Sex determination of human skeletal populations using latent profile analysis.

Accurately estimating biological sex from the human skeleton can be especially difficult for fragmentary or incomplete remains often encountered in bioarchaeological contexts. Where typical anatomically dimorphic skeletal regions are incomplete or absent, observers often take their best guess to classify biological sex. Latent profile analysis (LPA) is a mixture modeling technique which uses observed continuous data to estimate unobserved categorical group membership using posterior probabilities. In this study, sex is the latent variable (male and female are the two latent classes), and the indicator variables used here were eight standard linear measurements (long bone lengths, diaphyseal and articular breadths, and circumferences). Mplus (Muthén and Muthén: Mplus user's guide, 6th ed. Los Angeles: Muthén & Muthén, 2010) was used to obtain maximum likelihood estimates for latent class membership from a known sample of individuals from the forensic data bank (FDB) (Jantz and Moore-Jansen: Database for forensic anthropology in the United States 1962-1991, Ann Arbor, MI: Interuniversity Consortium for Political and Social Research, 2000) (n = 1,831), yielding 87% of correct classification for sex. Then, a simulation extracted 5,000 different random samples of 206 complete cases each from the FDB (these cases also had known sex). We then artificially imposed patterns of missing data similar to that observed in a poorly preserved bioarchaeological sample from Medieval Asturias, Spain (n = 206), and ran LPA on each sample. This tested the efficacy of LPA under extreme conditions of poor preservation (missing data, 42%). The simulation yielded an average of 82% accuracy, indicating that LPA is robust to large amounts of missing data when analyzing incomplete skeletons.

Forensic archeology as a high-impact practice.

High-impact practices (HIPs) are educational modalities that focus on experiential and deep learning to affect student success in higher education, particularly among students matriculating from historically underserved communities. HIPs are designed to provide students with the intellectual and practical skills to succeed in an increasingly unstable global world beyond college. Utilizing a private-public partnership forensic archeological contract project, this paper examines how this venture employed a HIP-based contractor model that hired students as a professional archeological field crew and provided them with a living wage, transportation, and room and board. It also provided students without the means to participate in international fieldwork with the wherewithal to do so, supporting underserved students and diversity, equity, inclusion, and belonging (DEIB) initiatives. Utilizing this HIP-based contract model resulted in greater student investment and collaboration in a fieldwork situation more akin to the real world, where students learned to solve problems, communicate, and network in an international setting, resulting in new opportunities, such as professional jobs, and academic projects and publications. The paid contractor model ensured students with limited resources could participate, broadening the type of student who can receive this type of training, expanding diversity in forensic anthropology. These models are not limited to forensic archeological fieldwork; they can also be applied to forensic anthropology laboratory projects. Utilizing HIPs and employing a more equitable contractor model contributes to student professionalization, strengthens professional prospects beyond the university, and contributes to DEIB initiatives, all of which benefit forensic anthropology as a subdiscipline.

A review of anatomical terminology for the hip bone.

Anatomists have been attempting to standardize anatomical terminology of the human body and in doing so created the Terminologia Anatomica as a standard language of anatomy. Despite developments such as the Terminologia Anatomica, a lack of consistency of anatomical terminology is still seen across and within disciplines. This study explores the variation in terminology for the hip bone through a literature review. In total, ten terms used to describe the hip bone were searched in PubMed, JSTOR, and EBSCO databases: "coxal bone," "hip bone," "innominate bone," "os coxa," "os coxae," "ossa coxa," "ossa coxae," "os innominatum," "os pelvicum," and "pelvic bone." Results found that the terms "hip bone" and "pelvic bone" were the most commonly used terms, with the most frequently used discipline being medicine. However, we argue against the use of these terms in favor of "coxal bone" or "innominate bone." "Hip bone" should be avoided due to its colloquial nature, and "pelvic bone" is not specific enough to the structure of the hip. Latin terms are often incorrectly conjugated (e.g., "os coxae"); therefore, the English equivalent should be used when possible. Regardless, standardization of anatomical terminology should be adopted through consensus by practitioners, researchers, and stakeholders.

Evaluating expertise in forensic anthropology.

The medicolegal system relies on the ability of experts and non-experts alike to make judgments about expertise and use those judgments to reach consequential decisions. Given the lack of standard criteria, mandatory certification, or licensure for establishing expertise required to practice forensic anthropology and testify as an expert witness, we sought to understand how individuals assess and identify expertise in forensic anthropology by using a social science tool called the Imitation Game. This tool assesses immersion in a specific area of study via discourse, with the premise that some individuals lacking expertise themselves imitate or attempt to pass as experts. For this project we recruited volunteers with varying expertise in forensic anthropology to participate in interviews which asked questions about the practice and structure of the discipline. Those interviews were transcribed, anonymized, and evaluated by other recruited individuals with varying expertise in forensic anthropology. Results found that judges who were experts in forensic anthropology performed better than non-expert judges in determining who was not an expert in forensic anthropology based on their anonymized responses; however, nearly half of the non-experts were still able to pass as experts in forensic anthropology. The difficulties in assessing expertise based on discourse interactions demonstrates the value and need for well-defined credentials and mandatory certification to practice forensic anthropology. This study demonstrates that accurately identifying expertise in forensic anthropology may be challenging for both experts and non-experts, especially when relying solely on interactional expertise rather than formal assessments of competency which directly elucidate contributory expertise.

