establishing the identification of unknown human remains in future crime reconstructions.

Testing the accuracy of the DRNNAGE software for age estimation in a modern Greek sample

Estimation of age-at-death from human skeletal remains is fundamental in forensic anthropology as part of the construction of the biological profile of the individual under study. At the same time, skeletal age-at-death estimation in adults is problematic due to the disparity between chronological and biological age, the important inter-individual variability at the rate of skeletal aging, and inherent biases in the available methodologies (e.g., age mimicry). A recent paper proposed a method for skeletal age-at-death estimation based on multiple anatomical traits and machine learning. A software was also created, DRNNAGE, for the easy implementation of this method. The authors of that study supported that their methods have very high repeatability and reproducibility, and the mean absolute error of the age estimation was ~6 years across the entire adult age span, which is particularly high and promising. This paper tests the proposed methodology on a modern documented Greek sample of 219 adult individuals from the Athens Collection, with age-at-death from 19 to 99 years old. The sample was split into males and females as well as into individuals under and over 50 years old. We also divided the sample in 10-year intervals. First, intra- and inter-observer error was estimated in order to assess repeatability and reproducibility of the variables employed for age-at-death estimation. Then, the validity (correct classification performance) of DRNNAGE for each anatomical region individually, as well as all combined, was evaluated on each demographic separately and on the pooled sample. According to the results, some of the variables showed very low repeatability and reproducibility, thus their use should be cautious. The DRNNAGE software showed overall highly accurate age-at-death estimates for individuals older than 50 years, but poor on younger adults, with only exception the cranial sutures, which performed surprisingly well for all age groups. Overall, these results support the importance of cross-validation and the use of population-specific methods in forensic anthropology.

Anthropological individualization of relics from sarcophagus stored in Vodnjan monastery, Vodnjan, Croatia

Aim: To develop a methodology for the estimation of the preservation of human skeletal remains – the relics in the Vodnjan assembly; to estimate the minimum number of individuals (MNI), sex, and age; to evaluate the physical state of their remains, and to individualize the remains to verify the list of saints allegedly buried at the monastery. Methods: Standard crime scene investigation and forensic anthropology methods were used, including trace evidence marking, photography, minimum number of individuals (MNI) estimation, sex, age, stature estimation, pathological and traumatic changes examination, individuation, and individualization by the comparison to the biography. Results: The total sample of the bones in the Vodnjan relic collection was very poorly preserved. The MNI in the sarcophagus was twenty-two. Of those, three were female, twelve were male, and seven were subadults. Conclusion: The forensic approach to the documentation and analysis of relics was appropriate for this kind of skeletal material. The final identification was not possible because of the poor preservation of skeletal material and the lack of hagiographical (antemortem) data. However, the forensic anthropology approach enabled us to create osteobiographies, and after the comparison with the existing antemortem data, we could not exclude that the remains belonged to the named saints.

OSTEOMETRIC METHOD FOR RECONSTRUCTING THE BIACROMIAL BREADTH OF THE SHOULDERS FROM THE CLAVICLES IN FORENSIC EXAMINATION OF BONE REMAINS

Positive identification of unknown corpses and bone remains often pose significant challenges for practitioners and requires the use of forensic anthropological methods. The purpose of this study was to develop new methods for reconstructing the antemortem biacromial breadth of the shoulders (BAB) using osteometric measurements of the human clavicle. For this purpose, bone samples from two anatomical collections were used: collection of the Department of Anthropology of Lomonosov Moscow State University and collection of the Russian Center for Forensic Medical Examination (Moscow, Russia). The study showed the possibility of correct reconstruction of BAB using regression equations with expanded (13) or reduced (3-5) sets of osteometric parameters. The methods described in the article can be applied both in forensic context and in anthropological studies.

