Average thickness of the bones of the human neurocranium: development of reference measurements to assist with blunt force trauma interpretations.

The accurate interpretation of a blunt force head injury relies on an understanding of the case circumstances (extrinsic variables) and anatomical details of the individual (intrinsic variables). Whilst it is often possible to account for many of these variables, the intrinsic variable of neurocranial thickness is difficult to account for as data for what constitutes 'normal' thickness is limited. The aim of this study was to investigate the effects of age, sex and ancestry on neurocranial thickness, and develop reference ranges for average neurocranial thickness in the context of those biological variables. Thickness (mm) was measured at 20 points across the frontal, left and right parietals, left and right temporals and occipital bones. Measurements were taken from post-mortem computed tomography scans of 604 individuals. Inferential statistics assessed how age, sex and ancestry affected thickness and descriptive statistics established thickness means. Mean thickness ranged from 2.11 mm (temporal squama) to 19.19 mm (petrous portion). Significant differences were noted in thickness of the frontal and temporal bones when age was considered, all bones when sex was considered and the, right parietal, left and right temporal and occipital bones when ancestry was considered. Furthermore, significant interactions in thickness were seen between age and sex in the frontal bone, ancestry and age in the temporal bone, ancestry and sex in the temporal bone, and age, sex and ancestry in the occipital bone. Given the assorted influence of the biological variables, reference measurement ranges for average thickness incorporated these variables. Such reference measurements allow forensic practitioners to identify when a neurocranial bone is of normal, or abnormal, thickness.

Human identification: a review of methods employed within an Australian coronial death investigation system.

Whilst many identification methods have been widely described and discussed in the literature, and considered in disaster and humanitarian contexts, there has been limited reporting and evaluation of the identification methods used in domestic medico-legal death investigation contexts. The aim of this study was to evaluate the identification methods utilised at the Victorian Institute of Forensic Medicine (VIFM), which forms part of a coronial medico-legal death investigation system. The method of identification and time taken to complete the identification were reviewed for all cases admitted to the VIFM over a five-year period from 1 July 2015 to 30 June 2020. The majority, 91%, of individuals admitted to the VIFM were visually identified. The remaining 9% of cases required identification by primary methods (i.e. fingerprints, DNA or dental) or, when those methods were not possible, by secondary methods (i.e. circumstantial). Visual identifications were the timeliest, taking an average of 1.5 days, whilst primary identification methods required an average of 5 days to complete. The triaging of identification methods, dependent on the case context, body preservation, availability of ante-mortem data, legal requirements and admissibility of the method, are determined by identification coordinators within the Human Identification Service (HIS) to ensure the most appropriate and timely method is employed. This review of human identification methods provides the foundation for future analyses to compare workflow processes and improve identification methods utilised in domestic medico-legal contexts.

Lack of biological mortality bias in the timing of dental formation in contemporary children: Implications for the study of past populations.

OBJECTIVES: Biological mortality bias is the idea that individuals who perish (non-survivors) are biologically distinct from those who survive (survivors). If biological mortality bias is large enough, bioarchaeological studies of nonsurvivors (skeletal samples) cannot accurately represent the experiences of the survivors of that population. This effect is particularly problematic for the study of juvenile individuals, as growth is particularly sensitive to environmental insults. In this study, we test whether biological mortality bias exists in one dimension of growth, namely dental development. MATERIALS AND METHODS: Postmortem computed tomography scans of 206 children aged 12 years and younger at death were collected from two institutions in the United States and Australia. The sample was separated into children dying from natural causes as proxies for non-survivors and from accidental causes as proxies for survivors. Differences in the timing of dental development were assessed using sequential logistic regressions between dental formation stages and residual analysis of dental minus chronological age. RESULTS: No consistent delay in age of attainment of dental stages was documented between survivors and non-survivors. Delays between survivors and non-survivors in dental relative to chronological age were greatest for infants, and were greater for females than for males. DISCUSSION: Lack of biological mortality bias in dental development reinforces confidence in juvenile age estimates and therefore in skeletal growth profiles and growth studies. As dental development is known to be less environmentally sensitive than skeletal growth and development, further studies should examine biological mortality bias in long bone length.

Fatal falls involving stairs: an anthropological analysis of skeletal trauma.

