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SISTERS BUT NOT IDENTICAL TWINS: SOME CAUTIONARY NOTES ON ADOPTING FORENSIC ANTHROPOLOGICAL METHODS IN BIOARCHAEOLOGY
Abstract
Age-at-death, sex, and stature estimation from adult human skeletal remains lie at the core of bioarchaeolog-ical and forensic anthropological research. Several methods have been proposed for such estimations, with almost all of them being developed using modern documented skeletal collections. Therefore, unavoidably bioarchaeology largely adopts relevant methodologies from forensic anthropology. Applying these osteolog-ical age-at-death, sex, and stature estimation methods to archaeological skeletal remains relies on the inherently flawed assumption that biological processes are homogenous across time and space. This paper offers a brief review of some of the key methods bioarchaeology has adopted from forensic anthropology, stressing the limitations of blindly using methods developed based on contemporary assemblages on archaeological ones, but also on systematic efforts that have been made to address these limitations.
... A natural progression of this work is to analyze the possible integration of a paragraph into the national catalographic normative concerning the study of vulnerability to crime incidents (e.g., theft and vandalism). This procedure can be included in the methodologies currently used in forensic sciences applied to natural and cultural heritage objects [105]. Moreover, future research might explore forwarding the catalographic records of endangered and sensitive specimens to law enforcement databases (e.g., [106]) to enhance the chances of recovering them in case of theft. ...
This paper aims to analyze the role of natural heritage cataloging when criminal events challenge natural history museums. This study investigates the rhino horn thefts in Italian natural history museums from 2011 to 2015 to provide a comprehensive framework for these robberies while highlighting the weaknesses and strengths to prevent thefts and safeguard both rhino horns and natural history collections from future targeting.
Osteoarchaeology: A Guide to the Macroscopic Study of Human Skeletal Remains covers the identification of bones and teeth, taphonomy, sex and ancestry assessment, age estimation, the analysis of biodistances, growth patterns and activity markers, and paleopathology. The book aims to familiarize the reader with the main applications of osteoarchaeology and provide the necessary knowledge required for the implementation of a broad range of osteological methods. It is ideal as a complement to existing textbooks used in upper level undergraduate and graduate courses on osteoarchaeology, human osteology, and, to some extent, forensic anthropology. Pedagogical features include ample illustrations, case study material, revision exercises, and a glossary. Additional features comprise macros that facilitate data processing and analysis, as well as an extensive chapter on applied statistics.
A free book on the amazing information we can extract from our ancestors' skeletons regarding their lives. What did they eat? How active were they? What diseases did they suffer from? And what does this biological information tell us about the ways in which they adapted to environmental and sociopolitical changes? Download Bare Bones and find out :)
We very much appreciate your input on how to improve this book, so please contact us with comments: e.nikita@cyi.ac.cy and m.mardini@cyi.ac.cy
Sex determination of the human pelvis has traditionally been done through visual analyses of morphoscopic traits and there are limited metric methods available to forensic anthropologists to add metric credibility to these analyses. The goal of this research was to create an improved metric method using three-dimensional geometric morphometrics to determine sex from both whole and modeled fragmented human pubic bones. The sample consisted of n = 378 pubic bones from the University of New Mexico’s Maxwell Museum Documented Skeletal Collection and eight landmarks were collected from each bone. Statistical analyses and machine learning algorithms were used to predict the accuracy of the method’s ability to classify a bone as male or female on both whole and simulated fragmented remains; this included tests run on each possible landmark combination of three or more landmarks to simulate fragmented bones (218 combinations). The results of the whole bone analysis resulted in 95.35% testing accuracy. The results of the modeled fragmentary analysis consisted of 164 combinations which exhibit a 90% or higher accuracy in sex prediction; and twelve combinations which exhibit 96% or higher accuracy in sex prediction. In particular, two landmarks clustered around the ventral arc of the pubic bone performed the best, indicating this is the most sexually dimorphic portion of the bone. These results indicate that three-dimensional geometric morphometrics is a valid method to be applied to sex determination in forensic anthropology.
Age-at-death is of paramount importance in forensic analysis of skeletal remains.
In addition to sex, stature, and population affinity, it constitutes baseline information in the identification process of deceased individuals. Despite its long tradition, in anthropological research
age-at-death estimation poses many challenges and unanswered questions. It is undisputedly among
the most difficult tasks of the forensic anthropologist and its results are often subject to a lackluster
performance. In this study, we assessed computationally the efficiency of a holistic approach to
skeletal age estimation based on a new proposal for macroscopic examination and the use of machine
learning-based models for data analysis. Our results suggest that this approach is key for accurate
and efficient age-at-death estimation based on skeletal remains analysis.
This article presents outcomes from a Workshop entitled “Bioarchaeology: Taking Stock and Moving Forward,” which was held at Arizona State University (ASU) on March 6–8, 2020. Funded by the National Science Foundation (NSF), the School of Human Evolution and Social Change (ASU), and the Center for Bioarchaeological Research (CBR, ASU), the Workshop's overall goal was to explore reasons why research proposals submitted by bioarchaeologists, both graduate students and established scholars, fared disproportionately poorly within recent NSF Anthropology Program competitions and to offer advice for increasing success. Therefore, this Workshop comprised 43 international scholars and four advanced graduate students with a history of successful grant acquisition, primarily from the United States. Ultimately, we focused on two related aims: (1) best practices for improving research designs and training and (2) evaluating topics of contemporary significance that reverberate through history and beyond as promising trajectories for bioarchaeological research. Among the former were contextual grounding, research question/hypothesis generation, statistical procedures appropriate for small samples and mixed qualitative/quantitative data, the salience of Bayesian methods, and training program content. Topical foci included ethics, social inequality, identity (including intersectionality), climate change, migration, violence, epidemic disease, adaptability/plasticity, the osteological paradox, and the developmental origins of health and disease. Given the profound changes required globally to address decolonization in the 21st century, this concern also entered many formal and informal discussions.
