Craniofacial identification standards: A review of reliability, reproducibility, and implementation.

There are numerous anatomical and anthropometrical standards that can be utilised for craniofacial analysis and identification. These standards originate from a wide variety of sources, such as orthodontic, maxillofacial, surgical, anatomical, anthropological and forensic literature, and numerous media have been employed to collect data from living and deceased subjects. With the development of clinical imaging and the enhanced technology associated with this field, multiple methods of data collection have become accessible, including Computed Tomography, Cone-Beam Computed Tomography, Magnetic Resonance Imaging, Radiographs, Three-dimensional Scanning, Photogrammetry and Ultrasound, alongside the more traditional in vivo methods, such as palpation and direct measurement, and cadaveric human dissection. Practitioners often struggle to identify the most appropriate standards and research results are frequently inconsistent adding to the confusion. This paper aims to clarify how practitioners can choose optimal standards, which standards are the most reliable and when to apply these standards for craniofacial identification. This paper describes the advantages and disadvantages of each mode of data collection and collates published research to review standards across different populations for each facial feature. This paper does not aim to be a practical instruction paper; since this field encompasses a wide range of 2D and 3D approaches (e.g., clay sculpture, sketch, automated, computer-modelling), the implementation of these standards is left to the individual practitioner.

Are computed tomography images of the mandible useful in age and sex determination? A forensic science meta-analysis.

OBJECTIVES: This meta-analysis addresses the use of mandibular computed tomography (CT) scans for age and/or sex determination in forensic science. METHODS: Six databases were searched until June 2023, using the keyword "mandible" combined with keywords related to "multislice computed tomography" (MCT) or "cone-beam computed tomography" (CBCT) and keywords related to "skeletal age determination" or "sex determination analysis." MAIN RESULTS: Among the 23 studies included, 11 used MCT and 12 used CBCT to perform forensic assessments. Age determination was the aim of a single study, sex and agedeterminations were the objective of five studies, and the other studies investigated the determination of sex only. Metaanalysis could be performed only for sex determination. CONCLUSIONS: Mandible measurements are useful in sex determination, as the bicondylar and bigonial breadth are larger in males than in females. For the mandible angle, the meta-analysis results confirm sex dimorphism in CBCT scans but not in MCT scans. For age estimation, further studies are needed to prove that the mandible hole is a reliable parameter for age estimation. PROSPERO registration number: CRD42021260967.

The utility of sternum in creating a biological profile: A review and future directions.

This review delves into the forensic utility of the sternum in creating a biological profile, focusing on sex, stature, and age estimation. Emphasizing the sternum's significance in challenging scenarios, the study supports the combined length of the manubrium and sternal body as a crucial indicator in sex and stature estimation. However, it highlights the need for caution in applying findings across diverse populations and questions the reliability of Hyrtl's law. Age estimation, primarily based on morphological changes and ossification ages, is explored, with one study showing promise but requiring further validation. While acknowledging the sternum's advantages, the review underscores potential limitations and the absence of specific studies on ancestry estimation, leaving this aspect open for future research. In conclusion, the review provides a comprehensive overview of the sternum's forensic applications, urging continued research to enhance accuracy and applicability.

Phylogenetic analysis of mysterious burials revealed in the former penal labor camp Treblinka I.

The purpose of this paper is to formulate recommendations for the disclosure of biological traces in the laboratory and the handling of forensic evidence submitted for identification tests, recommended by the Polish Speaking Working Group of the International Society for Forensic Genetics. The paper organizes the knowledge of the most relevant stages of preliminary analysis of biological traces based on both literature sources and those resulting from years of research practice. Recommendations formulated in the course of multi-stage expert consultations contained in this study should be used in the development of laboratory procedures applied during the execution. * The research is part of doctoral dissertation of Dagmara Lisman entitled "Genetic analysis of a skeleton site revealed during the works on the premises of the former German Forced Labor Camp Treblinka I."

Age Estimation Based on Computed Tomography Analysis of the Scapula.