The skeletal blunt force trauma resulting from fatal falls involving stairs is complex. There are countless ways an individual may fall when stairs are involved, and thus a variety of ways the skeleton may fracture. Therefore anecdotally, it may be said that there is no specific skeletal trauma characteristic of this fall type. In order to scientifically investigate this anecdotal understanding, this study provides a detailed investigation of the skeletal fracture patterns and morphologies resulting from fatal falls involving stairs. Skeletal trauma was analyzed using the full-body postmortem computed tomography scans of 57 individuals who died from a fall involving stairs. Trauma was examined in the context of the variables that potentially influence how an individual falls (i.e. sex, age, body mass index, number of stairs involved, psychoactive drugs, pre-existing conditions, landing surface and manner of the fall) using logistic regression. Skeletal trauma primarily occurred in the axial skeleton. An analysis of fracture patterns showed the cranial base was less likely to fracture in younger individuals and the cervical vertebrae were more likely to fracture in falls that involved more than half a flight of stairs. A total of 56 fracture morphologies were identified. Of these, diastatic fractures were less likely to occur in older individuals. Findings indicate that there are skeletal fracture patterns and morphologies characteristic of a fatal fall involving stairs.

Managing large volume data sets in the process of identifying missing persons: Contributions from the International Commission on Missing Persons.

The process of locating and identifying missing persons presents a complex challenge that hinges on the collection and comparison of diverse data sets. This commentary offers an overview of some of the difficulties and considerations associated with data management in the context of large-scale missing person identifications. Such complexities include the uniqueness of each disaster event, the response time to the event, the variable quality and quantity of data, and the involvement of numerous stakeholders, all of which contribute to the intricacies of data management. In addition, the paramount considerations of privacy and ethical standards further compound these challenges, especially when dealing with sensitive information such as genetic data. This commentary describes the integrated Data Management System (iDMS) developed by the International Commission on Missing Persons (ICMP) as one example of a comprehensive, freely available solution for data collection, storage, protection, and analysis in missing person cases. The various advantages of the system are discussed, including the system's interoperability among the diverse array of stakeholders involved. While the iDMS streamlines data management processes and therefore represents a significant advancement in the field of missing person identification, it is concluded that the pending issue extends beyond the software tools to encompass the lack of political will among stakeholders to collaborate there remains a pressing need for all stakeholders involved in the identification process to commit to a mechanism that facilitates compatibility and interoperability if different tools are used in disaster victim identification (DVI) scenarios.

Radiocarbon dating as tool to assist in triaging cases of unidentified human remains in Victoria, Australia: A case series.

In cases where human remains are unidentified because there is no initial identification hypothesis, limited contextual information, and/or poor preservation, radiocarbon (14 C) dating may be a useful tool to further assist with identification. Through measuring the amount of 14 C remaining in organic material, such as bone, teeth, nail, or hair, radiocarbon dating may provide an estimated year of birth and year of death for a deceased person. This information, may assist in, establishing whether a case of unidentified human remains (UHR) is actually of medicolegal significance and therefore, requires forensic investigation and identification. This case series highlights the application of 14 C dating to seven of the 132 UHR cases in Victoria, Australia. Cortical bone was sampled from each case and the level of 14 C was measured to provide an estimated year of death. Four of the seven cases analyzed contained the levels of 14 C consistent with an archeological timeframe, one contained a level of 14 C consistent with a modern (i.e., of medicolegal significance) timeframe, and the results for the remaining two samples were inconclusive. Applying this technique not only reduced the number of UHR cases in Victoria but also has investigative, cultural, and practical implications for medicolegal casework in general.

Not so simple: Understanding the complexities of establishing identity for cases of unidentified human remains in an Australian medico-legal system.

Discussions regarding the importance and complexities associated with the identification of deceased persons have typically focused on disaster or humanitarian contexts where there has been large scale loss of life. In contrast, identification efforts for unidentified human remains (UHR) cases in routine domestic casework contexts have received relatively little attention. The aim of this paper was to present the situation regarding the count of UHR cases in the state of Victoria, Australia, dating between 1960 and 2020, and to provide a constructively critical appraisal of the factors that have, and continue to, hinder their identification. Over the six decades a total of 132 coronial cases remained unidentified; an average of 2-3 cases per annum. For each case, the preservation of the remains, geographical location of where they were recovered from, primary (fingerprints, dental, DNA) and secondary identification methods that had been employed, potential for additional identification testing and current curation of the remains, were recorded. The difficulty with providing a "total count" of UHR cases is discussed, as well as the ways in which preservation, availability of identification methods, changes in policies and procedures, record management, changes in practice and advancements in technology, have impacted the identification process. This paper demonstrates the complexity of the investigation of UHR cases, and why individuals continue to remain unidentified in 2021.

Exploring the use of machine learning for the assessment of skeletal fracture morphology and differentiation between impact mechanisms: A pilot study.