Smile photograph analysis and its connection with focal length as one of identification methods in forensic anthropology and odontology

To positively identify a highly decomposed body forensic experts often use information obtained from the dentition. In this study authors try to employ a method of comparing incisal borders of the anterior teeth from antemortem (AM) and postmortem (PM) photographs within an experimental scenario with living individuals. The second purpose was to determine how focal length of the lens affects compared smile lines. The research was divided into two stages. In procedure 1, the participants (28 individuals) were asked to provide a photo (for the purpose of the research consideredas "antemortem") in which the anterior teeth were visible. A series of experimental photographs (considered as "postmortem") were then taken trying to reproduce the position of the person's head in relation to "AM" picture as faithfully as possible. The procedure 2 (10 individuals) consisted of taking "AM" photos under controlled conditions using an accidental focal length, then taking "PM" photos using a priori established focal lengths: 18mm, 55mm and 80mm. In both procedures, the final stage involved marking and comparing the incisal borders from "AM" and "PM" photographs. Procedure 1 showed that in 82% of cases the compared smile lines are fully compatible. 11% was marked as "tolerable", and only 2% as "insufficient". Procedure 2 proved that the choice of focal length when taking a PM photograph is significant and that the medium focal lengths (range of 55-85mm) are suggested in case of unknown focal length in AM photo. The results indicate that this method can be reliably applied in forensic cases when AM photographs of deceased are available.

The Identified Osteological Collections of South America and Their Ethical Dimensions

Recent years have brought an important increase in the interest in identified human osteological collections in South America. Their number has been systematically growing and their sizes have been expanding, allowing the development of the field of forensic anthropology, among other disciplines, in this region. These collections are used mainly for the validation of international forensic anthropology methods for national and local populations, as well as for the training of professionals and researchers. Despite their growth, important limitation related to the lack of variability in the representativeness of individuals within these collections represents a significant drawback. Likewise, their concentration in only a few countries constitutes a noteworthy concern. This article aims at mapping the existing identified human osteological collections in South America, discussing the advances in the area of forensic anthropology that they have allowed, and reflecting upon their ethical dimensions in the South American context.

Identification of a decedent in a 103-year-old homicide case using forensic anthropology and genetic genealogy

Anthropologists are often the custodians of long-term unidentified human remains though their positions as curators of university or museum skeletal collections. Various factors decrease the solvability of these legacy cases including the passage of time, the loss of provenience for specific cases, and lack of documentation or case records. While anthropologists can contribute important information toward identification, it is often necessary to explore novel and cross-disciplinary strategies to resolve difficult cold cases. In long cold cases, the postmortem interval, in particular, may be difficult to estimate leading to further challenges in achieving identification. Modern advances in radiocarbon bomb pulse dating, isotope analysis, and actualistic studies have contributed to positive identification of unidentified human remains in some legacy cases, but may not be available to all forensic practitioners and law enforcement from resource-poor agencies. Pooling resources, as well as collaborating with professionals outside of forensic anthropology, is a useful strategy to pursue when anthropological methods are exhausted.The case study presented here demonstrates a collaborative approach between forensic anthropologists, forensic genetic genealogists, and law enforcement in a century-old homicide. The dismembered and mummified parts of a male body were recovered in a remote cave in 1979 and again in 1991. Despite forensic anthropologists creating and updating the biological profile over the decades from recovery to present, no identification was made until the application of forensic genetic genealogy (FGG) to the case in 2019. New interpretations of bone microstructure and trauma analysis are presented for the case, alongside the historical documentation and “proof of life” evidence used by the genealogy team. A review of the FGG methods underscores the challenges in this case (e.g. significant endogamy, multiple aliases used by the victim) and the steps taken toward resolution. Ultimately, a combined anthropology and genealogy approach resulted in a confirmed identity for a man who was murdered in 1916. Key points Forensic scientists should leverage a collaborative, interdisciplinary approach toward human identification. When combined with forensic anthropology methods, forensic genetic genealogy is a valuable tool linking biological and cultural-historical aspects of identity. Forensic anthropologists should review challenging cases in their labs as new methods are introduced and new resources become available.

Reflections on methods to estimate race and ancestry on reference osteological samples in the Brazilian context

