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Osteoporosis in postmenopausal women is one of the causes of femoral fractures and is prevented by the administration of bisphosphonates. Individual morphologies are considered to increase the risk of atypical fractures associated with long-term administration. To evaluate cortical bone morphology quantitatively, we established a method to measure the distance from the center point of a cross-section to the external and internal borders based on CT images. Using this method, 44 sides of a female femoral skeleton specimen were examined and areas of protrusion and thickening in the medial anterior and lateral posterior regions just below the lesser trochanter were identified. These positions strongly correlated with the anteversion angle, suggesting the involvement of the distribution of the load received from body weight defined by the angle. The finite element method was used to examine the relationships between the positions of these areas with compressive and tensile stress distribution areas in the one-legged standing condition. The medial anterior region and lateral posterior region protruded and thickened in response to compressive and tensile stress, respectively. In addition, a hierarchical relationship was observed between the anteversion angle, tensile stress distribution, protrusion, and thickening in femurs with thinning of cortical bone, indicating that morphogenesis occurs adaptively to loading. The present results demonstrate the usefulness of this method in considering the formation mechanism and function of the femoral diaphysis and suggest that bone remodeling is necessary to maintain adaptability., (© 2024 Orthopaedic Research Society.)

Objective: Chimpanzees are altricial in terms of their locomotor development and transition from being carried to engaging in suspensory and arboreal locomotor behaviors to eventually relying on terrestrial quadrupedalism as their main form of locomotion. Here, we consider the mechanical implications of femoral cortical bone restructuring during growth and locomotor development in wild chimpanzees., Materials and Methods: Cortical bone structure was examined in an ontogenetic sample of wild chimpanzees from a single subspecies (P. t. verus) spanning in age from 2 weeks to 12.6 years. Diaphyseal cross-sections were extracted from micro-CT scans of the femur at 35%, 50%, and 65% of total intermetaphyseal length and variation in cortical bone structure was assessed based on bending rigidity (Imax/Imin, Ix/Iy), relative medullary area, and cortical bone porosity., Results: Diaphyseal shape is relatively circular with a high amount of cortical bone porosity and a large relative medullary area during early infancy. Distinct shifts in cortical bone structure occurred for each studied parameter with the biggest changes occurring within the first 5 years. Values appear to stabilize as quadrupedal walking increases in frequency and is established as the main form of locomotion., Discussion: Collectively, the results suggest a degree of integration in which cortical bone restructures in response to rapid changes in locomotion in addition to nonmechanical influences such as hormonal, and growth factors, without compromising function and structural integrity. The extent of influence of each factor varies throughout growth and highlights the need for caution in functional interpretations of cortical bone geometry., (© 2024 The Author(s). American Journal of Biological Anthropology published by Wiley Periodicals LLC.)

Geometric morphometrics (GMM) have been applied to understand morphological variation in biological structures. However, research studying cortical bone through geometric histomorphometrics (GHMM) is scarce. This research aims to develop a landmark-based GHMM protocol to depict osteonal shape variation in the femoral diaphysis, exploring the role of age and biomechanics in bone microstructure. Proximal, midshaft, and distal anatomical segments from the femoral diaphysis of six individuals were assessed, with 864 secondary intact osteons from eight periosteal sampling areas being manually landmarked. Observer error was tested using Procrustes ANOVA. Average osteonal shape and anatomical segment-specific variation were explored using principal component analysis. Osteon shape differences between segments were examined using canonical variate analysis (CVA). Sex differences were assessed through Procrustes ANOVA and discriminant function analysis (DFA). The impact of osteonal size on osteonal shape was investigated. High repeatability and reproducibility in osteon shape landmarking were reported. The average osteon shape captured was an elliptical structure, with PC1 reflecting more circular osteons. Significant differences in osteon shape were observed between proximal and distal segments according to CVA. Osteon shape differed between males and females, with DFA showing 52% cross-validation accuracies. No effect of size on shape was reported. Osteonal shape variation observed in this study might be explained by the elderly nature of the sample as well as biomechanical and physiological mechanisms playing different roles along the femoral diaphysis. Although a larger sample is needed to corroborate these findings, this study contributes to the best of our knowledge on human microanatomy, proposing a novel GHMM approach., (© 2024 The Author(s). Journal of Forensic Sciences published by Wiley Periodicals LLC on behalf of American Academy of Forensic Sciences.)

The increased limb bone density documented previously for aquatic tetrapods has been proposed to be an adaptation to overcome buoyancy during swimming and diving. It can be achieved by increasing the amount of bone deposition or by reducing the amount of bone resorption, leading to cortical thickening, loss of medullary cavity, and compaction of trabecular bone. The present study examined the effects of locomotor habit, body size, and phylogeny on the densitometric, cross-sectional, and biomechanical traits of femoral diaphysis and neck in terrestrial, semiaquatic, and aquatic carnivores, and in terrestrial and semiaquatic rodents (12 species) by using peripheral quantitative computed tomography, three-point bending, and femoral neck loading tests. Groupwise differences were analyzed with the univariate generalized linear model and the multivariate linear discriminant analysis supplemented with hierarchical clustering. While none of the individual features could separate the lifestyles or species adequately, the combinations of multiple features produced very good or excellent classifications and clusterings. In the phocid seals, the aquatic niche allowed for lower femoral bone mineral densities than expected based on the body mass alone. The semiaquatic mammals mostly had high bone mineral densities compared to the terrestrial species, which could be considered an adaptation to overcome buoyancy during swimming and shallow diving. Generally, it seems that different osteological properties at the levels of mineral density and biomechanics could be compatible with the adaptation to aquatic, semiaquatic, or terrestrial niches., (© 2024. The Author(s).)