Background and Objectives: Age estimation from skeletal remains and in living individuals is an important issue for human identification, and also plays a critical role in judicial proceedings for migrants. Forensic analysis of ossification centers is the main evaluation method for age estimation, and ossification degree can be determined using computed tomography analysis. The purpose of this study is to investigate the applicability of CT (computed tomography) in the analysis of left scapula ossification centers, for forensic age estimation in Turkish society. Materials and Methods: We analyzed six ossification centers of the left scapula and these ossification centers are the coracoid, subcoracoid, coracoid apex, acromial, glenoid, and inferior angle ossification centers. A pediatric radiologist analyzed these six ossification centers of the scapula by using a staging method defined by Schmeling et al. in 2004. Two months after the first assessment, 20 randomly selected cases was reanalyzed by the first observer and by another pediatric radiologist. Correlation between the age and ossification stage was assessed using Spearman's nonparametric correlation test. Linear regression analysis was performed using a backwards model. Cohen's kappa coefficient was used for evaluating interobserver and intraobserver variability. Results: In this retrospective study, 397 (248 male and 149 female) cases were evaluated. Ages ranged between 7.1 and 30.9. The mean age was 19.83 ± 6.49. We determined a positive significant correlation between the age and the ossification stages of ossification centers analyzed in both sexes. In each ossification center, except inferior angle, all of the stage 1 and 2 cases in both sexes were under 18 years old. Intraobserver and interobserver evaluations showed that reproducibility and consistency of the method was relatively good. Conclusions: The present study indicated that CT analysis of scapula ossification centers might be helpful in forensic age assessment of living individuals and dry bones.

Sex estimation in the South-East Asian population: A systematic review.

INTRODUCTION: Sex estimation is crucial in forensic anthropology. In situations such as mass disasters, and forensic anthropology cases, sex estimation is a very important initial step in the disaster victim identification process. Literature has acknowledged that sex estimation is population-specific. However, sex estimation standards in South-East Asian populations are limited, leading to the usage of most Thais discriminant function equations on sex estimation by other South-East Asian countries including Malaysia. This systematic review was conducted to summarise the findings of sex estimation studies in South-East Asian countries. MATERIALS AND METHODS: A systematic literature search was performed through the SCOPUS database and Web of Science (WOS) database for relevant studies between 2014 and 2022. All published articles that are related to sex estimation from different types of bone, methods, landmarks, and sample sources (i.e., photographs, dry bones, and CT images) were included in this review. The main inclusion criteria were studies on (i) sex estimation; (ii) in South-East Asian populations; (iii) between the years 2014 and 2022; and (iv) in English. RESULTS: The literature search identified 30 potentially relevant studies, of which 15 publications met all the inclusion criteria. From those research, 13 studies were related to the Thai population and two to the Malaysian population. Only one study was based on morphological traits, while the rest were based on a morphometric approach. CONCLUSION: All studies found that sex estimation is populationspecific. Therefore, further research is recommended to explore more on population-specific sex estimation using different parts of bone.

Automated reconstruction: Predictive models based on facial morphology matrices.

Forensic Facial Approximation (FFA) has evolved, with techniques advancing to refine the intercorrelation between the soft-tissue facial profile and the underlying skull. FFA has become essential for identifying unknown persons in South Africa, where the high number of migrant and illegal labourers and many unidentified remains make the identification process challenging. However, existing FFA methods are based on American or European standards, rendering them inapplicable in a South African context. We addressed this issue by conducting a study to create prediction models based on the relationships between facial morphology and known factors, such as population affinity, sex, and age, in white South African and French samples. We retrospectively collected 184 adult cone beam computed tomography (CBCT) scans representing 76 white South Africans (29 males and 47 females) and 108 French nationals (54 males and 54 females) to develop predictive statistical models using a projection onto latent structures regression algorithm (PLSR). On training and untrained datasets, the accuracy of the estimated soft-tissue shape of the ears, eyes, nose, and mouth was measured using metric deviations. The predictive models were optimized by integrating additional variables such as sex and age. Based on trained data, the prediction errors for the ears, eyes, nose, and mouth ranged between 1.6 mm and 4.1 mm for white South Africans; for the French group, they ranged between 1.9 mm and 4.2 mm. Prediction errors on non-trained data ranged between 1.6 mm and 4.3 mm for white South Africans, whereas prediction errors ranging between 1.8 mm and 4.3 mm were observed for the French. Ultimately, our study provided promising predictive models. Although the statistical models can be improved, the inherent variability among individuals restricts the accuracy of FFA. The predictive validity of the models was improved by including sex and age variables and considering population affinity. By integrating these factors, more customized and accurate predictive models can be developed, ultimately strengthening the effectiveness of forensic analysis in the South African region.