The current article is part of the paper presented at the Colloque International Anthropo-Responsabilité (28–29 janvier 2021–musée du quai Branly–Jacques Chirac, Paris). The Teaching and Research Centre of Forensic Archaeology and Anthropology (NEPAAF) at the Laboratory of Archaeological Studies (LEA) from the Federal University of São Paulo (UNIFESP) have developed a pioneer project which deals with the compilation and organization of documentary data (antemortem phase), preparation, curation and bioanthropological analysis of the skeletons (postmortem phase) of an identified osteological collection of the Institute of Teaching and Research in Forensic Sciences (IEPCF) in order to conduct research and provide advanced training in Forensics. The IEPCF collection currently includes 143 unclaimed skeletons with extensive documentation including sex, age-at-death, statute, ancestry, place of birth and death, date of birth/death and cause of death were obtained from the public cemetery records. Identified osteological collections have been traditionally used to develop and test methods in Forensic Anthropology to identify the biological profile through estimation of age-at-death, sex, stature, and ancestry. Given the history of Brazil, the amassing of osteological reference collections is an important a challenge to be overcome to address the reality of violence and death. The main goal of the project is to create an anthropological sample to maximize the research and training potential, and to adapt international standard procedures and methods to Brazilian forensic contexts. Reliminary results from assessing ancestry methods using this collection are presented in this paper to assess some of the ethical and human implications of the continued use of race and ancestry in forensic anthropology. Using a sub-sample of 36 individuals (21 males and 15 females), two major methods were tested for their utility in a forensic context. Both the morphoscopic and metric methods performed poorly. Given the parameters of the blind testing, both methods provided reliable information that matched antemortem records equivalent to chance, and in 47–50% of the cases provide wrong information. The results have implications for the adaption of methods to a forensic context in Brazil, and internationally with respect to human rights investigations.

A four-stage approach to re-associating fragmented and commingled human remains

Bioarchaeological and forensic anthropological methods are limited in their ability to re-associate human skeletal remains that have been both fragmented and commingled. Although many methods for individualizing commingled remains exist, they are rendered ineffective when the level of fragmentation is high. In these contexts, human remains are often approached similarly to faunal assemblages, regarded as sets of fragmented elements rather than as groups of fragments representing an individual. This paper introduces a new, four-stage approach to identifying discrete individuals from unintentionally fragmented and commingled human remains and salvaging information from highly disturbed cemetery contexts. These stages include documentation, grouping, analysis, and evaluation, each incorporating multiple methods so as to be applicable to a wide variety of assemblages or data availability. Through this process, quantitative analyses are used to evaluate qualitative groupings. This method is applicable to skeletal collections of varying levels of preservation. To demonstrate its application, we apply this methodology to an Early Neolithic (7560–6660 HPD cal. BP) hunter-gatherer cemetery, Moty-Novaia Shamanka (MNS), located in the Cis-Baikal region of Siberia, Russia. MNS was destroyed in the 1990s for urban development and flood management, leaving the ancient skeletal remains severely fragmented and commingled. Our results identified five discrete individual groupings from 1245 human bone fragments, and eight further groupings of related fragments. Through a process of elimination, it was determined that these groupings represented at least seven distinct people. The methodological approach of this study challenges our perception of the informative value of fragmented and commingled human remains and provides an example of how future studies could approach individualization in situations where most context has been lost.

Technical note: A report on the Forensic Anthropology Database for Assessing Methods Accuracy.

We report on the functionality, available support, and research capability of the Forensic Anthropology Database for Assessing Methods Accuracy (FADAMA; DOJ DUBX0213). FADAMA is an online repository for case data from identified forensic skeletal cases. The goal of FADAMA is to address the lack of adequate measures for assessing accuracy and reliability of forensic anthropology methods. FADAMA requires users to apply for access with their university or organization credentials. Verified users may upload and download anonymized case data via the user interface, after signing a terms of service agreement outlining ethical behavior. Case data uploads require information about the actual biological profile of the decedent and the forensic anthropology estimations. Uploading case data takes approximately 15-25 min. FADAMA users currently have 85 methods to select from when entering case data, with the capability to add new methods as they are developed. Access to the database is free, and online video tutorials are available for users covering database functionality. Currently, the database houses anonymized case data for over 350 identified cases from across the U.S. Funding has been allocated for a database technician to assist offices with large caseloads to upload cases. As it stands, the database is easy to use, and maintains thoughtful tools to assist users. The power of the database to identify trends in both method accuracy and usage is apparent, and will continue to grow as more cases are added.