Objectives: This study tests if femoral and humeral cross-sectional geometry (CSG) and cross-sectional properties (CSPs) in an ontogenetic series of wild-caught chimpanzees (Pan troglodytes ssp.) reflect locomotor behavior during development. The goal is to clarify the relationship between limb bone structure and locomotor behavior during ontogeny in Pan., Materials and Methods: The latex cast method was used to reconstruct cross sections at the midshaft femur and mid-distal humerus. Second moments of area (SMAs) (I x , I y , I max , I min ), which are proportional to bending rigidity about a specified axis, and the polar SMA (J), which is proportional to average bending rigidity, were calculated at section locations. Cross-sectional shape (CSS) was assessed from I x /I y and I max /I min ratios. Juvenile and adult subsamples were compared., Results: Juveniles and adults have significantly greater femoral J compared to humeral J. Mean interlimb proportions of J are not significantly different between the groups. There is an overall decreasing trend in diaphyseal circularity between the juvenile phase of development and adulthood, although significant differences are only found in the humerus., Discussion: Juvenile chimpanzee locomotion includes forelimb- and hindlimb-biased behaviors. Juveniles and adults preferentially load their hindlimbs relative to their forelimbs. This may indicate similar locomotor behavior, although other explanations including a diversity of hindlimb-biased locomotor behaviors in juveniles cannot be ruled out. Different ontogenetic trends in forelimb and hindlimb CSS are consistent with limb bone CSG reflecting functional adaptation, albeit the complex nature of bone functional adaptation requires cautious interpretations of skeletal functional morphology from biomechanical analyses., (© 2024 Wiley Periodicals LLC.)

Sex estimation equations are population-specific, and a wider use of multiple bones to generate equations will increase the accuracy of sex estimation in forensic settings. The metatarsal bones have been used previously, however the dimensions around the diaphyseal nutrient foramen have not been utilised in sex estimation. The current study aimed to determine the utility of the dimensions around the nutrient foramen of metatarsal bones in estimating sex in the South Africans of European descent (SAED). Five measurements around the nutrient foramen were taken from a total of 876 metatarsal bones (first to fifth) from 186 individual skeletons (99 males, 87 females) obtained from the Raymond A. Dart Modern Skeletal Collection. Measurements subjected to direct and stepwise discriminant function (DFA) and logistic regression (LRA) analyses included total length, distance from proximal end to nutrient foramen, circumference, and mediolateral and dorsoplantar diameters at the level of the nutrient foramen. The original classification accuracies for multivariable functions of the stepwise and direct DFA ranged from 83.1-88.3% to 85.5-88.3%, respectively. The original classification accuracies for multivariable functions of the stepwise and direct LRA ranged from 83.3%-88.7% to 86.2%-88.3%, respectively. The cross-validation classifications showed a drop of 0-2.4% for DFA and 0.2-1.1% for LRA. The width measurements were better predictors of sex than length. The dimensions around the metatarsal bone nutrient foramen exhibit sexual dimorphism in the SAED. The generated DFA and LRA functions produced high average classification accuracies which are useful in sex estimation during forensic human identification., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

We discuss several variants of the metaphyseal and diaphyseal bone surfaces that may be misleading in clinical practice. They include metaphyseal stripes, spiculated metaphyseal cortex, cortical desmoid, laminated lateral supracondylar ridge, cortical vascular canals, variations in shape or lucency of normal tuberosities, cortical thickening of normal ridges, and well-organized undulated hyperostosis at the proximal phalanges., Competing Interests: None declared., (Thieme. All rights reserved.)

Objectives: The study of growth in the past is a critical component of bioarcheological analyses. However, our understanding of growth in the past is subject to a number of methodological challenges. This study aims to model the skeletal growth of past populations by considering the challenges associated with the data collection process and the challenges associated with the age estimation procedures., Materials and Methods: We use skeletal remains from two historic African American cemeteries in the American South to model femoral diaphyseal length-for-age. We estimate the age of each individual using dental development techniques and present growth curves as both a product of the maximum likelihood (MLE) age estimate and the estimated posterior age distribution. Growth was compared against a reference sample from the University of Colorado Child Research Council Study., Results: The results of our analyses showed that femoral diaphyseal length in two historic African American communities is small-for-estimated age as compared to a modern reference sample. However, the magnitude and characterization of this difference is variable when taking into account the broader posterior age distribution., Discussion: Both samples may be small-for-age due to physiological stress associated with racism, inequality, and the compounding effects of early urbanization. However, the interpretation of growth in the past is muddled when considering the relationship between the study sample and the reference sample, when accounting for uncertainty in the age estimation procedure, and the error-inducing steps taken during the data collection process. Future interpretation of skeletal growth in the past must include a full account of the possible sources of error in order to present an accurate representation of growth., (© 2021 Wiley Periodicals LLC.)