Considerations for age estimation accuracy: Method-derived outcomes and practitioner interpretations.

Recent research observed 92% accuracy for age-at-death estimations by U.S. forensic anthropologists. The present study compares this case report level accuracy to method level accuracy for the most commonly used methods in U.S. casework, drawing from the Forensic Anthropology Database for Assessing Methods Accuracy (FADAMA). Method application rate (i.e., how often a method is used in casework) was analyzed for n = 641 cases and identified 15 methods with an application rate >45 cases, and the present study focused further analyses on these 15 methods. Of the 15, only four yielded accuracies greater than or equal to the 92% documented for case-report level accuracy. The other 11 methods produced accuracy rates ranging from 54% to 91%, with six of these below 70% This disconnect between highly accurate age estimations at the case report level compared to the poor performance at method level suggests that practitioner interpretation and synthesis of the methods' outcomes is a critical step for increasing the accuracy rates of the age estimations as reported on the final case report. This inference was further supported by the study's results which indicated that practitioner interpretations of frequently used method combinations improve accuracy and age range width of age estimation. The study also performed a Fisher's Exact test to assess whether case report-level accuracy differed with the number of aging methods used in a case, and found no significant differences.

Utilizing augmented reality for reconstruction of fractured, fragmented and damaged craniofacial remains in forensic anthropology.

Forensic anthropologists are often confronted with human remains that have been damaged due to trauma, fire, or postmortem taphonomic alteration, frequently resulting in the fracture and fragmentation of skeletal elements. The augmented reality (AR) technology introduced in this paper builds on familiar 3D visualization methods and utilizes them to make three dimensional holographic meshes of skeletal fragments that can be manipulated, tagged, and examined by the user. Here, CT scans, neural radiance fields (NeRF) artificial intelligence software, and Unreal Engine production software are utilized to construct a three-dimensional holographic image that can be manipulated with HoloLens™ technology to analyze the fracture margin and reconstruct craniofacial elements without causing damage to fragile remains via excessive handling. This allows forensic anthropologists a means of assessing aspects of the biological profile and traumatic injuries without risking further damage to the skeleton. It can also be utilized by students and professional anthropologists to practice refitting before reconstructing craniofacial fragments if refitting is necessary. Additionally, the holographic images can be used to explain complicated concepts in a courtroom without the emotional response related to using bony elements as courtroom exhibits.

The forensic imaging technique of age progression used within missing people cases: The Italian Missing Children association realizing age progression for Missing Child Kenya.

The age progression technique allows to update identification photos of individuals who have been missing for years. This method is based on the study of the facial variation and on the dynamics of facial growth. Knowledge about changes in the distribution of facial fat and the tone of the cartilage allows realistic predictions of the facial appearance after many years. Beside these elements, age progression is also supported by similar characters between family members. This is why photos of the missing and family members are used to create an age progression, making the new identikit accurate. Non-profit associations are crucial for the dissemination of information on the problem of missing persons. In Italy, the Italian Missing Children association provides for free an age progression service with the support of forensic anthropology. With the activation of a protocol, consisting of guidelines, and a form for the request for age progression by family members, the Italian Missing Children has started a collaboration with Missing Child Kenya. It allowed to disseminate up-to-date photos of the presumed current appearance of the missing children in Kenya. Thus, in the present study some cases are reported, in which age progression technique was applied. The photos provided by Italian Missing Children were shown in video documentaries made by Missing Child Kenya, allowing to continue the dissemination of age progression photo during the Covid quarantines and to keep the population active in the search for the missing.

Facial soft-tissue thickness in children: A study of a CTBC Brazilian sample.