Age estimation is a key factor for identification procedure in forensic context. Based on anthropological findings, degenerative changes of the sternal extremity of the 4th rib are currently used for age estimation. These have been adapted to post-mortem computed tomography (PMCT). The aim of this study was to validate a post-mortem computed tomography method based on a revision of the Iscan’s method on a French sample. A total of 250 PMCT (aged from 18–98 years (IQR 36–68 years, median 51 years); 68 (27%) females) from the Medicolegal Institute of Paris (MLIP) were analyzed by two radiologists. The sternal extremity of 4th right rib was scored using method adapted from Iscan et al. Weighted κ was used to evaluate intra- and inter-observer reliability and Spearman correlation was performed to evaluate relationship between age and score. Confidence intervals for individual prediction of age based on 4th rib score and sex were computed with bootstrapping. The intra-observer reliability and inter-observer reliability were almost perfect (weighted κ = 0.85 [95%CI: 0.78–0.93] and 0.82 [95%CI 0.70–0.96] respectively). We confirmed a high correlation between the 4th rib score and subject age (rho = 0.72, p < 0.001), although the confidence intervals for individual age prediction were large, spanning over several decades. This study confirms the high reliability of Iscan method applied to PMCT for age estimation, although future multimodal age prediction techniques may help reducing the span of confidence intervals for individual age estimation.
Trial registration: INDS 0,509,211,020, October 2020, retrospectively registered.
Sex estimation is essential for forensic scientists to identify human skeletal remains. However, the most sexually dimorphic elements like pelvis or skull are not always assessable. Osteometric analyses have proven useful in sex estimation, but also to be population specific. The main purpose of this study was to test the validity of contemporary Greek and Spanish discriminant functions for the talus and the patella, respectively, on a Swiss skeletal sample and to quantify the utility of the measurements as a novel approach in osteometric sex assessment.
Four talus and three patella measurements on dry bone were obtained from 234 individuals of the modern cemetery SIMON Identified Skeletal Collection. The previously derived discriminant functions were applied, accuracies determined, the utility of the different measurements was assessed and new multivariable equations constructed.
Accuracies varied between 67% and 86% for talus and 63% and 84% for patella, similar to those reported by the original studies. Multivariable equations should be preferred over equations based on single measurements and combining the most significant measurements rather than using several variables obtained the best possible accuracy. The new discriminant functions did not provide a substantial improvement to the original ones. The overall utility of talus and patella is limited, allowing sex estimation with sufficient certainty only in a small proportion of individuals.
Discriminant functions developed in contemporary Greek or Spanish populations are in principle applicable also to Swiss contemporary populations. We recommend that at present existent studies of this type should be validated and tested rather than developing new formulas.
Since the professionalization of US‐based forensic anthropology in the 1970s, ancestry estimation has been included as a standard part of the biological profile, because practitioners have assumed it necessary to achieve identifications in medicolegal contexts. Simultaneously, forensic anthropologists have not fully considered the racist context of the criminal justice system in the United States related to the treatment of Black, Indigenous, and People of Color; nor have we considered that ancestry estimation might actually hinder identification efforts because of entrenched racial biases. Despite ongoing criticisms from mainstream biological anthropology that ancestry estimation perpetuates race science, forensic anthropologists have continued the practice. Recent years have seen the prolific development of retooled typological approaches with 21st century statistical prowess to include methods for estimating ancestry from cranial morphoscopic traits, despite no evidence that these traits reflect microevolutionary processes or are suitable genetic proxies for population structure; and such approaches have failed to critically evaluate the societal consequences for perpetuating the biological race concept. Around the country, these methods are enculturated in every aspect of the discipline ranging from university classrooms, to the board‐certification examination marking the culmination of training, to standard operating procedures adopted by forensic anthropology laboratories. Here, we use critical race theory to interrogate the approaches utilized to estimate ancestry to include a critique of the continued use of morphoscopic traits, and we assert that the practice of ancestry estimation contributes to white supremacy. Based on the lack of scientific support that these traits reflect evolutionary history, and the inability to disentangle skeletal‐based ancestry estimates from supporting the biological validity of race, we urge all forensic anthropologists to abolish the practice of ancestry estimation.
The estimation of the sex of the individual is a parameter of great value in forensic contexts and, above all, in archaeological contexts, where it is more difficult to apply genetic studies. In contrast with methods based on non-metric variables, we propose the use of a random generalized linear model for the determination of sex, starting from the Howells craniometric database and testing them on the dataset of known sex of the Forensic Data Bank, with 2524 and 1314 individuals respectively. After eliminating the individual’s considered outliers or with missing data, we proceeded to analyse which variables were more dimorphic between sexes (bizigomatic width, ZYB; bijugal width, JUB; mastoid height, MDH; glabela-occipital length, GOL; bifrontal width, FMB); these were used to build the statistical model. Subsequently, a comparison was made between the functions proposed by other authors and our model to determine their capacity in absolute terms, as well as by sex. The result is a random generalized linear model made up of 300 bags that, based on the five measures mentioned, reached 86.26% precision classifying the sex of individuals from the Forensic Data Bank (89.7% in the male sample and 82.82% in the female one). Although the method presented here should be taken with caution and not as the only way to estimate sex, it has proven to be statistically accurate in addition to having a non-regional vocation.
Objectives
Bioarcheological evidence suggests stature increased in males but decreased in females after the Black Death (1348‐1350 CE). Because tradeoffs between growth and reproduction can result in earlier ages at menarche and lower limb length, we assess menarcheal age between 1120 and 1540 CE to better understand the health of medieval adolescent females before and after the plague.
Materials and Methods
Our sample comprises 74 adolescent females from St. Mary Spital, London (1120‐1540 CE) within the age range during which menarche occurs (10‐25 years). They were assessed as being pre‐ or post‐menarcheal and divided into three groups: Early Pre‐Black Death (n = 13), Late Pre‐Black Death (n = 38), and Post‐Black Death (n = 23). Changes in the ages of pre‐ and post‐menarcheal females were assessed using Mann‐Whitney tests.
Results
The average age of post‐menarcheal females increased from the Early‐ to Late Pre‐Black Death periods and declined after the Black Death.
Conclusions
Short stature can reflect unfavorable growth environments, while younger menarcheal age indicates improved living conditions. The paradoxical pattern of female, but not male, stature reduction after the Black Death might reflect the association of early menarche with lower limb length and signal that adolescent females experienced improved health conditions after the epidemic. Our focus on pre‐ and post‐menarche within a limited age span provides a novel approach for inferring average ages of menarche over time. Pathways to skeletal development and reproductive investment are part of an integrated system, providing a bridge between life history research in bioarchaeology and human biology.
Age estimation is one of the main biological parameters to be determined for constructing an individual biological profile. In contexts where bones are poorly preserved, the use of teeth becomes relevant. Translucency of dentine has become relevant in recent decades, since the publication of the method proposed by Lamendin et al. (1992). In the local context, studies validating age-estimation methods from the permanent dentition are lacking. For this reason, it was decided to evaluate the performance of the age-estimation method proposed by Lamendin et al. (1992) in a sample of adult individuals with documented age belonging to the Lambre collection from the Municipal Cemetery of the city of La Plata. It was found that estimated age according to Lamendin et al.’s (1992) method varies by tooth type and age, being age the one that influences the estimates the most. On the other hand, sex has no influence in the estimation of age. The results showed no differences in the estimation in individuals between 35–50 years old, while exhibiting a tendency to overestimate age in young adults and to underestimate it in older ones.