Strengthening the role of forensic anthropology in personal identification: Position statement by the Board of the Forensic Anthropology Society of Europe (FASE)

In this position statement, the Board members of the Forensic Anthropology Society of Europe (FASE) argue that forensic anthropology methods can be used as means of personal identification, particularly in situations with limited availability of traditional identification methods (i.e. dactyloscopy, odontology, and molecular genetic analysis). This statement has been issued taking into account the international migration crises related to thousands of deaths worldwide, in which the utility of these traditional means of identification has been sporadic to non-existent. The statement is however not limited to deaths related to the migration crises, as similar problems may occur in fatalities en masse such as in natural disasters and armed conflicts, and on a smaller scale in cases of homeless or otherwise socioeconomically disadvantaged persons. The number of reports on personal identification based on sound anthropological methodology is increasing in the scientific literature. However, more research is needed to develop evidence-based standard operating procedures and statistical frameworks. It remains essential to raise awareness among forensic practitioners, law enforcement, and judiciary professionals on the utility of forensic anthropology in cases where it can provide sufficient information for identification.

Identification of Ajnala skeletal remains using multiple forensic anthropological methods and techniques: A bioarchaeological report

Fragmented and badly damaged commingled human remains present a tough challenge for their identification pursuits in forensic anthropology. Thousands of unknown human remains along with items of contextual identity, reportedly belonging to 282 Indian sepoys killed in 1857, were exhumed mon-scientifically from a disused ancient well at Ajnala (Amritsar, India). In this manuscript, the non-scientific excavation of unknown human remains from the abandoned well, their forensic anthropological strategies for identification purposes, challenges being faced and future possibilities of their biological profiling have been discussed. Multiple methods and techniques like anthropological examinations, odontological profiling, radiological analyses, stable isotope and mitochondrial DNA (mtDNA) analyses were applied to few bones and teeth collected from the Ajnala skeletal assemblage. Though majority of studied bones and teeth were found belonging to adult males, very few of them had morphological, osteological and molecular features questioning the authenticity and validity of the written records. Due to certain ambiguous findings or gaps observed between the anthropological analyses of the Ajnala skeletal remains and the reported versions about their affiliations; certain advanced radiological, chemical and molecular techniques were applied to estimate their probable age, sex and populational affinity. The obtained radiological, isotopic and molecular signatures of the remains were compared with the available databases to estimate their affinity with the individuals of geographic area to whom the remains reportedly belonged to. The maternally inherited mtDNA haplogroup assignments, and stable isotope analysis of carbon and oxygen suggested that the studied human remains belonged to the individuals from West Bengal, Bihar, Odisha, Awadh (presently in Uttar Pradesh) and parts of Meghalaya and Manipur as potential regions of their geographic identity and thus, attributing the victims to be non-local to the site. However, merely on the basis of forensic anthropological examinations of very few bones and teeth (collected out of a huge collection of thousands of bones and teeth); it would be just an unqualified and sweeping conclusion to claim their identity as adult or non-adult, male or female, local or non-local, victims of 1857 mass killings or to the victims of ceremonial sacrifices or criminal activities committed in the past. A sufficient number of bones and teeth along with items of personal identity needs to be examined with multiple scientific techniques to arrive at some valid conclusions about their biological identity.

Virtual forensic anthropology: The accuracy of osteometric analysis of 3D bone models derived from clinical computed tomography (CT) scans

Clinical radiology is increasingly used as a source of data to test or develop forensic anthropological methods, especially in countries where contemporary skeletal collections are not available. Naturally, this requires analysis of the error that is a result of low accuracy of the modality (i.e. accuracy of the segmentation) and the error that arises due to difficulties in landmark recognition in virtual models. The cumulative effect of these errors ultimately determines whether virtual and dry bone measurements can be used interchangeably.To test the interchangeability of virtual and dry bone measurements, 13 male and 14 female intact cadavers from the body donation program of the Amsterdam UMC were CT scanned using a standard patient scanning protocol and processed to obtain the dry os coxae. These were again CT scanned using the same scanning protocol. All CT scans were segmented to create 3D virtual bone models of the os coxae (‘dry’ CT models and ‘clinical’ CT models). An Artec Spider 3D optical scanner was used to produce gold standard ‘optical 3D models’ of ten dry os coxae.The deviation of the surfaces of the 3D virtual bone models compared to the gold standard was used to calculate the accuracy of the CT models, both for the overall os coxae and for selected landmarks. Landmark recognition was studied by comparing the TEM and %TEM of nine traditional inter-landmark distances (ILDs). The percentage difference for the various ILDs between modalities was used to gauge the practical implications of both errors combined.Results showed that ‘dry’ CT models were 0.36–0.45mm larger than the ‘optical 3D models’ (deviations −0.27mm to 2.86mm). ‘Clinical’ CT models were 0.64–0.88mm larger than the ‘optical 3D models’ (deviations −4.99mm to 5.00mm). The accuracies of the ROIs were variable and larger for ‘clinical’ CT models than for ‘dry’ CT models. TEM and %TEM were generally in the acceptable ranges for all ILDs whilst no single modality was obviously more or less reliable than the others. For almost all ILDs, the average percentage difference between modalities was substantially larger than the average percentage difference between observers in ‘dry bone’ measurements only.Our results show that the combined error of segmentation- and landmark recognition error can be substantial, which may preclude the usage of ‘clinical’ CT scans as an alternative source for forensic anthropological reference data.