Investigating identification disparities in forensic anthropology casework.

Forensic anthropology is shifting to reflect on the impact of its practices within the criminal justice context in important ways. Here, we contribute to this essential work by examining how decedent demographics as well as estimations of biological profile components are related to identification trends in forensic anthropology cases. The study uses data from more than 1,200 identified and unidentified forensic anthropology cases from three agencies (together representing a nation-wide sample). We found the following: i) multivariate analyses indicated that decedent sex, age, and race and/or ethnicity are not related to case identification rates in the pooled United States sample, ii) when identification rate differences do occur, they appear to be smaller effects, more agency-specific, and/or related to the context of a particular agency, iii) for the agency-specific sample with available data, there was no consistent evidence for a discrepancy in the duration of an identification investigation based on a decedent's sex, age, or race and/or ethnicity, iv) forensic anthropological estimations of sex, age, and ancestry can improve the odds of identification for decedents, although these are small effects, and v) reporting an ancestry estimation does not appear to impact decedent race representation among resolved unidentified person cases. Although previous studies have identified demographic discrepancies in other areas of the criminal justice system, the results presented here suggest that decedent demographic estimation practices by forensic anthropologists in general do not appear to be related to discrepancies in identification trends, but more research is needed to examine whether these findings hold. Contextual factors and practices specific to each investigative agency likely contribute to identification trends.

How Do Drugs Affect the Skeleton? Implications for Forensic Anthropology.

Forensic anthropologists rely on a number of parameters when analyzing human skeletal remains to assist in the identification of the deceased, predominantly age-at-death, sex, stature, ancestry or population affinity, and any unique identifying features. During the examination of human remains, it is important to be aware that the skeletal features considered when applying anthropological methods may be influenced and modified by a number of factors, and particular to this article, prescription drugs (including medical and non-medical use) and other commonly used drugs. In view of this, this paper aims to review the medical, clinical and pharmacological literature to enable an assessment of those drug groups that as side effects have the potential to have an adverse effect on the skeleton, and explore whether or not they can influence the estimation of age-at-death, sex and other indicators of the biological profile. Moreover, it may be that the observation of certain alterations or inconsistencies in the skeleton may relate to the use of drugs or medication, and this in turn may help narrow down the list of missing persons to which a set of human remains could belong. The information gathered from the clinical and medical literature has been extracted with a forensic anthropological perspective and provides an awareness on how several drugs, such as opioids, cocaine, corticosteroids, non-steroidal anti-inflammatory drugs, alcohol, tobacco and others have notable effects on bone. Through different mechanisms, drugs can alter bone mineral density, causing osteopenia, osteoporosis, increase the risk of fractures, osteonecrosis, and oral changes. Not much has been written on the influence of drugs on the skeleton from the forensic anthropological practitioner perspective; and this review, in spite of its limitations and the requirement of further research, aims to investigate the current knowledge of the possible effects of both prescription and recreational drugs on bones, contributing to providing a better awareness in forensic anthropological practice and assisting in the identification process of the deceased.

Forensic Anthropology as a Discipline.

This paper explores the current state of forensic anthropology in the United States as a distinct discipline. Forensic anthropology has become increasingly specialized and the need for strengthened professionalization is becoming paramount. This includes a need for clearly defined qualifications, training, standards of practice, certification processes, and ethical guidelines. Within this discussion, the concept of expertise is explored in relation to professionalization and practice, as both bioarchaeology and forensic anthropology have different areas of specialist knowledge, and therefore unique expertise. As working outside one's area of expertise is an ethical violation, it is important for professional organizations to outline requisite qualifications, develop standards and best practice guidelines, and enforce robust preventive ethical codes in order to serve both their professional members and relevant stakeholders.

Scientific integrity in the forensic sciences: Consumerism, conflicts of interest, and transparency.

The goal of this paper is to discuss scientific integrity, consumerism, conflicts of interest, and transparency within the context of forensic science. Forensic scientists play crucial roles within the legal system and are constantly under various pressures when performing analytical work, generating reports based on their analyses, or testifying to the content of these reports. Maintaining the scientific integrity of these actions is paramount to supporting a functional legal system and the practice of good science. Our goal is to discuss the importance of scientific integrity as well as the factors it may compromise, so that forensic practitioners may be better equipped to recognize and avoid conflicts of interest when they arise. In this discussion we define terms, concepts, and professional relationships as well as present three case studies to contextualize these ideas.

Investigations Into Age-related Changes in the Human Mandible.