Analyzing and interpreting traumatic injuries is a fundamental aspect of routine forensic case work. As the human skeleton can be impacted through a combination of loading mechanisms and varying impact energies, the analysis and interpretation of skeletal trauma can be complex. Therefore, it is imperative that the reliability of techniques used for analysis are well-established. There is growing interest in machine learning (ML) in medicine (especially radiology) regarding the use of image classification (a subset of ML) to categorize and predict classes of medical images. Therefore, the feasibility of using image classification for skeletal trauma analysis should be explored for its benefits to forensic pathology and anthropology. The method explored in this paper examined the potential for machine learning, using three dimensional (3D) convolutional neural networks (CNNs), to assess whether morphological features of skeletal trauma to the femur can be used to differentiate between impact mechanisms within a forensic population. The objective of this study was to assess if morphological differences in femoral fractures seen in post-mortem-computed tomographic images (PMCT) could be categorized according to mechanism, specifically horizontal impacts resulting from pedestrian motor vehicle impacts (PMVIs) and vertical impact s resulting from high impact falls. Final model results indicated an accuracy between 69.95%-72.86% and 63.08%-66.24% validation. Although these results mean the method could not be practically used in its current form, as a proof of concept, there is potential for it to be developed as a tool to assist in classifying complex fracture states.

The issues and complexities of establishing methodologies to differentiate between vertical and horizontal impact mechanisms in the analysis of skeletal trauma: An introductory femoral test.

Understanding skeletal trauma characteristics is fundamental for the examination and interpretation of blunt force trauma (BFT). BFT is the most complex type of trauma to interpret based on the analysis of skeletal fractures alone, with comminuted fractures presenting additional complications to assess and interpret. Considerable variation exists within each type of BFT injury dependent on direction, magnitude of force, plus a myriad of biological/environmental factors. Given the complex processes governing the nature of BFT skeletal injuries determining whether differences between impact mechanisms and skeletal trauma can be quantified requires investigation. AIM: this study aims to determine the feasibility of quantifying outcomes between two separate loading conditions by using a formula created from transformed variables recorded from specific trauma cases involving BFT to the femur. METHODOLOGY: Displacement, comminution, and femoral midshaft area data were recorded from full body postmortem computed tomography scans of 103 individuals (males, mean age 42.5, and females, mean age 48.9) where cause of death was the result of rapid horizontal deceleration impact events (pedestrian motor vehicular accidents, n = 59) and vertical (>3-metre falls, n = 44). These measurements were standardised and transformed into a continuous variable. Independent t-tests, binary logistic regression and K Nearest- Neighbours (KNN) were used to analyse the data. RESULTS: The standardised values showed mean group differences between falls (9.62) and pedestrian motor vehicular impacts (pedestrian MVAs) (9.53), however, these results were not statistically significant. The results indicate that similarities in variance between types of trauma outcomes and impact mechanisms demonstrate low equivalency (samples have limited differences), and the overall limitations in relying on using single elements to explain complex skeletal trauma outcomes.

Analyzing the outcomes of skeletal trauma within a forensic population: Potential issues and implications in inferential modeling of blunt force trauma.

Analyzing complex skeletal trauma can present a challenge for forensic practitioners to reliably determine the causes and circumstances of traumatic injury. The forensic value of skeletal fracture pattern analysis can be diminished due to obscuration and similarity between injuries associated with various impact mechanisms (e.g., vertical vs horizontal blunt force) and can provide issues when questions arise surrounding circumstances of traumatic injuries. Using the Python coding language, code was written that segments traumatized regions of interest from post-mortem computed tomography (PMCT) scans, allowing the user to calculate percentage of fragmentation in the context of extreme trauma events. Using cases of known trauma which resulted in fragmentation of the femur, the objective was to assess if there were statistical differences in the fragmentation resulting from horizontal pedestrian motor vehicle impacts (PMVIs; n = 44) compared to vertical high impact falls (>3 m; n = 41). Results indicated that percentage differences between the PMVI group and high impact falls group were statistically significant. Although it was possible to develop a standardized method that records fragmentation, and results were significant in distinguishing between the two groups, the outcomes of the data follow an exponential distribution which has implications for how skeletal trauma is modeled.

Providing a Forensic Expert Opinion on the "Degree of Force": Evidentiary Considerations.

Forensic pathologists and anthropologists are often asked in court for an opinion about the degree of force required to cause a specific injury. This paper examines and discusses the concept of 'degree of force' and why it is considered a pertinent issue in legal proceedings. This discussion identifies the implicit assumptions that often underpin questions about the 'degree of force'. The current knowledge base for opinions on the degree of force is then provided by means of a literature review. A critical appraisal of this literature shows that much of the results from experimental research is of limited value in routine casework. An alternative approach to addressing the issue is provided through a discussion of the application of Bayes' theorem, also called the likelihood ratio framework. It is argued that the use of this framework makes it possible for an expert to provide relevant and specific evidence, whilst maintaining the boundaries of their field of expertise.