Objectives: This study compares lower limb diaphyseal robusticity between Native Alaskan hunter-gatherers to reconstruct patterns of mobility and engagement with terrain., Materials and Methods: Ancestral remains included in this study date between 600 and 1800 C.E. and were divided into three regions: Coastal Bay, Far North Coastal, and Inland/Riverine. Cross-sectional properties were determined at femoral and tibial midshafts and standardized by powers of body mass and bone length., Results: Consistently elaevated areas and second moments of area were found in ancestral remains from the Far North Coastal, while the Coastal Bay remains had reduced diaphyseal robusticity. Individuals from the Inland/Riverine region were intermediate in robusticity for male femora, but similar to the Coastal Bay group for females. Sexual dimorphism was greatest in the Inland/Riverine ancestral remains and comparable between Coastal Bay and Far North Coastal regions., Conclusions: Ancestral remains from the Far North Coastal region have the greatest diaphyseal robusticity in response to intensive hunting and travel over rugged terrain. Reduced sexual dimorphism in the Far North Coastal region suggest female participation in hunting activities. Intermediate diaphyseal robusticity among Inland/Riverine males and increased sexual dimorphism reflects diverse patterns of mobility in relation to the hunting cycle between males and females. Reduced diaphyseal robusticity and sexual dimorphism among the Coastal Bay group is associated with sedentary villages established around net fishing in regions with low relief. Such findings argue against technocentric views of sedentism in hunter-gatherer lifeways and generally reflect diverse adaptive strategies and interaction with local terrain among Indigenous Late Holocene hunter-gatherers of Alaska., (© 2021 Wiley Periodicals LLC.)

The diaphysis of the human femoral bone has a physiological anterior curvature; additionally, there is a curvature to the medial side or lateral side. In addition to compression stress from gravity during standing, walking, and running, these bones are continuously exposed to complex stresses from the traction forces of the various strong muscles attached to them. The femoral diaphysis is subjected to these mechanical stresses, and the direction and size of its curvature are defined according to Wolff's law and the mechanostat theory of Frost. The purpose of this study was to quantitatively evaluate the curvature of the femoral diaphysis in Japanese skeletons by determining the curve connecting the central mass distributions (CMD) of cross-sectional images. A total of 90 right femora (46 males and 44 females) were randomly selected from modern Japanese skeletal specimens. Full-length images of these bones were acquired using a clinical computed tomography scanner. The range between the lower end of the lesser trochanter and the adductor tubercle of each femur was divided at regular intervals to obtain ten planes, and nine levels were analyzed. The CMD curve was determined by connecting the CMDs of each of the nine cross-sections. First, the CMD of a cross-section in each of the nine slices was calculated, and the nine trajectories were superimposed from above. Then, by converting the shape of the entire CMD curve to superimpose the coordinates of the endpoint on the starting point, a closed arc representing the curvature of the femur was determined. For both males and females, the patterns varied from mostly medial to largely lateral curvature. The size of the curvature also varied for individuals. By analyzing only the coordinates of the vertex of the CMD curve of each femoral bone, the outlines of the diaphyseal curvatures could be recognized. The femora were thereby divided into two groups: medial bending and lateral bending. Considering males and females together, the number in the lateral-curvature group (n = 51) was larger than that in the medial-curvature group (n = 39). Moreover, the average age of the lateral-curvature group was significantly higher than that of the medial-curvature group (p < 0.05). In males, with an increase in the cortical bone proportion of the cross-sectional area, the anterior vertex of diaphyseal bending tended to be more prominent. This cortical proportion was significantly higher in the medial-curvature groups than in the lateral-curvature group (p < 0.01). The phenomena observed in this study may be related to pathophysiologies such as atypical fractures of the femur and osteoarthritis of the knee joints., (© 2021 Anatomical Society.)

Purpose: Physical activity benefits bone mass and cortical bone size. The current study assessed the impact of chronic (≥10 yr) physical activity on trabecular microarchitectural properties and microfinite element analyses of estimated bone strength., Methods: Female collegiate-level tennis players (n = 15; age = 20.3 ± 0.9 yr) were used as a within-subject controlled model of chronic unilateral upper-extremity physical activity. Racquet-to-nonracquet arm differences at the distal radius and radial diaphysis were assessed using high-resolution peripheral quantitative computed tomography. The distal tibia and the tibial diaphysis in both legs were also assessed, and cross-country runners (n = 15; age = 20.8 ± 1.2 yr) included as controls., Results: The distal radius of the racquet arm had 11.8% (95% confidence interval [CI] = 7.9% to 15.7%) greater trabecular bone volume/tissue volume, with trabeculae that were greater in number, thickness, connectivity, and proximity to each other than that in the nonracquet arm (all P < 0.01). Combined with enhanced cortical bone properties, the microarchitectural advantages at the distal radius contributed a 18.7% (95% CI = 13.0% to 24.4%) racquet-to-nonracquet arm difference in predicted load before failure. At the radial diaphysis, predicted load to failure was 9.6% (95% CI = 6.7% to 12.6%) greater in the racquet versus nonracquet arm. There were fewer and smaller side-to-side differences at the distal tibia; however, the tibial diaphysis in the leg opposite the racquet arm was larger with a thicker cortex and had 4.4% (95% CI = 1.7% to 7.1%) greater strength than the contralateral leg., Conclusion: Chronically elevated physical activity enhances trabecular microarchitecture and microfinite element estimated strength, furthering observations from short-term longitudinal studies. The data also demonstrate that tennis players exhibit crossed symmetry wherein the leg opposite the racquet arm possesses enhanced tibial properties compared with in the contralateral leg., (Copyright © 2020 by the American College of Sports Medicine.)