Introduction
The purpose of this study was to analyze the respective contribution of the skull and mandible to sex estimation in an entire cranium using metric and geometric morphometric methods and multislice computed tomography (MSCT) analysis.
Materials
The study sample comprised 120 individuals aged 23 to 84 years and divided into three groups (whole sample and over or under 40 years of age).
Methods
Forty-eight osteometric landmarks were positioned using Osirix®, 34 for the cranium and 14 for the mandible. The data were analyzed using univariate analyses and logistic regression using backward stepwise selection with cross-validation of the classification results. Generalized procrustes analysis (GPA) was used, and Goodall’s F test and Mahalanobis D² matrices allowed an assessment of statistical significance.
Results
The classification accuracy of cranium models ranged from 87% to 88.3%, and from 68% to 81.4% for the mandibular models. With geometric morphometry, accuracy was of 94–100% for the cranium and 84.2% for the mandible.
Discussion
We conclude that the mandible had a higher accuracy rate for individuals over 40 years than individuals under 40 years of age, although the accuracy of geometric morphometry did not differ significantly between the age groups. The cranium, however, presented greater predictability for all the parameters assessed.
Pelvic morphology is highly reflective of both sex and age changes in humans, making it a popular research focus in forensic anthropology. Relevant studies range from traditional descriptive to more complicated approaches involving statistical modeling, with the latter having become excessively popular in the last decades. The present study examines the performance of Bayesian statistics in age estimation based on the morphological changes observed on the iliac auricular surface. The aim is two-fold: a) to test whether a Bayesian approach can improve age-at-death estimation compared to the original Lovejoy et al. (1985a) and Buckberry and Chamberlain (2002) methods, and b) to explore the impact of adopting different samples as informative priors as well as for obtaining the transition analysis parameters. For this purpose, two modern Greek documented collections have been used, the Athens and the Cretan Collection. Our results found no clear improvement in age prediction when adopting Bayesian age estimation, with only one exception: Athenian males for the Buckberry and Chamberlain (2002) method. The choice of samples for transition analysis and as informative priors affected the results but this effect was statistically non-significant.
Objectives:
This paper proposes a method for the quantification of the shape of sexually dimorphic cranial traits, namely the glabella, mastoid process and external occipital protuberance.
Materials and methods:
The proposed method was developed using 165 crania from the documented Athens Collection and tested on 20 Cretan crania. It is based on digital photographs of the lateral view of the cranium, drawing of the profile of three sexually dimorphic structures and calculation of variables that express the shape of these structures.
Results:
The combinations of variables that provide optimum discrimination between sexes are identified by means of binary logistic regression and discriminant analysis. The best cross-validated results are obtained when variables from all three structures are combined and range from 75.8 to 85.1% and 81.1 to 94.6% for males and females, respectively. The success rate is 86.3-94.1% for males and 83.9-93.5% for females when half of the sample is used for training and the rest for prediction. Correct classification for the Cretan material based upon the standards developed for the Athens sample was 80-90% for the optimum combinations of discriminant variables.
Discussion:
The proposed method provides an effective way to capture quantitatively the shape of sexually dimorphic cranial structures; it gives more accurate results relative to other existing methods and it does not require specialized equipment. Equations for sex estimation based on combinations of variables are provided, along with instructions on how to use the method and Excel macros for calculation of discriminant variables with automated implementation of the optimum equations.
The current paper examines the accuracy of existing binary logistic regression equations for sex prediction based on pelvic and cranial traits in a modern Greek assemblage and proposes new equations with the aim of improving correct classification rates for Balkan material. Our results suggest that existing equations based on pelvic traits perform very well on the Greek material, which can be attributed to the fact that sexual dimorphism in the pelvis results from common evolutionary forces across populations. In contrast, equations based on cranial traits are highly dependent upon the populations based on which they were developed, stressing the need to produce more population-specific functions. Our proposed equations achieve correct sex classification in 92.59% of the females and 95.79% of the males for pelvic traits, while these percentages rise to 97.53% for females and 98.95% for males when the vertical femoral head diameter is included in the models. Our functions based on cranial traits produced correct classifications in up to 92.59% of females and 88.42% of males, and when the cranial scores where combined with the vertical femoral head diameter, the correct classification rates increased to 93.83% for females and 94.73% for males. Prior to the generalization of the use of these functions, further research examining their accuracy in other groups is required, but our results appear promising.
Sexual dimorphism in the human pelvis has evolved in response to several jointly acting selection regimes that result from the pelvis? multiple roles in locomotion and childbirth, among others. Because human males are, on average, taller than females, some aspects of sexual dimorphism in pelvis shape might result from allometry, the association between stature and pelvis shape across individuals. In this study, they aimed to disentangle and quantify the two components contributing to pelvic sex differences: the allometric component, which emerges as a consequence of dimorphism in stature, and the remaining non-allometric sexual dimorphism component. A geometric morphometric analysis of a dense set of 3D landmarks, measured on 99 female and male adult individuals was conducted. While pelvis size was similar in both sexes, the average differences in pelvis shape reflected the well-documented pattern of sexual dimorphism. There was almost no overlap between females and males in shape space. Their analysis showed that pelvis size and shape were similarly associated with stature in both sexes. It was found that dimorphism in the height-to-width ratio of the pelvis and in the orientation of the iliac blades was largely allometric, whereas dimorphism in the subpubic angle and the relative size and distance of the acetabula was largely non-allometric. It was concluded that, in contrast to the overall pelvic proportions, sexual dimorphism in the birth-relevant pelvic dimensions was mainly of non-allometric origin and was presumably mediated via steroid hormone secretion during puberty. Anat Rec, 300:698?705, 2017.
In forensic anthropology, age-at-death estimation typically requires the macroscopic assessment of the skeletal indicator and its association with a phase or score. High subjectivity and error are the recognized disadvantages of this approach, creating a need for alternative tools that enable the objective and mathematically robust assessment of true chronological age. We describe, here, three fully computational, quantitative shape analysis methods and a combinatory approach that make use of three-dimensional laser scans of the pubic symphysis. We report a novel age-related shape measure, focusing on the changes observed in the ventral margin curvature, and refine two former methods, whose measures capture the flatness of the symphyseal surface. We show how we can decrease age-estimation error and improve prior results by combining these outline and surface measures in two multivariate regression models. The presented models produce objective age-estimates that are comparable to current practices with root-mean-square-errors between 13.7 and 16.5 years.