Detecting grave sites from surface anomalies: A longitudinal study in an Australian woodland.

Forensic investigations of single and mass graves often use surface anomalies, including changes to soil and vegetation conditions, to identify potential grave locations. Though numerous resources describe surface anomalies in grave detection, few studies formally investigate the rate at which the surface anomalies return to a natural state; hence, the period the grave is detectable to observers. Understanding these processes can provide guidance as to when ground searches will be an effective strategy for locating graves. We studied three experimental graves and control plots in woodland at the Australian Facility for Taphonomic Experimental Research (Sydney, Australia) to monitor the rate at which surface anomalies change following disturbance. After three years, vegetation cover on all grave sites and control plots had steadily increased but remained substantially less than undisturbed surroundings. Soil anomalies (depressions and cracking) were more pronounced at larger grave sites versus the smaller grave and controls, with leaf litterfall rendering smaller graves difficult to detect beyond 20 months. Similar results were observed in two concurrent burial studies, except where accelerated revegetation appeared to be influenced by mummified remains. Extreme weather events such as heatwaves and heavy rainfall may prolong the detection window for grave sites by hindering vegetation establishment. Observation of grave-indicator vegetation, which exhibited abnormally strong growth 10 months after commencement, suggests that different surface anomalies may have different detection windows. Our findings are environment-specific, but the concepts are applicable globally.

Evaluating the evidentiary value of the analysis of skeletal trauma in forensic research: A review of research and practice.

Understanding bone trauma characteristics is a fundamental component of forensic investigations that can assist in understanding the nature of blunt trauma related deaths. The variation of each blunt force trauma (BFT) injury is dependent on a magnitude of factors including, age, sex, health, angle of impact, impact mechanism, impact force and clothing, making BFT one of the more difficult area of trauma to interpret solely based on skeletal fractures. A detailed literature review was performed to assess the value and scientific rigour of the current research in forensic anthropology, forensic pathology and biomechanics that attempts to provide an objective framework in which forensic practitioners can assess and interpret BFT injuries. Four areas of research which investigate the analysis of BFT are examined. These included research involving experiments on animal models; experiments on human models (and synthetic models); computer modelling, and research/publications including 'mild', 'moderate' and 'severe' as descriptions of impact force, resulting from trauma. Also briefly discussed is how BFT research is framed within medicolegal contexts. While many published works have contributed to the understanding of the biomechanics of BFT, more research that can provide an objective means to accurately assess and interpret BFT injures is required.

A Review of Bomb Pulse Dating and its Use in the Investigation of Unidentified Human Remains.

In cases where there is limited antemortem information, the examination of unidentified human remains as part of the investigation of long-term missing person's cases is a complex endeavor and consequently requires a multidisciplinary approach. Bomb pulse dating, which involves the analysis and interpretation of 14C concentration, is one technique that may assist in these investigations by providing an estimate of year of birth and year of death. This review examines the technique of bomb pulse dating and its use in the identification of differentially preserved unknown human remains. Research and case studies implementing bomb pulse dating have predominantly been undertaken in the Northern Hemisphere and have demonstrated reliable and accurate results. Limitations were, however, identified throughout the literature. These included the small sample sizes used in previous research/case studies which impacted on the statistical significance of the findings, as well as technique-specific issues. Such limitations highlight the need for future research.

Disaster victim identification operations with fragmented, burnt, or commingled remains: experience-based recommendations.

Human-made and natural disasters can result in severely fragmented, compromised, and commingled human remains. The related disaster victim identification (DVI) operations are invariably challenging, with the state of the remains potentially precluding some identifications. Practitioners involved in these DVI operations will routinely face logistical, practical, and ethical challenges. This review provides information and guidance derived from first-hand experiences to individuals tasked with managing DVI operations with fragmented human remains. We outline several key issues that should be addressed during disaster preparedness planning and at the outset of an operation, when incident-specific strategies are developed. Specific challenges during recovery and examination of fragmented remains are addressed, highlighting the importance of experienced specialists at the scene and in the mortuary. DNA sample selection and sampling techniques are reviewed, as well as downstream effects of commingling and contamination, which can complicate reconciliation and emphasise the need for rigorous quality control. We also touch on issues that may arise during communication with families. While recommendations are provided, they are not intended as proscriptive policy but rather as an addition to the general recommendations given in the International Criminal Police Organization (INTERPOL) DVI Guide, to inform preparative discussions between government officials, judiciary, police, and forensic specialists.Key pointsA DVI operation for an incident characterised by many fragmented and otherwise compromised human remains poses specific challenges that may prolong and complicate identifications.Specialists should be consulted at the outset to address key issues related to the aim and extent of the operation.Specialist expertise in handling compromised human remains is indispensable at the scene, in the mortuary, during reconciliation, and for quality control.Continuous consultation between representatives from government, the judiciary, law enforcement, the media, and various forensic specialists will prevent unnecessary delay and facilitate accurate and timely communication.