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., (© 2020 Wiley Periodicals LLC.)

This paper introduces an automated method for estimating sex from the lower and upper limbs based on diaphyseal CSG properties. The proposed method was developed and evaluated using 389 femurs, 412 tibias, and 404 humeri of adult individuals from a modern Greek reference sample, the Athens Collection. The skeletal properties, which were extracted with the CSG-Toolkit, were analyzed with step-wise DFA (evaluated with LOOCV) and subsequently with RBF kernel SVM supervised learning. SVM cross-validation was based on a 20-fold stratified random sample splitting as well as a chronological split based on year of birth to further assess the effect of secular change in sex estimation capacity. Maximum cross-validated classification accuracy from step-wise DFA reached 94.8% for the femur, 94.7% for the tibia, and 97.3% for the humerus, whereas SVM cross-validated results were similar although slightly lower, mainly due to the more strict cross-validation scheme. Our results suggest that the proposed sex estimation method is reasonably robust to secular change, since there was limited loss in classification accuracy between different chronological groups, despite the presence of secular change in stature of the Greek population during the examined period. The proposed method has been implemented as a function for the GNU Octave environment, named estimate&#95;sex, which comprises a self-intuitive graphical user interface for facilitating sex estimation and is freely available under a suitable license.

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., Competing Interests: Conflict of interest The authors have no competing interests., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Objective: This study investigates bilateral asymmetry in the humerus of modern human populations with differing activity patterns to assess the relative plasticity of different bone regions in response to environmental influences, particularly the biomechanical demands of handedness., Methods: External breadths, cross-sectional properties, and centroid sizes were used to quantify directional and absolute asymmetry of humeral diaphyseal, distal periarticular, and articular regions in six populations with differing subsistence strategies (total n = 244). Geometric section properties were measured using computed tomography at six locations along the distal humerus, while centroid sizes of the distal articular and periarticular regions, as well as eight segments of the diaphysis, were extracted from external landmark data. Bilateral asymmetries were compared between populations and sexes. Each property was also tested for correlation with bilateral asymmetry at 40% of bone length, which has been shown to correlate with handedness., Results: Asymmetry is highest in the diaphysis, but significant through all distal bone regions. Asymmetry increases in the region of the deltoid tuberosity, and progressively declines distally through the shaft and distal periarticular region. Articular asymmetry is higher than periarticular asymmetry, approaching levels seen just proximal to the olecranon fossa, and is weakly but significantly correlated with diaphyseal asymmetry. Hunter-gatherers from Indian Knoll have significantly higher levels of asymmetry than other groups and are more sexually dimorphic, particularly in cross-sectional properties of the diaphysis., Conclusions: Humeral dimensions throughout the diaphysis, including regions currently used in taxonomic assignments of fossil hominins, likely respond to in vivo use, including population and sex-specific behaviors., (© 2021 Wiley Periodicals LLC.)

Long bones comprise articular ends (epiphyses) joined by transitional metaphyses and a diaphysis (shaft). The structure of the latter is often viewed as regularly tubular across tetrapods (limbed vertebrates). However, assessments of the bone structure along the whole diaphysis are rare. Here, I assess whole-diaphysis profiles of global compactness (bone fraction) of 164 species of extant and extinct therian mammals (marsupials + placentals) in a phylogenetically informed context. Generally terrestrial, mammals have acquired multiple times the highly specialized aerial, fully aquatic, and subterranean lifestyles, allowing to potentially associate specific traits with these lifestyles. I show that there is a consistent increase in global compactness along the diaphysis in most mammals. This pattern is modified in a limited number of specialized species: all aerial clades (gliders and bats) have rather uniform and low values, while cetaceans' humeral diaphysis is marked by a slightly more compact mid-diaphyseal region. Among subterranean clades, structure alterations are most obvious in fossorial talpids (true moles) and their highly modified humerus. These results call for the investigation of bone structure in whole skeletal elements of key fossils in order to reconstruct the patterns of evolutionary modifications associated with lifestyle transitions., (© 2021 The Authors. Evolution published by Wiley Periodicals LLC on behalf of The Society for the Study of Evolution.)

