A multifaceted exploration of ontogenetic variation in vertebral neural canal size across contemporary populations

DATA AVAILABILITY STATEMENT : The data that support the findings of this study are openly available in the SVAD Zenodo Community repository at https://zenodo.org/communities/svad/ (DOI: 10.5281/zenodo.6342097).OBJECTIVES : Vertebral neural canal (VNC) dimensions are considered a reliable indicator of childhood stress. However, no study has characterized variation in VNC size or shape or the impact of extrinsic or intrinsic factors on their range of variation. The present study explores VNC dimensions of subadult samples varying in chronology, population of origin, geography, and socioeconomic backgrounds. MATERIALS AND METHODS : Antero-posterior (AP) and transverse (TR) diameters were measured on the tenth thoracic to the fifth lumbar vertebrae of 1404 contemporary individuals aged between birth and 22 years from Colombia (N = 28), France (N = 484), the Netherlands (N = 23), Taiwan (N = 31), and the United States (N = 838), and compared to lumbar diameters of subadults from the Spitalfields collection (N = 84) and the East Smithfield cemetery (N = 65). VNC variation was evaluated with skeletal growth profiles, principal component analyses (PCA), MANOVAs and ANOVAs. RESULTS : AP diameter growth ends during childhood, while TR diameter growth progressively slows before ending in adolescence. The Colombian sample presented the smallest VNC diameters compared to the other contemporary and historic samples. VNC shape (AP/TR ratio) was similar in contemporary samples. MANOVAs and ANOVAs revealed significant differences in VNC size according to country of origin and socio-economic status, primarily differentiating the Colombian sample. DISCUSSION : The overall consistency in size and shape among groups is remarkable. While physiological stress may contribute to variability in VNC size, intrinsic ontogenetic processes and other individual and environmental factors also influence variability in VNC size.National Institute of Justice and National Science Foundation.http://wileyonlinelibrary.com/journal/ajpa2023-12-09hj2023AnatomySDG-03:Good heatlh and well-bein

New insights on hip bone sexual dimorphism in adolescents and adults using deformation-based geometric morphometrics

Morphological variation of the human pelvis, and particularly the hip bone, mainly results from both female-specific selective pressure related to the give birth of large-headed newborns, and constraints in both sexes for efficient bipedal locomotion, abdominal stability, and adaptation to climate. Hip bone morphology has thus been extensively investigated using several approaches, although the nuances of inter-individual and sex-related variation are still underappreciated, and the effect of sex on ontogenetic patterns is debated. Here, we employ a landmark-free, deformation-based morphometric approach to explore variation in modern human hip bone shape and size from middle adolescence to adulthood. Virtual surface models of the hip bone were obtained from 147 modern human individuals (70 females and 77 males) including adolescents, and young and mature adults. The 3D meshes were registered by rotation, translation, and uniform scaling prior to analysis in Deformetrica. The orientation and amplitude of deviations of individual specimens relative to a global mean were assessed using Principal Component Analysis, while colour maps and vectors were employed for visualisation purposes. Deformation-based morphometrics is a time-efficient and objective method free of observer-dependent biases that allows accurate shape characterisation of general and more subtle morphological variation. Here, we captured nuanced hip bone morphology revealing ontogenetic trends and sex-based variation in arcuate line curvature, greater sciatic notch shape, pubic body and rami length, acetabular expansion, and height-to-width proportions of the ilium. The observed ontogenetic trends showed a higher degree of bone modelling of the lesser pelvis of adolescent females, while male variation was mainly confined to the greater pelvis

Mixed cumulative probit : a multivariate generalization of transition analysis that accommodates variation in the shape, spread and structure of data

DATA AVAILABITY STATEMENT: The data and analyses are all freely available. The data used in the current study are available in the Zenodo Subadult Virtual Anthropology Database Community: https://doi.org/10.5281/zenodo.5193208 [71]. The vignette is freely available here: https://rpubs.com/elainechu/mcp_vignette. The relevant code for this work is stored in GitHub: https://github.com/michaelholtonprice/rsos_mcp_intro and has been archived within the Zenodo repository: https://doi.org/10.5281/zenodo.7603754 [72].SUPPORTING INFORMATION: FILE S1: Supplemental material is hosted by figshare.Biological data are frequently nonlinear, heteroscedastic and conditionally dependent, and often researchers deal with missing data. To account for characteristics common in biological data in one algorithm, we developed the mixed cumulative probit (MCP), a novel latent trait model that is a formal generalization of the cumulative probit model usually used in transition analysis. Specifically, the MCP accommodates heteroscedasticity, mixtures of ordinal and continuous variables, missing values, conditional dependence and alternative specifications of the mean response and noise response. Cross-validation selects the best model parameters (mean response and the noise response for simple models, as well as conditional dependence for multivariate models), and the Kullback–Leibler divergence evaluates information gain during posterior inference to quantify mis-specified models (conditionally dependent versus conditionally independent). Two continuous and four ordinal skeletal and dental variables collected from 1296 individuals (aged birth to 22 years) from the Subadult Virtual Anthropology Database are used to introduce and demonstrate the algorithm. In addition to describing the features of the MCP, we provide material to help fit novel datasets using the MCP. The flexible, general formulation with model selection provides a process to robustly identify the modelling assumptions that are best suited for the data at hand.The National Institute of Justice and the National Science Foundation.https://royalsocietypublishing.org/journal/rsosAnatomySDG-03:Good heatlh and well-bein