This study addresses issues associated with limited access to reference skeletal collections and how it hampers regional methodological development. The study also investigates the effects of three different priors on age-at-death estimations of Koreans and quantifies the accuracy of Bayesian estimation compared to a non-Bayesian approach.
CT scan images of pubic symphyses were scored following the Suchey-Brooks standards. We specifically examine Bayesian age-at-death estimations under an optimal scenario where both the likelihood and prior probability are derived from a target population of Korean origin. Three different priors (population, forensic, and uniform priors) are evaluated for their age estimation accuracy levels.
The results showed that Korean males and females had discrepancies in skeletal aging rates only in certain phases. A similar trend was observed in the comparison of the original Suchey-Brooks and Korean sample aging rates. However, when final age estimates were computed based on an inadequate choice of a prior, the between-group differences may be minimized or even obscured. The uniform and forensic priors produced the most reasonable and unbiased estimates, while the uniform prior consistently provided open-ended estimates for the last phase. The population prior produced consistently higher estimates due to the high survivorship of Koreans. In addition, the original Suchey-Brooks standards persistently under-estimated ages for Korean males and females.
Overall, when Bayesian age estimation is based on an informed prior that best matches the context of the case (forensic deaths in this study), there was increased accuracy of final age estimates compared to age estimates of other priors and the original Suchey-Brooks method.
Skeletal sex estimation is an essential step in any osteoarchaeological study; hence, several metric and morphological methods have been developed for this purpose, employing different skeletal elements. This paper has a dual purpose: 1. Test the performance of several machine learning classification models for skeletal sex estimation using worldwide samples of cranial and postcranial measurements, and 2. Present a free web application for the implementation of the models that exhibit the highest accuracy so that the sex of unknown skeletons can be straightforwardly estimated. Regarding the first objective, using the Goldman database of postcranial metrics and the William W. Howells craniometric database, machine learning classification models were constructed for sex prediction. The models were optimized with respect to their hyperparameters and cross‐validated reaching accuracies ranging from 80.8‐89.5% for the postcranial data and 81.2‐87.7% for the cranial data. The models offering the highest rates of correct sex classification (Extreme Gradient Boosting, Light Gradient Boosting and Linear Discriminant Analysis) were then selected to construct an open access and open source web application, SexEst, for predicting the sex of unknown skeletons.
Suchey-Brooks method has been studied many times with varying reports of accuracy and reliability. A systematic review and meta-analyses were utilized to quantitatively determine the accuracy and reliability of the Suchey-Brooks (S-B) method. A systematic search of PubMed and EBSCO health and medical databases was performed. Meta-analyses were performed to quantify the relationship between actual known age at death and the S-B method using Spearman's Rho and Pearson's r for (1) combined males and females estimates, (2) male-only estimates, and (3) female-only estimates. Overall correlation coefficient using Cohen's kappa, Spearman's Rho, and Pearson's r was also calculated to determine the interrater and intrarater reliability using the S-B method. Eighteen studies classified as moderate-to-high methodological quality met the inclusion criteria. The sample sizes were different for the combined male and female (n = 2620), male-only (n = 2602), and female-only (n = 1431) meta-analyses. The effect size of the age at death meta-analyses was large and significant for combined males and females (Spearman's Rho = 0.62; Pearson's r = 0.65), male-only (Spearman's Rho = 0.77; Pearson's r = 0.75), and female-only (Spearman's Rho = 0.71; Pearson's r = 0.71). The overall correlation coefficients of the interrater (Kappa = 0.76; Spearman's Rho = 0.73; Pearson's r = 0.80) and intrarater (Kappa = 0.81; Spearman's Rho = 0.91; Pearson's r = 0.83) reliability meta-analyses were large and significant. A significant degree of heterogeneity was present in all meta-analyses, with minimal evidence of publication bias. The meta-analyses results suggest the S-B method is highly reliable with a moderate-to-high degree of accuracy. Our results also identified sample size and accuracy differences between male and female individuals.
Identified (documented) osteological collections represent an important resource in the development of forensic anthropology standards and methods as well as a precious tool for learning and training of practitioners. Even though the number of papers presenting identified collections worldwide increases, many of the collections have still not been divulged to the scientific community in sufficient detail to ascertain their exact number. The Forensic Anthropology Society of Europe (FASE) therefore developed a tool that goes beyond sporadic publications: the FASE Map of Identified Osteological Collections, which is freely accessible and continuously updated and revised. The online map is available at http://forensicanthropology.eu/osteological-collections/. The map of skeletal collections was created in 2017 and currently displays information on 153 identified osteological collections (43 of them categorized as contemporary) located in 41 different countries. This article offers a short analysis of the type, geographical location and content of the collections included in the map. The aim of this article and the map as such is to provide a useful resource to facilitate research planning and teaching in forensic anthropology and related disciplines.
Age estimation is one of the crucial first steps in the identification of human skeletal remains in both forensic and archaeological contexts. In the postnatal period, age is traditionally estimated from dental development or skeletal growth, typically long bone diaphyseal length. However, in many occasions other methods are required. This study provides alternative means of estimating age of juvenile remains from the size of several cranial bones and the mandible. A sample of 185 identified juvenile skeletons between birth and 13 years of age from two European collections were used (Lisbon and Spitalfields). Measurements of the frontal, occipital-lateralis, occipital-basilaris, occipital-squamous, zygomatic, maxilla, and mandible were used to calculate classical calibration regression formulae for the sexes combined. The sample was divided into three age groups birth to 2 years, 2 to 6 years, and 2 to 12.9 years, depending on bone and its growth trajectory. For all the bones, measurements of the youngest age groups yielded the most precise age estimates. The vault bones on average yielded the best performing models, with the frontal bone having the most precise of all. The mandible performed on par with the best performing cranial bones, particularly in individuals under the age of 2 years. This study provides one of the most comprehensive approaches to juvenile age estimation based on bones of the skull, providing a resource that potentially can help estimate age of juvenile skeletons from a variety of circumstances.
Objectives:
Reconstructing demography of past populations using skeletal data is challenging when analyzing adults because the process of biological aging does not always reflect the individual's chronological age. A proposed solution to address the limitations of traditional age estimation methods is transition analysis (TA), a multifactorial method of age estimation. However, despite its methodological refinement, TA has varying degrees of accuracy when applied to different known-age skeletal samples. This study assesses TA's accuracy by comparing age estimates to known age at death in the Hamann-Todd Collection.