Objectives: Many primates change their locomotor behavior as they mature from infancy to adulthood. Here we investigate how long bone cross-sectional geometry in Pan, Gorilla, Pongo, Hylobatidae, and Macaca varies in shape and form over ontogeny, including whether specific diaphyseal cross sections exhibit signals of periosteal adaptation or canalization., Materials and Methods: Diaphyseal cross sections were analyzed in an ontogenetic series across infant, juvenile, and adult subgroups. Three-dimensional laser-scanned long bone models were sectioned at midshaft (50% of biomechanical length) and distally (20%) along the humerus and femur. Traditional axis ratios acted as indices of cross-sectional circularity, while geometric morphometric techniques were used to study cross-sectional allometry and ontogenetic trajectory., Results: The humeral midshaft is a strong indicator of posture and locomotor profile in the sample across development, while the mid-femur appears more reflective of shifts in size. By comparison, the distal diaphyses of both limb elements are more ontogenetically constrained, where periosteal shape is largely static across development relative to size, irrespective of a given taxon's behavior or ecology., Discussion: Primate limb shape is not only highly variable between taxa over development, but at discrete humeral and femoral diaphyseal locations. Overall, periosteal shape of the humeral and femoral midshaft cross sections closely reflects ontogenetic transitions in behavior and size, respectively, while distal shape in both bones appears more genetically constrained across intraspecific development, regardless of posture or size. These findings support prior research on tradeoffs between function and safety along the limbs., (© 2020 Wiley Periodicals LLC.)

Objectives: The paleontological description and comparative analysis using discrete morphology, morphometrics (linear and geometric) and cross-sectional geometry of three femoral diaphyseal sections from the Middle Pleistocene site of Hualongdong, China., Materials and Methods: The material consists of the original Hualongdong femoral fossils and available data on femoral diaphyses from Middle and Late Pleistocene archaic humans and Middle and earlier Upper Paleolithic modern humans. The methods include visual observation, diaphyseal diameters, cross-sectional parameters (transverse areas and second moments of area derived from micro-CT scans), and geometric morphometrics using semilandmark data., Results: The Hualong 11 midshaft section is similar to other Middle and Late Pleistocene archaic humans in being transversely broad and lacking a pilaster despite a prominent linea aspera. It clusters principally with archaic human femora in all measured parameters. The Hualong 15 and 16 subtrochanteric pieces are similar to many Middle Pleistocene and early modern human femora in being transversely broad. In particular, Hualong 15 exhibits a prominent lateral (gluteal) buttress, similar to many Upper Paleolithic femora but also the Lazaret and Krapina archaic ones. In addition, Hualong 15 has a small third trochanter, a common Upper Paleolithic but rare earlier feature., Discussion: The Hualong 11 femoral piece reinforces the general Middle Pleistocene pattern, especially for eastern Eurasia from which archaic human femora are rare. The subtrochanteric proportions of Hualong 15 and 16 reinforce the Early Pleistocene and (generally) Middle Pleistocene pattern of bone distributions, but their subperiosteal contours align them (along with those of the Lazaret and Krapina femora) with Upper Paleolithic ones. It is difficult to account for these proportions from the generally broad pelves of Pleistocene archaic humans., (© 2020 Wiley Periodicals LLC.)

This study investigated cross-sectional morphological differences in the diaphysis of the third metacarpal bone (MC3) between prehistoric Jomon hunter-gatherers and modern Japanese people. Overall, 179 skeletal remains of 119 individuals (73 men and 46 women) from the Middle-to-Final Jomon period (3500 BC-500 BC) and 60 modern Japanese people (35 men and 25 women) were included in the analysis. Analyses were performed at the mid-shaft of the MC3 using linear measurement, elliptic Fourier analysis, and cross-sectional geometric properties. The standardized polar section modulus (Z pSTD ) indicated sexual differences in both populations. The right MC3 was generally stronger than the left side. There was no populational difference in the Z pSTD in both sexes. In both men and women, the cross-sectional shape of the MC3 was relatively larger in the dorso-palmar direction than in the radioulnar direction in the Jomon population compared to the modern Japanese population. Sexual differences in cross-sectional shape were recognized only in the Jomon population, with the dorso-palmar elongation being greater in Jomon men than in women (particularly when comparing the left MC3). There was a significant side difference in the diaphyseal shape among Jomon women, with the right MC3 being relatively larger in the dorso-palmar direction. These findings were consistent, although skeletal remains of the Jomon population were excavated from different regions. Differences in the diaphyseal cross-sectional shape between populations suggest differences in habitual loading on MC3 associated with differences in subsistence behavior. Furthermore, differences in diaphyseal shape and strength between Jomon men and women suggest sexual division of labor, with men performing bimanual tasks and women performing unimanual tasks.

Objectives: This study describes and demonstrates the functionalities and application of a new R package, morphomap, designed to extract shape information as semilandmarks in multiple sections, build cortical thickness maps, and calculate biomechanical parameters on long bones., Methods: morphomap creates, from a single input (an oriented 3D mesh representing the long bone surface), multiple evenly spaced virtual sections. morphomap then directly and rapidly computes morphometric and biomechanical parameters on each of these sections. The R package comprises three modules: (a) to place semilandmarks on the inner and outer outlines of each section, (b) to extract cortical thicknesses for 2D and 3D morphometric mapping, and (c) to compute cross-sectional geometry., Results: In this article, we apply morphomap to femora from Homo sapiens and Pan troglodytes to demonstrate its utility and show its typical outputs. morphomap greatly facilitates rapid analysis and functional interpretation of long bone form and should prove a valuable addition to the osteoarcheological analysis software toolkit., Conclusions: Long bone loading history is commonly retrodicted by calculating biomechanical parameters such as area moments of inertia, analyzing external shape and measuring cortical thickness. morphomap is a software written in the open source R environment, it integrates the main methodological approaches (geometric morphometrics, cortical morphometric maps, and cross-sectional geometry) used to parametrize long bones., (© 2020 The Authors. American Journal of Physical Anthropology published by Wiley Periodicals LLC.)