While changes in mandibular shape over time are not widely recognized by skeletal biologists, mandibular remodeling and associated changes in gross morphology may result from a number of causes related to mechanical stress such as antemortem tooth loss, changes in bite force, or alterations of masticatory performance. This study investigated the relationship between age-related changes and antemortem tooth loss in adult humans via dry bone measurements. This study examined 10 standard mandibular measurements as well as individual antemortem tooth loss scores using the Eichner Index from a total of 319 female and male individuals with ages ranging from 16 to 99 years. Results indicate that few mandibular measurements exhibited age-related changes, and most were affected by antemortem tooth loss.

Beyond Taphonomy: Exploring Craniometric Variation Among Anatomical Material.

Anatomical crania are occasionally encountered in forensic anthropology laboratories when that material is mistaken for forensically significant human remains. Using craniometric analyses and statistical measures of sample homogeneity, we determine whether anatomical material can be described as a single, homogenous group or as a diverse mix of populations. Twenty-one interlandmark distances were collected from 85 anatomical preparations. Distance measures were calculated between all pairs using a pooled within-sample variance/covariance matrix and then subjected to a Defrise-Gussenhoven test between each paired distance to test whether each pair was drawn randomly from the same population. In the Defrise-Gussenhoven analysis, twenty-two percent (n = 66) of the 300 pairwise combinations were significant at the 0.05 level or below. The level of homogeneity suggests a majority of that material originated from the subcontinent of India or West Asia. Therefore, anatomical material can be viewed as a moderately homogenous group, but with a shared taphonomic history.

Fracture characteristics of entrapped head impacts versus controlled head drops in infant porcine specimens.

In many forensic cases, the job of forensic pathologists and anthropologists is to determine whether pediatric death is due to an abusive act or an accidental fall. The goal of this study was to compare the cranial fracture patterns generated on the parietal bone of a developing, infant porcine (pig, Sus scrofa) model by a controlled energy head drop onto a plate versus previous data generated by blunt force impact at the same energy onto the head constrained to a plate. The results showed that blunt force impacts on a head constrained to a rigid plate produces more fracture, but the same general pattern, as that for a head dropped onto the plate with the same level of impact energy. The study suggests that head constraint may be an important factor to consider in the evaluation of death causation for blunt force impacts to the pediatric skull.

Current practices by forensic anthropologists in adult skeletal age estimation.

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

Patterns of trauma induced by motorboat and ferry propellers as illustrated by three known cases from Rhode Island.

Understanding patterns of trauma is important to determining cause and manner of death. A thorough evaluation of taphonomy, trauma, and bone fracture mechanisms is necessary to reconstruct the circumstances of the death. This study examines the skeletal trauma caused by boat propeller strikes in terms of wound characteristics and location based on three cases from Rhode Island. These case studies review the traumatic characteristics caused by propeller injuries and highlight the anatomic regions most likely to sustain skeletal trauma. With this information, investigators may be able to identify propeller trauma even in severely decomposed remains. The discussion of boat propeller trauma also raises issues regarding how forensic anthropologists and forensic pathologists classify trauma (specifically blunt force vs. sharp) and highlights semantic issues arising in trauma classification. The study also discusses why these propeller cases should be classified as blunt trauma rather than sharp or chop/hack trauma. Ultimately, the authors urge consistency and communication between pathologist and forensic anthropologists performing trauma analyses.

Fracture patterns on the infant porcine skull following severe blunt impact.

The objective of this study was to document patterns of fracture on infant porcine skulls aged 2-28 days (n = 57) because of a single, high energy blunt impact to the parietal bone with rigid (nondeformable) and compliant (deformable) interfaces. Fracture patterns were mapped using Geographic Information System software. For the same generated impact force, the rigid interface produced more fractures than the compliant interface for all ages. This study also showed that this increased level of impact energy versus an earlier study using a lower energy resulted in new sites of fracture initiation and also caused previously defined fractures that propagate into an adjacent bone. Several unique characteristics of bone and diastatic fracture were documented as a function of specimen age, impact energy, and interface. These data describe some baseline characteristics of skull fracture using an animal model that may help guide future studies from forensic case files.

The utility of the Samworth and Gowland age-at-death "look-up" tables in forensic anthropology.

Accurate age-at-death estimates are crucial to forensic anthropologists when onstructing biological profiles aimed at narrowing a missing-persons list and to allow for timely and efficient identification of an unknown victim. The present contribution evaluates the utility of three new age-at-death estimation techniques recently proposed by Samworth and Gowland (2007). Results indicate that, in the samples under study, the Samworth and Gowland estimates from the pubic symphysis and auricular surface perform similar to alternate phase methods. The combined method does not appear to further enhance either the precision or the accuracy of the single pubic symphysis age-at-death estimate. In conclusion, these new methods seem to be more robust to distribution deviations than originally proposed by Samworth and Gowland (2007). They are therefore suitable for immediate and reliable forensic usage in the United States and worthy of further research for their use in North American forensic contexts.