Materials and methods:
We contrasted the maximum likelihood age estimates generated by the ADBOU program to the known ages of 221 individuals. The absolute error was calculated for the entire sample, and compared between sex and ancestry.
Results:
The mean absolute error in the sample is 11.6 (SD = 10.3) years, with white individuals' errors (14.1 years) being significantly higher than black individuals' (9.1 years; p < 0.001). No significant differences were found between sexes (p = 0.621). A weak to moderate positive correlation was found between known age and absolute error for white males (R = 0.607; p < 0.001), white females (R = 0.509; p < 0.001), and black males (R = 0.371; p = 0.006). The accuracy of TA age estimates varied when each anatomical region was analyzed independently, but the combination of all three anatomical regions yielded the most accurate age estimates.
Discussion:
These findings further support that TA accuracy depends on the prior distribution used and, in the Hamann-Todd Collection, the accuracy for white individuals is more influenced by this limitation than when black individuals are analyzed.
Sex estimation is a crucial component of the biological profile. Stull et al. (2017) have proposed a promising juvenile sex estimation method using long bone measurements taken from a South African sample, providing relatively high classification accuracies and made easy to use via the KidStats web-based app. In this study, we test the models developed by Stull et al. (2017) on an external historic population from Lisbon, Portugal, in order to determine whether the models can be reliably applied to archeological and forensic populations outside of the original population sample. The study sample consisted of 102 individuals (45 females and 57 males) aged under 13 years at death from the Lisbon identified skeletal collection. Measurements from these individuals were used to test the flexible discriminant analysis (FDA) models given by Stull et al. (2017). Allocation accuracies were calculated for boys and girls and children over and under 2 years separately and combined. Our findings show that the models developed by Stull et al. (2017) yield poor accuracy when applied to our external population and thus can potentially be misapplied on archeological skeletal remains or forensic remains of unknown origin. A number of statistical issues may explain why models fail to be transportable or even generalizable, namely multicollinearity, model overfitting and overly optimist bootstrapped cross-validation rates. It is also likely that population differences in size and sexual size dimorphism also affected the applicability of the models. We emphasize the importance of externally validating prediction models, particularly if they are intended to be applied across populations. Our study addresses Stull and co-worker's request for further validation of the method on populations outside of South Africa, as the models cannot be confidently applied in the field until it has been externally validated.
Fragmented human remains present a challenge for forensic experts as they attempt to identify individuals using standard forensic methods. Several histological age estimation techniques have been developed during the last fifty years to aid in this process. However, very few validation studies have been conducted in order to test their accuracy and bias, and thus, validation assessment is required as we employ them while testifying in court.
Histological variables are assessed from rib thin-sections from two Mediterranean samples; Cretan (N=41) and Cyprus (N=47). Intra and inter-observer errors are assessed through TEM analysis and Intra-class Correlation Coefficient by testing observers with different levels of experience as they collected data on osteon counts and area measurements. The relation between the variables and age is determined using correlation coefficients. Histomorphometric data are applied to four widely used age estimation formulas assessing the performance of the methods for the entire sample. Inaccuracy and bias are calculated with age estimations and known age tested for significance and proportional bias assessed.
Overall, histological parameters presented acceptable intra- and inter-observer errors. All variables exhibited statistically significant correlation with age (P < 0.01). For three of the techniques, data showed a systematic underestimation of age with an increase in inaccuracy in older individuals. One of the age estimation formulas produced overestimation of young individuals yet, it more accurately estimated the age of older individuals.
This validation study explores inter-population variation in bone remodeling dynamics and presents a critical evaluation on methodological issues that can affect the performance of existing histological techniques.
This study assesses whether greater levels of physical activity result in increased rates of degenerative change in the pubic symphysis and the iliac auricular surface. The sample comprises 131 skeletons from the Athens Collection. Skeletal age‐at‐death was estimated from the pubic symphysis and the iliac auricular surface. Skeletal activity was assessed using femoral cross‐sectional geometric (CSG) properties and fibrocartilaginous entheses. The association between skeletal age stages, CSG properties and entheseal changes (EC) was tested using Spearman correlation followed with partial Spearman correlation controlling for the effect of documented age‐at‐death and estimated body mass, as well as generalised linear models. Moreover, Kruskal–Wallis tests were used to compare the EC and CSG values among individuals who were underaged, correctly aged and overaged using the pubic symphysis and the iliac auricular surface. Our results show a negative correlation of skeletal age stages with particular CSG properties, implying a decrease in skeletal rigidity as age increases, and a positive correlation with EC scores, suggesting that older individuals exhibit more pronounced EC. Controlling for documented age‐at‐death and body mass produced low correlation coefficients and very few statistically significant results. The difference in EC and CSG values among underaged, correctly aged and overaged individuals was significant only for ECs in individuals over 50 years old. The present study highlights that the effect of activity on pelvic age markers is not pronounced, because a limited association between activity and skeletal degeneration in the pubic symphysis and iliac auricular surface was found. Considering the difficulty in identifying past occupations skeletally, our study supports that this often missing parameter in past osteobiographies does not affect skeletal age estimation. Moreover, our results suggest that taking into account the EC scores when evaluating skeletal age can provide further insights in age‐at‐death estimation in older individuals.
Biodistance studies have a long presence in Eastern Mediterranean and Middle Eastern (EMME) bioarchaeology. In line with trends seen in North America and elsewhere, such studies were originally typological and were often adopted to explore mass migrations, while after the advent of New Archaeology in the 1960 s, the research questions started covering issues of past population structure and short-distance mobility, and the statistical methods adopted became increasingly sophisticated. Nowadays, despite the revolution in ancient DNA and isotope studies, biodistance analyses are still broadly applied in EMME assemblages to address an ever-expanding range of topics. This paper provides a brief overview of biodistance studies in this region, with a focus on their temporal evolution. In addition, it discusses the directions in which such studies should move in the near future, with an emphasis on the need for even more studies, association of the results with other bioarchaeological, material cultural, historical and ecological information, and methodological standardization.