Objectives: Fibular structure is related to locomotor behavior, which allows an exploration of mobility in past human populations with diaphyseal cross-sectional geometry (CSG). However, bone structure depends on age-related changes. Nonmechanical alterations can affect biomechanical investigations. In this study, we examined how the cortical area and the variables used as functional markers in the fibular diaphysis (i.e., CSG and furrows) change with aging. We predict classic and specific modifications, and we discuss functional interpretations based on bone structure., Materials and Methods: The sample consisted of 124 individuals of known age in whom the fibular furrow depths were measured with calipers. Microcomputed tomography (micro-CT) scanning of 38 individuals provided CSG (e.g., cortical area, shape index, and robusticity) and fibular furrow indices. CSG was studied at five cross sections taken along the diaphysis. Linear regression analyses and age group comparisons were conducted., Results: The cross-sectional shape summary by fibular furrows and shape index and the total area did not change with aging; in contrast, the cortical area and the robusticity (Z p -std) decreased with age., Discussion: The decrease in robusticity (Z p -std) with aging is due to the maintenance of total area, which is related to the specific mechanical environment of the fibula, and to the loss of cortical bone and not to the decrease in mechanical stress. This finding is consistent with the lower bone modeling capacity in aged individuals, which also explains the lack of significant changes in the diaphyseal shape. Thus, fibular structure in older individuals is due to a combination of early bone adaptations to stress and aging effects., (© 2020 Wiley Periodicals LLC.)

Objectives: This study examines long bone diaphyseal rigidity and shape of hunter-gatherers at Roonka to make inferences about subsistence strategies and mobility of inhabitants of semi-arid southeastern Australia. Roonka is a cemetery site adjacent to the Lower Murray River, which contains over 200 individuals buried throughout the Holocene. Archaeological evidence indicates that populations living near this river corridor employed mobile, risk averse foraging strategies., Methods: This prediction of lifestyle was tested by comparing the cross-sectional geometric properties of the humerus, radius, ulna, femur, tibia, and fibula of individuals from Roonka to samples of varying subsistence strategies. Bilateral asymmetry of the upper limb bones was also examined., Results: Roonka males and females have moderately high lower limb diaphyseal rigidity and shape. In the upper limb, females have low rigidity and bilateral asymmetry while males have moderately high rigidity and bilateral asymmetry. This pattern is similar to other foraging groups from Australia and southern Africa that have behaviorally adapted to arid and semi-arid environments., Discussion: Lower limb results suggest that populations in the Lower Murray River Valley had relatively elevated foraging mobility. Upper limb rigidity and bilateral asymmetry indicate a sexual division of labor at Roonka. Females resemble other samples that had mixed subsistence strategies that involved hunting, gathering, and processing tasks. Males display a pattern similar to groups that preferentially hunted large game, but that supplemented this source with smaller game and riverine resources., (© 2020 Wiley Periodicals, Inc.)

Objectives: South African Africans have been reported to have experienced negative or null secular trends in stature and other measures of skeletal structure across the 19th and 20th centuries, presumably due to poor living conditions during a time of intensifying racial discrimination. Here, we investigate whether any secular trend is apparent in limb bone strength during the same period., Materials and Methods: Cadaver-derived skeletons (n = 221) were analyzed from female and male South African Africans who were born between 1839 and 1970, lived in and around Johannesburg, and died between 1925 and 1991 when they were 17-90 years of age. For each skeleton, a humerus and femur were scanned using computed tomography, and mid-diaphyseal cross-sectional geometric properties were calculated and scaled according to body size., Results: In general linear mixed models accounting for sex, age at death, and skeletal element, year of birth was a significant (p < .05) negative predictor of size-standardized mid-diaphyseal cortical area (a proxy for resistance to axial loading) and polar moment of area (a proxy for resistance to bending and torsion), indicating a temporal trend toward diminishing limb bone strength. No significant interactions were detected between year of birth and age at death, suggesting that the decline in limb bone strength was mainly due to changes in skeletal maturation rather than severity of age-related bone loss., Discussion: Limb bone strength is thus potentially another feature of the skeletal biology of South African Africans that was compromised by poor living conditions during the 19th and 20th centuries., (© 2020 Wiley Periodicals, Inc.)

Introduction: Cortical thickness of the femoral diaphysis is assumed to be a preferred parameter in the assessment of the structural adaptation by mechanical use and biological factors. This study aimed to investigate the age- and sex-specific characteristics in cortical thickness of the femoral diaphysis between young and elderly non-obese people., Materials and Methods: This study investigated 34 young subjects (21 men and 13 women; mean age: 27 ± 8 years) and 52 elderly subjects (29 men and 23 women; mean age: 70 ± 6 years). Three-dimensional (3D) cortical thickness of the femoral diaphysis was automatically calculated for 5000-8000 measurement points using the high-resolution cortical thickness measurement from clinical CT data. In 12 assessment regions created by combining three heights (proximal, central, and distal diaphysis) and four areas of the axial plane at 90° (medial, anterior, lateral, and posterior areas) in the femoral coordinate system, the standardized thickness was assessed using the femoral length., Results: As per the trends, (1) there were no differences in medial and lateral thicknesses, while the posterior thickness was greater than the anterior thickness, (2) the thickness in men was higher than that in women, and (3) the thickness in young subjects was higher than that in elderly subjects., Conclusions: The results of this study are of clinical relevance as reference points to clarify the causes of various pathological conditions for diseases of the lower extremities.