As an auxiliary method in the process of human identification, forensic facial approximation (FFA) is an important tool for identifying unknown human bodies whose remains do not present the necessary traceability to any antemortem data collection. Specific characteristics are necessary when addressing children aged between 6 and 10 years, who have little sexual differentiation and a mixed dentition. Due to the chronology of eruption of the permanent second molars in this population, it is not possible to measure facial soft-tissue thickness (FSTT) from specific landmarks such as supra and infra M2. The objective of this research was to report the method for measuring the average FSTT of 32 landmarks adapting the method for adults replacing the landmarks at the upper and lower second molars (Supra M2 and Infra M2) in children up to 10 years of age for a measurement using the deciduous second molars as reference. We found statistical differences for some points, considering the variables of age and sex, but with a maximum difference of 2 mm, which allows the use of a single FSTT table. The deciduous teeth can replace the reference of the thicknesses at the supra and infra M2 landmarks. In addition to the new FSTT data for children in Brazil, we concluded that the proposed adaptation to the deciduous M2 points can be applied to obtain soft-tissue data for 32 facial points.

Quantitative color analysis of burned bone to predict DNA quantity, quality, and genotyping success.

Badly burned skeletal remains are commonly submitted to forensic laboratories for victim identification via DNA analysis methods. Burned skeletal remains present many challenges for DNA analysis as they can contain low amounts of DNA which can also be damaged and degraded, resulting in partial or no STR profiles. Therefore, a simple, but effective screening method that identifies which samples may provide the most successful STR or mtDNA typing results for identification would enable forensic laboratories to save time, money, and resources. One metric that can be used and a screening method is the color of burned bone, as bone color changes with exposure to fire as temperature and length of exposure increase. This research developed a quantitative screening method based on the surface color of burned bone. The different visual bone colors (light brown, dark brown, black, gray, and white) were quantified using the Commission on Illumination L*a*b color space. These values were then compared to DNA yield, STR, and mtDNA profile completeness to identify whether the L*a*b values can predict genotyping success. A Bayesian network was constructed to determine the probability of STR typing success, given a set of L*a*b values. Results demonstrated that samples with an a* value greater than or equal to one and b* value greater than eight (light brown and dark brown burned samples) were the most predictive of STR typing success and mtDNA typing success. A decision tree for processing burned bones was constructed based on the color value thresholds.

[The experience of comparing reconstructions of the external appearance made on skulls with existing lifetime photographs]. / Opyt sopostavleniya rekonstruktsii vneshnego oblika, vypolnennykh po cherepam, s imeyushchimisya prizhiznennymi fotografiyami.

The conducted research is aimed at correcting the method of graphic reconstruction of the appearance based on the skull. The method is widely used in both anthropology and criminology. The Forensic Center of Ministry of Internal Affairs of Russia was sent the skulls for which there were lifetime photographs. The restoration of the appearance in the form of graphic reconstructions was carried out by students who completed the course of Anthropological reconstruction at the RSUH, under the guidance of Prof., head of the Laboratory E.V. Veselovskaya. Strictly after the restoration of the appearance was completed, lifetime photos were provided, on the basis of which the degree of similarity of the reconstruction with the original was assessed. The purpose of the experiment is to correct the method of graphic reconstruction of the appearance based on the skull and supplement it with new details. Anthropologists carried out gender and age determination of individuals for a more accurate representation of appearance. Based on the results of comparing lifetime photographic images with the performed reconstructions, it can bed that their overall satisfactory level of compliance is sufficient for correct identification. However, a number of inaccuracies have been identified. As a result, areas of the face have been identified that require further refinement of the method of anthropological reconstruction. So, the thickness, and especially the shape, of the lips turned out to be an unresolved problem. The size of the iris is an important physiognomic feature. It is recommended to clarify the definition of the skull of the lifetime physiognomic height of the face, the width of the nose and the distance between the nasolabial folds.

Comparing a common clavicle maturation-based age estimation method to ordinary regression analyses with quadratic and sex-specific interaction terms in adolescents.

Established methods of age estimation are based on correlating defined maturation stages of bony structures with tables representing the observed range of biological ages in the majority of cases. In this retrospective monocentric study in southwestern Germany, common age estimation methodology was assessed in n = 198 subjects at the age of 25 or younger by analyzing the influence of age, quadratic age, biological sex and age-sex interaction on the ossification stages of the medial epiphysis fugue. Three readers (ICC ≥ 0.81 for left/right side) evaluated routine care computed tomography images of the clavicle with a slice thickness of 1 mm. By using least square regression analyses, to determine the real biological age a quadratic function was determined corrected for the age estimated by established methods and sex (R2 = 0.6 each side), reducing the mean absolute error and root mean squared error in the age estimation of women (2.57 and 3.19) and men (2.57 and 3.47) to 1.54 and 1.82 for women, and 1.54 and 2.25 for men. In women, the medial clavicle epiphysis seem to fuse faster, which was particularly observable from approximately 18 years of age. Before that age, the estimation method was relatively close to the ideal correlation between assessed and real age. To conclude, the presented new method enables more precise age estimation in individuals and facilitates the determination and quantification of additional variables, quantifying their influence on the maturation of the medial clavicle epiphysis based on the established ossification stages.