Palatal suture fusion has seen little testing and/or application due in part to an inadequately described relationship to formal age ranges. This study presents a modified scoring method that examines fusion on samples of modern documented adult males and compares two Bayesian approaches to age estimation. In the first analysis, American and Portuguese collections were used to derive univariate and multivariate transition analysis (TA) parameters, which combined with an informative prior, estimated age in a sample of modern Americans and Portuguese. For the second analysis, a Bayesian multiple linear regression (BMLR) used indicator statuses as the independent variables with age as the dependent variable. Highest posterior density regions (HPDRs) and highest posterior density intervals (HDI) were calculated for a holdout sample. Final age estimates for the methods were tested for accuracy using cumulative binomial tests at 75% and 90% coverages. The HPDRs from multivariate TA captured age better for younger individuals, but consistently underaged. The cumulative binomial tests on the BMLR results indicated the prediction intervals performed as expected, and we show they are narrower (more precise) and/or more accurate than the corresponding HPDR. The modified method presented here formally links palatal suture obliteration to age using two different approaches, one of which (BMLR) is new to the aging literature. The BMLR provided results free from bias and more reasonable age ranges while maintaining accuracy. We present a look‐up table and a free, simple R file for users to download and run their own estimates with BMLR.
Subadult sex estimation is routinely advised against, as most researchers believe there are not sufficient differences between the subadult male and female skeletons. This chapter discusses the intricacies of sexual differentiation and the expression of sexual dimorphism, the obstacles that plague the progress of subadult sex estimation research, and introduce the research that has been conducted to estimate sex from numerous skeletal elements. Subsequently, the biological and methodological mechanisms that may impede attainment of high classification accuracies are discussed. The chapter is transparent about the difficulties associated with subadult sex estimation and the consistent trend for unsuccessful validation studies. Even so, there is promise for subadult sex estimation with the incorporation of innovative techniques and virtual skeletal collections from diverse populations to address the lack of subadult material, especially where variability is concerned. Ultimately, we hope to encourage researchers to persevere, as the absence of evidence is not the same as the evidence of absence.
Histological methods can be used forensically to estimate age-at-death based on patterns of change in osteon shape, size, and population density, all of which result from the continuous process of bone remodelling. The present study examines the applicability of three existing histological age-at-death estimation methods as applied to an Australian population of known age and sex. Microradiographs from 50 mid-shaft femora thin sections, equally divided by sex, were obtained from the Melbourne Femur Reference Collection (MFRC); stated chronological age-at-death is 18 to 88 years. Osteon shape metrics are measured using ImageJ and the age-at-death prediction formulae of i) Singh and Gunberg, ii) Keough et al., and iii) Goliath et al. are applied. The relationship between estimated and actual age-at-death is then statistically quantified. All three formulae demonstrate pooled and sex-specific SEE values in excess of 20 years: i) pooled ±22.92 (♂±20.91, ♀±25.20); ii) ±20.79 (♂±20.96, ♀±21.05); and iii) ±35.43 (♂±32.68, ♀±38.66). When individuals under 40 years of age were excluded from the analysis, only two of the methods demonstrated increased accuracy: i) pooled ±20.87 (♂ ±17.47, ♀ ±23.70); ii) pooled ±18.21 (♂±16.51, ♀±19.90); and iii) pooled ±41.18 (♂ ±40.12, ♀ 43.05). The present study represents a preliminary investigation of the accuracy of existing histological age-at-death standards applied in an Australian population of known age.
Objective:
This study describes secular trends in physical stature, Cormic Index (CI), and body mass index (BMI) of adult Makushi Amerindians born between 1910 and 1980, compares the stature of these Makushi adults to Makushi adults measured in 1921, and provides contextual data to inform the findings.
Methods:
Pearson's correlation was used to assess the relationship between year of birth and physical stature, BMI, and CI for 231 females and 113 males, 20 to 90 years of age measured in 2000 to 2001. Wilcoxon's test was used to compare physical stature of Makushi adults measured in 2000 to 2001 with that of 40 Makushi adults measured in 1921.
Results:
Among Makushi measured in 2000 to 2001, females and males born more recently were taller and had a lower CI but did not differ in BMI relative to their elders. Makushi measured in 2000 to 2001 are significantly taller than those Maksuhi measured in 1921.
Conclusion:
The increased physical stature of and decreased CI in more recently born Makushi may be explained by a more favorable early life environment possibly due to public health measures and dietary changes. As well, trends in stature may be linked to genetic admixture with African-Guyanese migrating into the region during this time.
Historically, morphometric standards used in forensic anthropology and bioarchaeology were derived from individuals
of African and European descent, along with ancient Native Americans. However, it is unlikely that these standards can be accurately
applied to modern Asian populations, and they may introduce error into biological profiles. Due to different population histories, it is hypothesized
that ancient Native American and modern Thai individuals are morphometrically distinct. This study investigates the differences in
sexual dimorphism between 102 Native American adults and 100 Thai individuals, 17 to 96 years old. A total of 30 cranial, 8 mandibular,
and 58 postcranial measurements were compared between the two groups. Using independent t-tests,
MANOVAs, univariate sectioning
points, and linear discriminant functions, the Native American and Thai samples were found to be significantly different in the expression
of sexual dimorphism for many elements. Further, measurements tested in Spradley and Jantz’s (2011) American Black and American White
discriminant function equations produce correct classification biases of –91.0–
100.0%
and often fail to correctly classify Native American
and Thai individuals. Therefore, the metric sex estimation methods developed on non-Asian
populations do not adequately classify Native
American and Thai individuals, thereby underscoring the importance of population-specific
equations. The population-specific
statistics
developed for the Native Americans correctly classify 48.1–93.8%
(univariate) and 70.8–94.1%
(multivariate) of individuals, while those
developed for the Thai correctly classify 47.8–93.0%
(univariate) and 63.2–100.0%
(multivariate). The most discriminating elements are
population dependent: the humerus, clavicle, and tibia work best for Native Americans, while the os coxa, ulna, and scapula perform best
for Thai individuals.
The aim is to study the sexual dimorphism of the base of the skull in radiographs of a bone collection of contemporary Colombian adults, with the intention of formulating discriminant functions capable of classifying sex in this population. The sample consisted of 115 skull base radiographs, (44 females and 71 males), which originated from the Colombian Human Skeletals Collection. Radiographs with good contrast were selected. Images of skulls with asymmetries and fractures were excluded. Five measures: Maximum cranial base length, Foramen magnum length, Maximum cranial breadth, Bizygomatic breadth, Foramen magnum breadth length, were preformed using ImageJ5 software ®; an intra-observer error was determined using paired t-test. Statistical analysis showed a sexual dimorphism for all variables (p < 0.05). The step-by-step procedure of the discriminant function selected 2 variables from the 5 (Foramen magnum length and Bizygomatic breadth) and the precision was between 86.4% and 88.6% in the determination of sex. However cross-validation showed an accuracy of 85.7% to male and 87.2% to female. The skull base is highly dimorphic. The established discriminant functions can be used to estimate sex in the Colombian population.