An Assessment of the Skeletal Fracture Patterns Resulting from Fatal High (˃3 m) Free Falls.

The injury patterns resulting from fatal high (˃3 m) free falls have previously been documented in clinical and medico-legal contexts; however, details relating specifically to the skeletal blunt force trauma (BFT) have been limited. This study aimed to augment what is known of the skeletal fracture patterns resulting from fatal high free falls. Skeletal trauma was analyzed from full-body postmortem computed tomography scans of 95 individuals who died following a high free fall. Fracture patterns were documented using the five general anatomical regions, axial and appendicular regions, and postcranial unilateral and bilateral regions. Patterns were analyzed in the context of the extrinsic and intrinsic variables that may influence fractures using multiple logistic regression. Fracture patterns involved all aspects of the skeleton, with 98.9% exhibiting polytrauma, and were influenced primarily by the height fallen, manner of death, and landing surface. This improved understanding of fracture patterns will augment anthropological interpretations of the mechanism of BFT in cases of suspected high falls.

The role of forensic anthropology in disaster victim identification (DVI): recent developments and future prospects.

Forensic anthropological knowledge has been used in disaster victim identification (DVI) for over a century, but over the past decades, there have been a number of disaster events which have seen an increasing role for the forensic anthropologist. The experiences gained from some of the latest DVI operations have provided valuable lessons that have had an effect on the role and perceived value of the forensic anthropologist as part of the team managing the DVI process. This paper provides an overview of the ways in which forensic anthropologists may contribute to DVI with emphasis on how recent experiences and developments in forensic anthropology have augmented these contributions. Consequently, this paper reviews the value of forensic anthropological expertise at the disaster scene and in the mortuary, and discusses the way in which forensic anthropologists may use imaging in DVI efforts. Tissue-sampling strategies for DNA analysis, especially in the case of disasters with a large amount of fragmented remains, are also discussed. Additionally, consideration is given to the identification of survivors; the statistical basis of identification; the challenges related to some specific disaster scenarios; and education and training. Although forensic anthropologists can play a valuable role in different phases of a DVI operation, they never practice in isolation. The DVI process requires a multidisciplinary approach and, therefore, has a close collaboration with a range of forensic specialists.

An Anthropological Examination of the Types of Skeletal Fractures Resulting from Fatal High (˃3 m) Free Falls.

Fatal falls from heights (˃3 m) often result in blunt force trauma (BFT) to the skeleton. The fracture patterns that result from this BFT mechanism are well understood in forensic anthropology and forensic pathology; however, details of the specific types of fractures that result remain poorly documented. The aim of this study was to provide a detailed examination of the types of fractures that may result from fatal high falls. Fractures were recorded from 95 full-body postmortem computed tomography scans of individuals known to have died from a high fall. Trauma was then analyzed taking into account the extrinsic and intrinsic variables known to influence a fall using multiple logistic regression. A total of 339 types of fractures were classified, of which 16 were significantly associated with this BFT mechanism. Classified fracture types will augment anthropological interpretations of the circumstances of death from BFT in cases of suspected high falls.

Using PMCT of Individuals of Known Age to Test the Suchey-Brooks Method of Aging in Victoria, Australia.

The estimation of an individual's age at death plays a critical role in the investigation of unidentified human remains. The Suchey-Brooks method, which involves the analysis of degenerative morphological changes in the pubic symphysis, is currently widely used to estimate age in adults. This study tested the applicability of the Suchey-Brooks method on a contemporary adult Australian (Victorian) subpopulation by observing three-dimensional volume-rendered postmortem computed tomographic (PMCT) reconstructions of the pubic symphysis of 204 individuals aged 15-100 years. Results showed the method was reliable for females (85% correct allocations) but not for males (67% correct allocations). It is therefore recommended that extreme caution be used when applying the Suchey-Brooks method for estimating age at death of an individual in this subpopulation from PMCT images. The results suggest further investigation into alternate age estimation methods is required.