Evaluating postcranial macromorphoscopic traits to estimate population variation among modern South Africans.

Population overlap and the variation within and among populations have been globally observed but is often difficult to quantify. To achieve this, numerous different methods need to be explored and validated to assist with the creation of an accurate biological profile. The current lack of databases for postcranial macromorphoscopic traits indicates the need to further investigate if the method can be employed repeatably in a forensic context. The current study aimed to assess the prevalence of eleven postcranial macromorphoscopic traits in a South African sample. A total of 271 postcrania of adult black, coloured, and white South Africans were assessed. The intra- and inter-observer agreement ranged from fair to almost perfect except for the accessory transverse foramen of C1, which had poor agreement between observers. Only seven traits differed significantly between at least two of the groups. Univariate and multivariate random forest models were created to test the positive predictive performance of the traits to classify population affinity. The classification accuracies for the univariate models ranged from 33.3% to 53.0% and ranged from 54.6% to 62.1% for the multivariate models. Based on the variable importance, the traits assessing spinous process bifurcation were the most discriminatory variables. The results indicate that the postcranial MMS approach does not outperform current methods employed to estimate population affinity. Further research needs to be done for the method to have practical applicability for medicolegal casework in South Africa.

Estimation of ancestry from cranial measurements based on MDCT data acquired in a Japanese and Western Australian population.

The estimation of ancestry is important not only towards establishing identity but also as a required precursor to facilitating the accurate estimation of other attributes such as sex, age at death, and stature. The present study aims to analyze morphological variation in the crania of Japanese and Western Australian individuals and test predictive models based on machine learning for their potential forensic application. The Japanese and Western Australian samples comprise computed tomography (CT) scans of 230 (111 female; 119 male) and 225 adult individuals (112 female; 113 male), respectively. A total of 18 measurements were calculated, and machine learning methods (random forest modeling, RFM; support vector machine, SVM) were used to classify ancestry. The two-way unisex model achieved an overall accuracy of 93.2% for RFM and 97.1% for SVM, respectively. The four-way sex and ancestry model demonstrated an overall classification accuracy of 84.0% for RFM and 93.0% for SVM. The sex-specific models were most accurate in the female samples (♀ 95.1% for RFM and 100% for SVM; ♂91.4% for RFM and 97.4% for SVM). Our findings suggest that cranial measurements acquired in CT images can be used to accurately classify Japanese and Western Australian individuals into their respective population. This is the first study to assess the feasibility of ancestry estimation using three-dimensional CT images of the skull.

Estimation of sex using dimensions around the metatarsal diaphyseal nutrient foramen: Application of discriminant function analysis and logistic regression models.

Sex estimation equations are population-specific, and a wider use of multiple bones to generate equations will increase the accuracy of sex estimation in forensic settings. The metatarsal bones have been used previously, however the dimensions around the diaphyseal nutrient foramen have not been utilised in sex estimation. The current study aimed to determine the utility of the dimensions around the nutrient foramen of metatarsal bones in estimating sex in the South Africans of European descent (SAED). Five measurements around the nutrient foramen were taken from a total of 876 metatarsal bones (first to fifth) from 186 individual skeletons (99 males, 87 females) obtained from the Raymond A. Dart Modern Skeletal Collection. Measurements subjected to direct and stepwise discriminant function (DFA) and logistic regression (LRA) analyses included total length, distance from proximal end to nutrient foramen, circumference, and mediolateral and dorsoplantar diameters at the level of the nutrient foramen. The original classification accuracies for multivariable functions of the stepwise and direct DFA ranged from 83.1-88.3% to 85.5-88.3%, respectively. The original classification accuracies for multivariable functions of the stepwise and direct LRA ranged from 83.3%-88.7% to 86.2%-88.3%, respectively. The cross-validation classifications showed a drop of 0-2.4% for DFA and 0.2-1.1% for LRA. The width measurements were better predictors of sex than length. The dimensions around the metatarsal bone nutrient foramen exhibit sexual dimorphism in the SAED. The generated DFA and LRA functions produced high average classification accuracies which are useful in sex estimation during forensic human identification.