Objective
CT scans have become a standard part of autopsy procedures in large medical-legal facilities, and forensic anthropologists are increasingly asked to contribute their knowledge of skeletal anatomy to volume-rendered images (VRIs) generated from CT scans. However, it is not clear if the age estimation methods created using skeletal remains can be reliably applied to VRIs. This study, along with the other two in this series, examines the applicability of three commonly used sites for adult skeletal age estimation on VRIs generated from CT scans of cadavers. Part I focuses on the fourth rib.
Materials and methods
CT scans of 420 cadavers from the Victorian Institute of Forensic Medicine were selected (age range 20–79 years). Siemens syngo.via software was used to view the DICOM images and create the VRIs. The İşcan et al. and Hartnett fourth rib methods of age estimation were used to create a revised method for VRIs.
Results and conclusion
Several features described by both İşcan et al. and Hartnett could be observed on the VRIs; however, features such as porosity inside the sternal rib and bone weight could not be assessed. A revised fourth rib method for use on VRIs was created. Significantly more individuals were placed in the correct age phase using the revised method compared to the İşcan et al. and Hartnett methods, and overall the revised method had significantly improved inaccuracy and bias scores. The revised method is reliable and should be tested on other populations using different software.
The present study tests the accuracy of commonly adopted ageing methods based on the morphology of the pubic symphysis, auricular surface and cranial sutures. These methods are examined both in their traditional form as well as in the context of transition analysis using the ADBOU software in a modern Greek documented collection consisting of 140 individuals who lived mainly in the second half of the twentieth century and come from cemeteries in the area of Athens. The auricular surface overall produced the most accurate age estimates in our material, with different methods based on this anatomical area showing varying degrees of success for different age groups. The pubic symphysis produced accurate results primarily for young adults and the same applied to cranial sutures but the latter appeared completely inappropriate for older individuals. The use of transition analysis through the ADBOU software provided less accurate results than the corresponding traditional ageing methods in our sample. Our results are in agreement with those obtained from validation studies based on material from across the world, but certain differences identified with other studies on Greek material highlight the importance of taking into account intra- and inter-population variability in age estimation.
The fourth rib has been used commonly in order to estimate age at death and even sex in skeletal remains but many often, Iscan's estimates do not adjust to the real age of the individual. Population specific references for sex and age-at-death estimation from the sternal end of the fourth rib are presented for a contemporary Mexican sample. A total of 504 ribs with known sex and age from a morgue sample were studied (444 males, 60 females, 17 to 92 years old). The height and breadth of the sternal end of the rib were sexually dimorphic (p = .000), and allowed a correct sex assignment in 73.3% to 84% of the cases from univariate and multivariate discriminant functions. With regard to age-at-death estimation, the morphological changes summarized by the phases of the sternal end of the fourth rib are correlated with known age in this sample (Spearman's Rho, p = .000). However, the original age intervals tend to underestimate age at death and inaccuracy increases with phase scored in males. Descriptive statistics for rib phase are provided for males and females, and new age-at-death estimates based on transition analysis and Bayesian statistics are provided for the male sample. The test of universally applied methods and the development of population specific references is an important task for forensic anthropology around the world.
Cranial suture closure, one of the most commonly used age estimation methods, for decades, however, is often viewed with caution and its reliability is still debated. Few methods of estimating age using the skeleton, especially cranial suture, have been tested on Thais. This study aims to test the traditional aging techniques using cranial suture closure on Thai individuals in order to identify the error rate of each method when applied to a Thai sample. Meindl and Lovejoy (1985), Acsádi and Nemeskéri (1970), and Mann (1991) methods were applied to 175 Thai dry crania. Bias and inaccuracy in the Meindl and Lovejoy, Acsádi and Nemeskéri, and Mann methods resulted in overestimation in young adults and underestimation in older individuals with an inaccuracy range of approximately 13-22 years. The Mann method approached 100% in predicting age in older males, but the method did not fare as well on Thai females. The results confirm inter-population variation does exist. Additionally, differences in age composition between populations used to develop the methods and Thais may lead to an increase in error. This study indicates that these three aging methods should be used in conjunction with other techniques. Further research which develops specific methods for Thais might give better results for age estimation.
Body size is an important variable in bioarchaeological and forensic studies, making the accurate calculation of stature and body mass imperative. Given that anatomical and morphometric approaches offer accurate results but require a particularly good preservation of the skeletal material, whereas mathematical and mechanical methods are more easily applicable but they are largely population-specific, the present paper uses a 'hybrid' approach in order to generate regression equations for the prediction of stature and body mass in a modern Greek sample. Specifically, anatomical and morphometric methods were used to calculate the stature and body mass of the individuals and regression equations using the Ordinary Least Squares and Reduced Major Axis methods were generated with long bone lengths and femoral head breadth as predictors. The obtained equations exhibit low random and directional error and perform better than existing equations designed using different samples from the United States, Europe, and the Balkans. Therefore, these equations are more appropriate for modern Greek material.
Objectives:
Though applied in bioarchaeology, dental wear is an underexplored age indicator in the biological anthropology of contemporary populations, although research has been conducted on dental attrition in forensic contexts (Kim et al., , Journal of Forensic Sciences, 45, 303; Prince et al., , Journal of Forensic Sciences, 53, 588; Yun et al., , Journal of Forensic Sciences, 52, 678). The purpose of this study is to apply and adapt existing techniques for age estimation based on dental wear to a modern American population, with the aim of producing accurate age range estimates for individuals from an industrialized context.
Materials and methods:
Methodologies following Yun and Prince were applied to a random sample from the University of New Mexico (n = 583) and Universidade de Coimbra (n = 50) cast and skeletal collections. Analysis of variance (ANOVA) and linear regression analyses were conducted to examine the relationship between tooth wear scores and age.
Results:
Application of both Yun et al. () and Prince et al. () methodologies resulted in inaccurate age estimates. Recalibrated sectioning points correctly classified individuals as over or under 50 years for 88% of the sample. Linear regression demonstrated 60% of age estimates fell within ±10 years of the actual age, and accuracy improved for individuals under 45 years, with 74% of predictions within ±10 years.
Discussion:
This study demonstrates age estimation from dental wear is possible for modern populations, with comparable age intervals to other established methods. It provides a quantifiable method of seriation into "older" and "younger" adult categories, and provides more reliable age interval estimates than cranial sutures in instances where only the skull is available.