The nutrient arteries, located in the long bone diaphysis, are the major blood supply to long bones, especially during the early phases of growth and ossification. Their intersection with the central axis of the medullary area corresponds to the ossification center, and their opening on the outer bone surface to the nutrient foramen. Nutrient arteries/foramen have essentially been analyzed in humans, and only to a much lesser extent in a few mammals. Some studies have taken measurements of the nutrient foramen; others have investigated the shape and orientation of the nutrient canals, although only partially. No studies have analyzed the nutrient canal in three dimensions inside the bone and the relationships between nutrient foramen, nutrient canal, growth, and physiology require further investigation. The current study proposes to investigate in three dimensions the shape of the nutrient canal in stylopod bones of various mammals. Qualitative and quantitative parameters are defined to discuss the diversity in, for example, morphology, orientation, and diameter encountered, resorting to two different datasets to maximize differences within mammals and then analyze variation within morphologically and phylogenetically closer taxa. This study highlights a strong intraspecific variation for various parameters, with limited biological signal, but also shows trends. It notably provides evidence that canals are generally more numerous and relatively thinner in less elongated bones. Moreover, it shows that the growth center is located distally in the humerus and proximally in the femur, and that the canals are essentially oriented towards the faster growing end, so that the nutrient foramen does not indicate the location of the growth center. This result seems general in mammals but cannot be generalized outside of Mammalia. Further analyses of the features of nutrient arteries in reptiles are required to make comparisons with the trends observed in mammals., (© 2019 Anatomical Society.)

Introduction: Although pre-Hispanic hunter-gatherer and horticulturalist (known as Guaraní) societies from the lower Paraná River Delta (Argentina) presented differences in diet, pottery decoration, mortuary practices, and places of origin, differences in skeletal morphology between such groups have never been systematically explored. This work focuses on variations in humeral and femoral external linear measurements and derived structural properties of adult individuals from both societies as well as on variations in body mass and stature., Materials and Methods: Bone length, epiphyseal size, and midshaft breadth were measured in 82 adult humeri and 100 femora from hunter-gatherer and Guaraní archeological sites. Epiphyseal and midshaft robusticity, residual strength, midshaft shape and area, stature, and body mass were then estimated. Mann-Whitney tests were run to compare the hunter-gatherer and Guaraní samples., Results: Male Guaraní individuals presented stronger humeri and more robust femoral and humeral proximal epiphyses than hunter-gatherers. In addition, female Guaraní individuals showed rounder femoral diaphyses in comparison with female hunter-gatherers. Concerning stature, the Guaraní individuals were found to be shorter than hunter-gatherers, regardless of sex. No statistical differences were found in body mass., Discussion: Despite the fact that skeletal variations between Guaraní and hunter-gatherers could be a consequence of differences in mechanical loadings and genetic composition, bone robusticity is also positively correlated with increased age, but as the age composition of the Guaraní sample could not be estimated, skeletal variation between the samples could be a consequence of differences in age distribution., (© 2019 Wiley Periodicals, Inc.)