Sub-adult aging method selection (SAMS): A decisional tool for selecting and evaluating sub-adult age estimation methods based on standardized methodological parameters

ObjectivesA decisional tool was developed to select sub-adult age estimation methods referenced in a centralized database. Through a freely accessible webpage interface, this tool allows users to evaluate how much the sampling and statistical protocols of these referenced methods comply with methodological recommendations published for building and applying methods in forensic anthropology. Materials and methods261 publications on sub-adult age estimation were collected. Three search parameters describing the anatomical element(s) and the indicators used to obtain age estimates are chosen by the user to filter the database and present the publications that best correspond to the user’s selection. A simple algorithm was created to score age estimation methods according to their relevance and validity. “Relevance” and “Validity” parameters indicate how much a publication complies with user queries and published methodological recommendations, respectively; “Score” is a combination of “Relevance” and “Validity”. The closer these parameters are to 1, the better the method complies with the user’s choice and standardized protocols. ResultsThe publications resulting from the user’s query appear as search results alphabetically. They are characterized by their “Relevance”, “Validity” and “Score” values and descriptors relating to their methodology, sampling and statistical protocols. The reference of the publications and an URL to access them online are also provided. ConclusionsSAMS is a decisional tool based on a centralized database for selecting, accessing and evaluating sub-adult age estimation methods based on published methodological recommendations. Protocol validity can be easily and fully accessed to provide the necessary information for method evaluation. The database will be gradually updated and implemented as new sub-adult age estimation methods are made available online.

Age estimation in forensic anthropology: methodological considerations about the validation studies of prediction models

There is currently no clear consensus on how to calculate, express, and interpret the error when validating methods for age estimation in forensic anthropology. For this reason, it is likely that researchers are commonly drawing erroneous or confusing conclusions about the existence of population differences or the need to design new and increasingly complex estimation methods. In recent years, many researchers have highlighted these limitations. They propose new lines of research focused on the use of rigorous statistics and new technologies for the development of methods for estimating age. Our main objective in this study is to contribute to the strengthening of these novel ideas, for which we show the existing empirical evidence about the inadequacy of some age estimation methods in calculating, expressing, and interpreting the errors obtained. With this aim, a total of 500 simulations have been performed, in which hypothetical research teams develop and validate methods for age estimation. The data employed in this study was obtained from the "Centers for Disease Control and Prevention (CDC) Growth Charts: United States" released in 2000. The charts relate age with height, weight, and head circumference of US male children. Five learning algorithms have been employed as age estimators. We have performed three experiments in which the following aspects have been analyzed: frequency with which "negative" results can be obtained in the validation studies; which are the most appropriate criteria to compare and select the age estimation methods; and what analysis should be employed to carry out the validation studies. The results show possible errors in the interpretation of validation studies as a consequence of the confusion of statistical concepts. To conclude, we made a proposal of "good practices" for the correct calculation, expression, and interpretation of the error when validating age estimation methods in forensic anthropology.

An execution in medieval Sicily: Computerised tomography scan analysis and 3D reconstruction of an ancient forensic context

AbstractThe bioarchaeological and forensic approach is increasingly applied in the study of funerary contexts in archaeology. Here, we present a case of an atypical medieval burial recently discovered in Piazza Armerina (Sicily), in which the integrated use of traditional bioarchaeological and forensic anthropology methods was crucial. The skeleton was lying in a prone position and was characterised by a peculiar injury pattern. We recorded six clear stab wound marks on the posterior surface of the sternum. The use of computerised tomography scan and 3D modelling techniques has made it possible to obtain a reliable reconstruction of the cause and modality of death, pointing to the execution of the individual. The importance of this case study is twofold. First, the injury pattern recorded currently constitutes a unicum in the bioarchaeological record. Second, it represents the first well‐documented case of an atypical burial in Sicily.