During the 20th century a general positive secular trend for stature is observed in developed countries around the world while shorter statures, often associated with a lack of a positive secular trend, have mostly been observed in populations with lower SES. The purpose of this study was to compare secular changes in stature between 20th century South Africans of European descent and two European populations. The comparative samples include Dutch males with which there is an assumed genetic relationship, and Swiss males for which the genetic association is less clear. The sample comprised anthropometric stature data of white South Africans (17 - 62 years), Swiss and Dutch males (18 - 21 years) obtained from military conscripts with birth cohorts of 5 years from 1946 to 1995. The stature of white South African males did not increase at a significant rate compared to those observed in Swiss and Dutch males. South African and Dutch males were of similar height following World War II, but a considerable trend was observed only in the Dutch group. The Swiss group was initially shorter than the South Africans, but due to a positive secular trend their average stature is on a par with that of South Africans in the most recent cohort. The lack of a significant positive secular trend in the South African group could suggest that factors such as gene flow and poor economic and social development in South Africa resulted in shorter statures in white South African groups than expected.
Objectives:
A new tool for skeletal sex estimation based on measurements of the human os coxae is presented using skeletons from a metapopulation of identified adult individuals from twelve independent population samples. For reliable sex estimation, a posterior probability greater than 0.95 was considered to be the classification threshold: below this value, estimates are considered indeterminate. By providing free software, we aim to develop an even more disseminated method for sex estimation.
Materials and methods:
Ten metric variables collected from 2,040 ossa coxa of adult subjects of known sex were recorded between 1986 and 2002 (reference sample). To test both the validity and reliability, a target sample consisting of two series of adult ossa coxa of known sex (n = 623) was used. The DSP2 software (Diagnose Sexuelle Probabiliste v2) is based on Linear Discriminant Analysis, and the posterior probabilities are calculated using an R script.
Results:
For the reference sample, any combination of four dimensions provides a correct sex estimate in at least 99% of cases. The percentage of individuals for whom sex can be estimated depends on the number of dimensions; for all ten variables it is higher than 90%. Those results are confirmed in the target sample.
Discussion:
Our posterior probability threshold of 0.95 for sex estimate corresponds to the traditional sectioning point used in osteological studies. DSP2 software is replacing the former version that should not be used anymore. DSP2 is a robust and reliable technique for sexing adult os coxae, and is also user friendly.
Objectives:
This study provides classical calibration regression formulae for age estimation from the dimensions of unfused shoulder and pelvic girdle bones.
Materials and methods:
Age estimation models were derived from a sample of 160 known age and sex individuals (63 females and 97 males) aged birth to 12 years, selected from Portuguese and English skeletal collections. The sample was divided into two age groups at the age of 2 years, and formulae were obtained for the sexes separately and combined.
Results:
Measurements of the pelvis provide more precise age estimates than the shoulder. In the younger age group, the height and width of the ilium, and the height of the glenoid yield the most precise age estimates. In the older age group, the length of the clavicle provides the most precise estimates, followed by measurements of the pubis and ischium.
Discussion:
In the younger individuals (<2 years), age estimates based on measurements of the pelvic girdle seem to be as or more precise than those based on the length of long bones. In older individuals (≥2 years), estimates based on the measurements of the girdles are less precise than those based on the length of long bones. These age estimation formulae may be useful for fragmentary and incomplete material in archaeological and forensic contexts. The formulae are suitable for a variety of archeological populations living under adverse conditions. These conditions are similar to some "developing" countries, and hence the formulae may also be applicable to modern forensic remains from such environments.
Sex estimation is an integral aspect of biological anthropology. Correctly estimating sex is the first step to many subsequent analyses, such as estimating living stature or age-at-death. Klales et al. (2012) provided a revised version of the Phenice (1969) method that expanded the original three traits (ventral arc, subpubic concavity/contour, and medial aspect of the ischio-pubic ramus) into five character states to capture varying degrees of expression within each trait. The Klales et al. (2012) method also provided associated probabilities with each sex classification, which is of particular importance in forensic anthropology. However, the external validity of this method must be tested prior to applying the method to different populations from which the method was developed. A total of 1,915 innominates from four diverse geographic populations: 1) U.S. Blacks and Whites; 2) South African Blacks and Whites; 3) Thai; and 4) unidentified Hispanic border crossers were scored in accordance with Klales et al. (2012). Trait scores for each innominate were entered into the equation provided by Klales et al. (2012) for external validation. Additionally, recalibration equations were calculated with logistic regression for each population and for a pooled global sample. Validation accuracies ranged from 87.5–95.6% and recalibration equation accuracies ranged from 89.6% − 98% total correct. Pooling all samples and using Klales’ et al. (2012) equations achieved an overall validation accuracy of 93.5%. The global recalibration model achieved 95.9% classification accuracy and can be employed in diverse worldwide populations for accurate sex estimation without the need for population specific equations.
Developmental Juvenile Osteology was created as a core reference text to document the development of the entire human skeleton from early embryonic life to adulthood. In the period since its first publication there has been a resurgence of interest in the developing skeleton, and the second edition of Developmental Juvenile Osteology incorporates much of the key literature that has been published in the intervening time. The main core of the text persists by describing each individual component of the human skeleton from its embryological origin through to its final adult form. This systematic approach has been shown to assist the processes of both identification and age estimation and acts as a core source for the basic understanding of normal human skeletal development. In addition to this core, new sections have been added where there have been significant advances in the field. Identifies every component of the juvenile skeleton, by providing a detailed analysis of development and ageing and a detailed description of each bone in four ways: adult bone, early development, ossification and practical notes. New chapters and updated sections covering the dentition, age estimation in the living and bone histology. An updated bibliography documenting the research literature that has contributed to the field over the past 15 years since the publication of the first edition. Heavily illustrated, including new additions.
Current techniques used by forensic anthropologists for the identification of unknown human skeletal remains have largely been created using U.S. Black and White samples. When applied to Hispanics, these techniques perform poorly and can lead to misclassifications; consequently, there is an imperative need for population-specific standards for Hispanics. This research examines the classification accuracies obtained by the original Walker (Am J Phys Anthropol, 136, 2008) and Klales et al. (Am J Phys Anthropol, 149, 2012) methods for nonmetric sex estimation and provides recalibrated regression equations specifically for Hispanics. Ordinal data were collected for five skull and three pelvic traits from a sample of 54 modern Hispanic individuals. Recalibration of the Klales et al. equation improved accuracy (90.3% vs. 94.1%), while recalibration of the Walker method equation decreased accuracy (81.5% vs. 74.1%), but greatly improved sex bias (22.2% vs. -7.4%), thereby making the recalibrated equations more appropriate for use with Hispanics.