An optimal skeletal element for DNA testing: Evaluation of DNA quantity and quality from various bone types in routine forensic practice.

For human identification, the quality and quantity of DNA must be sufficient for amplification and analysis. When DNA extraction from bone tissues and teeth is required, the optimal skeletal elements should be selected as samples for DNA extraction because DNA yield differs among elements. Recently, some studies have reported that a high quantity of high-quality DNA can be extracted from the small cancellous bones of the hands and feet. In this study, we evaluated the effectiveness of small cancellous bones in the human identification of skeletal remains in routine forensic genetic casework. Cancellous bones [phalanges, (meta)carpal bones, and (meta)tarsal bones)] and the cortical bones (femur and petrous bones) and teeth, which have generally been recommended as samples, were collected from the same individuals that needed identifying using DNA analysis in our laboratory. The quantity of DNA from small cancellous bones tended to be higher than that from cortical bones, and the quality from the former was as high as that from the latter. This study showed that in routine forensic casework, the small cancellous bones of the hands and feet should be actively selected as samples for DNA testing.

Technical Note: Individuals identified by radiographic comparison: A sample of demographics and the region of body used for identification in Clark County, Nevada, USA (2017-2020).

Radiographs regularly aid in identifications by comparing antemortem and postmortem images. The forensic community has widely accepted this method because radiographic images are low in cost, easily transferable, and generally believed to be uncomplicated to assess. However, there is a dearth of diverse, modern radiographic datasets as well as a deficiency in assessing population frequencies of nonmetric traits via radiographs. Further, radiographic comparisons, although typically required as a core competency of practicing forensic anthropologists, do not have standard training and education requirements. To understand the diversity and representation within an opportunistic dataset, we provide a case study of the demographics of decedents identified via radiographic comparison at the Clark County Office of the Coroner/Medical Examiner (CCOCME) in Las Vegas, NV, USA from 2017 to 2020. Additionally, we examined each region of the body used to make radiographic identifications. The sample was majority Caucasian and male, with a mean and median age at death of 64.9 years and 67.0 years, respectively. Our results indicated that this sample was not representative of the greater Clark County population. The most common body region used for comparisons was the chest, followed by the head and neck, pelvis, dentition, and the extremities. Thus, large generalizations made from these types of datasets must be implemented with caution due to the relative lack of diversity and representation. As well, current discussions regarding training and education of forensic anthropologists as they relate to radiographic comparisons are explored.

The influence of age on greater sciatic notch morphology: testing the Walker method in an Australian population.

Sex estimation is an integral aspect of a forensic biological profile. The pelvis, being the most dimorphic part of the skeleton, has been studied in considerable detail relative to morphological and metric variation. However, empirical data on the effect of age on pelvic morphology relative to sex-specific morphological variation is limited, especially in regard to the estimation of skeletal sex. This study assesses whether there are age-related differences in the distribution of the Walker (2005) morphological scores for the greater sciatic notch (GSN) in an Australian population. Three-dimensional volumetric reconstructions derived from multi-detector computed tomography (MDCT) scans of 567 pelves of 258 females and 309 males aged 18 to 96 years were scored following Walker (2005). Differences in score distributions and means by sex and age group were tested using Pearson's chi-squared test and ANOVA, respectively. The accuracy of sex estimates derived from logistic regression equations was explored using leave-one-out cross-validation. Significant differences were found in score distribution and means among age groups in females, but not in males. There was a tendency toward higher scores in older females. The overall sex estimation accuracy was 87.5%. When comparing age groups 18-49 and 70 + years, estimation accuracy decreased in females (99% vs. 91%), while the opposite was found for males (79% vs. 87%). These findings suggest that age affects GSN morphology. Higher mean scores in older females imply that, on average, the GSN becomes narrower with increasing age. It is thus recommended due consideration of estimated age when assessing sex based on the GSN in unidentified human remains.