The accuracy of 3D virtual bone models of the pelvis for morphological sex estimation

It is currently unknown whether morphological sex estimation traits are accurately portrayed on virtual bone models, and this hampers the use of virtual bone models as an alternative source of contemporary skeletal reference data. This study determines whether commonly used morphological sex estimation traits can be accurately scored on virtual 3D pelvic bone elements. Twenty-seven intact cadavers from the body donation program of the Amsterdam UMC, University of Amsterdam, were CT scanned; this data was used to produce virtual bone models. Thereafter, the dry bones were obtained. Three traits by Klales (2012) and five traits from the Workshop of European Anthropologists (WEA) (1980) were scored on the virtual bone models and their dry skeletal counterparts. Intra- and inter-observer agreement and the agreement between the scores for each virtual bone model-dry bone pair were calculated using weighted Cohen’s kappa (K). For all Klales (2012) traits, intra- and inter-observer agreement was substantial to almost perfect for the virtual- and dry bones (K = 0.62–0.90). The agreement in scores in the virtual-dry bone pairs ranged from moderate to almost perfect (K = 0.58–0.82). For the WEA (1980) traits, intra-observer agreement was substantial to almost perfect (K = 0.64–0.91), but results were less unambiguous for inter-observer agreement (K = 0.24–0.88). Comparison of the scores between the virtual bone models and the dry bones yielded kappa values of 0.42–0.87. On one hand, clinical CT data is a promising source for contemporary forensic anthropological reference data, but the interchangeability of forensic anthropological methods between virtual bone models and dry skeletal elements needs to be tested further.

The geometrical precision of virtual bone models derived from clinical computed tomography data for forensic anthropology

Almost all European countries lack contemporary skeletal collections for the development and validation of forensic anthropological methods. Furthermore, legal, ethical and practical considerations hinder the development of skeletal collections. A virtual skeletal database derived from clinical computed tomography (CT) scans provides a potential solution. However, clinical CT scans are typically generated with varying settings. This study investigates the effects of image segmentation and varying imaging conditions on the precision of virtual modelled pelves. An adult human cadaver was scanned using varying imaging conditions, such as scanner type and standard patient scanning protocol, slice thickness and exposure level. The pelvis was segmented from the various CT images resulting in virtually modelled pelves. The precision of the virtual modelling was determined per polygon mesh point. The fraction of mesh points resulting in point-to-point distance variations of 2 mm or less (95% confidence interval (CI)) was reported. Colour mapping was used to visualise modelling variability. At almost all (>97%) locations across the pelvis, the point-to-point distance variation is less than 2 mm (CI = 95%). In >91% of the locations, the point-to-point distance variation was less than 1 mm (CI = 95%). This indicates that the geometric variability of the virtual pelvis as a result of segmentation and imaging conditions rarely exceeds the generally accepted linear error of 2 mm. Colour mapping shows that areas with large variability are predominantly joint surfaces. Therefore, results indicate that segmented bone elements from patient-derived CT scans are a sufficiently precise source for creating a virtual skeletal database.

Metric Methods for the Biological Profile in Forensic Anthropology: Sex, Ancestry, and Stature.

The biological profile, conducted by a forensic anthropologist, is necessary for severely decomposed or skeletonized remains. The biological profile consists of estimates of sex, age, ancestry, and stature. It is crucial to have a correct estimate of sex, as this designation will narrow down the search through missing persons reports by half (e.g., searching through NamUs). However, sex estimates can be population specific, necessitating accurate ancestry estimation. When estimates of age and stature are added, the search narrows further. If these estimates are incorrect, the unidentified human remains may never be identified. These biological profile components are estimated based on either metric or nonmetric methods (visual observation and recording of categorical data). While age is inherently nonmetric, stature is inherently metric. Estimates of sex and ancestry can take a metric or nonmetric approach. The purpose of this review article is to review metric methods in forensic anthropology (sex, ancestry, and stature), to provide general knowledge of why and how these metric methods work, and to highlight that estimates of sex, ancestry, and stature do not subscribe to a "one size fits all" model.