Adéquation, répétabilité et reproductibilité de données ostéométriques obtenues sur os sec, sur des surfaces virtuelles d’os sec et sur des surfaces osseuses d’individus vivants

International audienc

Subadult Age Estimation Using the Mixed Cumulative Probit and a Contemporary United States Population

The mixed cumulative probit (MCP), a new, flexible algorithm that accommodates a variety of mean and shape parameters in univariate models and conditional dependence/independence in multivariate models, was used to develop subadult age estimation models. Sixty-two variables were collected on computed tomography (CT) images of 1317 individuals (537 females and 780 males) aged between birth and 21 years from the United States sample in the Subadult Virtual Anthropology Database (SVAD). Long bone measurements (n = 18), stages of epiphyseal fusion and ossification (n = 28), and stages of dental development of permanent teeth (n = 16) were used in univariate, multivariate, and mixed models and compared using test mean log posterior (TMNLP), root mean squared error (RMSE), and percent accuracy on an independent test sample. Out of the six possible parameter combinations, all combinations were accounted for at least once in the data and conditionally dependent models outperformed the conditionally independent models. Overall, multivariate models exhibited smaller TMNLP and RMSE, and an overall greater stability in the age estimations compared to univariate models across all ages and independent of indicator type. Pre-optimized subadult age estimation models are freely available for immediate application through MCP-S-Age, a graphical user interface

Standardizing ordinal subadult age indicators : testing for observer agreement and consistency across modalities

Skeletal and dental data for subadult analyses obtained from dry bones or various types of medical images, such as computed tomography (CT) scans or conventional radiographs/x-rays, should be consistent and repeatable to ensure method applicability across modalities and support combining study samples. The present study evaluates observer agreement of epiphyseal fusion and dental development stages obtained on CT scans of a U.S. sample and the consistency of epiphyseal fusion stages between CT scans and projected scan radiographs/scout images (U.S. CT sample), and between dry bones and conventional x-rays (Colombian osteological sample). Results show that both intra- and interobserver agreements of scores on CT scans were high (intra: mean Cohen’s kappa = 0.757–0.939, inter: mean Cohen’s kappa = 0.773–0.836). Agreements were lower for dental data (intra: mean Cohen’s kappa = 0.757, inter: mean Cohen’s kappa = 0.773–0.0.820) compared to epiphyseal fusion data (intra: mean Cohen’s kappa = 0.939, inter: mean Cohen’s kappa = 0.807–0.836). Consistency of epiphyseal fusion stages was higher between dry bones and conventional x-rays than between CT scans and scout images (mean Cohen’s kappa = 0.708–0.824 and 0.726–0.738, respectively). Differences rarely surpassed a one-stage value between observers or modalities. The complexity of some ossification patterns and superimposition had a greater negative impact on agreement and consistency rates than observer experience. Results suggest ordinal subadult skeletal data can be collected and combined across modalities.The National Institute of Justice and the National Science Foundation.http://www.elsevier.com/locate/forsciint2022-01-10hj2021Anatom

A comparison of subadult skeletal and dental development based on living and deceased samples

OBJECTIVES : A fundamental assumption in biological anthropology is that living individuals will present with different growth than non‐survivors of the same population. The aim is to address the question of whether growth and development data of non‐survivors are reflective of the biological consequences of selective mortality and/or stress. MATERIALS AND METHODS : The study compares dental development and skeletal growth collected from radiographic images of contemporary samples of living and deceased individuals from the United States (birth to 20 years) and South Africa (birth to 12 years). Further evaluation of deceased individuals is used to explore differential patterns among manners of death (MOD). RESULTS: Results do not show any significant differences in skeletal growth or dental development between living and deceased individuals. However, in the South African deceased sample the youngest individuals exhibited substantially smaller diaphyseal lengths than the living sample, but by 2 years of age the differences were negligible. In the US sample, neither significant nor substantial differences were found in dental development or diaphyseal length according to MOD and age (>2 years of age), though some long bones in individuals <2 years of age did show significant differences. No significant differences were noted in diaphyseal length according to MOD and age in the SA sample. DISCUSSION : The current findings refute the idea that contemporary deceased and living individuals would present with differential growth and development patterns through all of ontogeny as well as the assumptions linking short stature, poor environments, and MOD.Directorate for Biological Sciences and National Institute of Justice.https://wileyonlinelibrary.com/journal/ajpa2021-11-27hj2021Anatom

The importance of processing procedures and threshold values in CT scan segmentation of skeletal elements: An example using the immature os coxa

As the accessibility and utility of virtual databases of skeletal collections continues to grow, the impact that scan processing procedures has on the accuracy of data obtained from virtual databases remains relatively unknown. This study quantifies the intra- and inter-observer error generated from varying computed tomography (CT) scan processing protocols, including re-segmentation, incrementally varying thresholding value, and data collectors’ selection of the threshold value on a set of virtual subadult pelves. Four observers segmented the subadult ossa coxarum from postmortem CT scans of the fully-fleshed bodies of eleven individuals of varying ages. Segmentation protocol was set, with the exception of each observer selecting their own thresholding value for each scan. The resulting smoothed pelvic surfaces were then compared using deviation analyses. Root mean square error (RMSE), average distance deviation, and maximum deviation distances demonstrated that thresholding values of ∼50 HU (Hounsfield units) are easily tolerated, the surfaces generated are robust to error, and threshold value selection does not systematically vary with user experience. The importance of consistent methodology during segmentation protocol is highlighted here, especially with regards to consistency in both selected thresholding value as well as smoothing protocol, as these variables can affect subsequent measurements of the resultant surfaces