The abundant femoral assemblage of Homo naledi found in the Dinaledi Chamber provides a unique opportunity to test hypotheses regarding the taxonomy, locomotion, and loading patterns of this species. Here we describe neck and shaft cross-sectional structure of all the femoral fossils recovered in the Dinaledi Chamber and compare them to a broad sample of fossil hominins, recent humans, and extant apes. Cross-sectional geometric (CSG) properties from the femoral neck (base of neck and midneck) and diaphysis (subtrochanteric region and midshaft) were obtained through CT scans for H. naledi and through CT scans or from the literature for the comparative sample. The comparison of CSG properties of H. naledi and the comparative samples shows that H. naledi femoral neck is quite derived with low superoinferior cortical thickness ratio and high relative cortical area. The neck appears superoinferiorly elongated because of two bony pilasters on its superior surface. Homo naledi femoral shaft shows a relatively thick cortex compared to the other hominins. The subtrochanteric region of the diaphysis is mediolaterally elongated resembling early hominins while the midshaft is anteroposteriorly elongated, indicating high mobility levels. In term of diaphyseal robusticity, the H. naledi femur is more gracile that other hominins and most apes. Homo naledi shows a unique combination of characteristics in its femur that undoubtedly indicate a species committed to terrestrial bipedalism but with a unique loading pattern of the femur possibly consequence of the unique postcranial anatomy of the species., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Limb bone articular and diaphyseal proportions have been shown to relate to locomotor behavior in broad comparisons across catarrhines, but comparisons among phylogenetically and functionally more closely related species may be particularly useful in investigating form-function relationships that can be applied to fossil taxa. Here we compare inter- and intra-limb proportions of diaphyseal strength and articular surface area and breadth of the femur and humerus with frequencies of leaping and vertical climbing behavior in 13 cercopithecid species. Leaping frequency is highly positively correlated with femoral/humeral diaphyseal strength, moderately positively correlated with femoral/humeral articular breadth, and less highly correlated with femoral/humeral articular surface area. These results are consistent with predicted higher bending loads as well as joint reaction forces on the femora of leapers. Surface areas may show a weaker association because they also directly impact joint excursion and are thus more influenced by other aspects of locomotion, including climbing. Climbing frequency is positively correlated with humeral head articular surface area/diaphyseal strength, but weakly negatively correlated with femoral head articular surface area/diaphyseal strength. These combined trends lead to a strong negative association between climbing and femoral/humeral head surface area. Femoral/humeral diaphyseal strength and distal articular breadth are not correlated with climbing frequency. The climbing results are consistent with greater shoulder mobility in more frequent vertical climbers. The lack of such a relationship in the femur among these taxa contrasts with earlier findings for catarrhines more generally, including hominoids, and may be a result of different climbing kinematics in cercopithecoids involving less hip abduction than in hominoids. Different use of the forelimb during climbing in cercopithecoids and hominoids may also explain the lack of association between femoral/humeral diaphyseal strength and climbing in the present study, in contrast to comparisons across catarrhines more generally., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Indentation hardness test is a good in vitro method of bone quality assessment. The purpose of this study is to explore the distribution characteristics of bone tissue microhardness in tibial diaphysis and provide theoretical support for the test site selection of the reference point indentation technique.Three fresh right tibias were obtained from 3 cadaver donors. The tibial diaphysis was evenly divided into 6 sections. Bone specimens with a thickness of 3 mm were cut from each part. After appropriate management, micro-indentation tests were performed in various regions of the specimens to acquire the microhardness values of the tibial diaphysis. Statistical analysis was performed by randomized block design variance analysis to study the distribution characteristics of bone microhardness.72 regions were selected for 360 effective indentations. We found that the bone microhardness is inhomogeneous in tibia diaphysis. Mean hardness value of the anterior, medial, posterior, lateral region of tibia diaphysis was 45.58 ± 4.39 Vickers hardness (HV), 52.33 ± 3.93 HV, 54.00 ± 4.21 HV, 52.89 ± 4.44 HV, respectively. The anterior cortex exhibits lower microhardness value than the other regions (P < .001). Within the same region, microhardness varies significantly with positions in the tibial diaphysis. The variations in indentation hardness are bound to have a significant impact on the comparability of different reference point indentation (RPI) studies.The results of this study indicated the regional microhardness difference in the human tibia diaphysis. The microhardness of different planes in the same region is also inconsistent. Inhomogeneous distribution of indentation microhardness would have considerable influence in the test site selection of RPI technique. The data collected in our study would contribute to the design of highly precise 3D printing implants and bionic bones with gradient elastic modulus.

Objectives: The aim of this study was to investigate activity-induced effects from bone geometric properties of the proximal femur in athletic vs nonathletic healthy females by statistically controlling for variation in body size, lower limb isometric, and dynamic muscle strength, and cross-sectional area of Musculus gluteus maximus., Methods: The material consists of hip and proximal thigh magnetic resonance images of Finnish female athletes (N = 91) engaged in either high jump, triple jump, soccer, squash, powerlifting, endurance running or swimming, and a group of physically active nonathletic women (N = 20). Cross-sectional bone geometric properties were calculated for the lesser trochanter, sub-trochanter, and mid-shaft of the femur regions. Bone geometric properties were analyzed using a general linear model that included body size, muscle size, and muscle strength as covariates., Results: Body size and isometric muscle strength were positively associated with bone geometric properties at all three cross-sectional levels of the femur, while muscle size was positively associated with bone properties only at the femur mid-shaft. When athletes were compared to nonathletic females, triple jump, soccer, and squash resulted in greater values in all studied cross-sections; high jump and endurance running resulted in greater values at the femoral mid-shaft cross-section; and swimming resulted in lower values at sub-trochanter and femur mid-shaft cross-sections., Conclusions: Activity effects from ground impact loading were associated with higher bone geometric values, especially at the femur mid-shaft, but also at lesser and sub-trochanter cross-sections. Bone geometric properties along the femur can be used to assess the mechanical stimuli experienced, where ground impact loading seems to be more important than muscle loading., (© 2019 Wiley Periodicals, Inc.)

The cross-sectional geometry (CSG) of long bone diaphyses is used in bioanthropology to evaluate their resistance to biomechanical constraints and to infer life-history-related patterns such as mobility, activity specialization or intensity, sexual dimorphism, body mass and proportions. First limited by technical analytical constraints to the analysis of one or two cross sections per bone, it has evolved into the analysis of cross sections of the full length of the diaphyseal part of long bones. More recently, researchers have developed analytical tools to map the cortical thickness of entire diaphyses to evaluate locomotor signatures. However, none of these analytical tools are easy to use for scientists who are not familiar with computer programming, and some statistical procedures-such as mapping the correlation coefficients of the diaphyseal thickness with various parameters have yet to be made available. Therefore, we developed an automated and open-source application that renders those analyses (both CSG and cortical thickness) in a semiautomated and user friendly manner. This application, called "Diaphysator", is associated with another free software ("Extractor", presented in Dupej et al. (2017). American Journal of Physical Anthropology, 164, 868-876). Diaphysator can be used as an online application (https://diaphysator.shinyapps.io/maps) or as a package for R statistical software. Along with the mean maps of cortical thickness and mean CSG parameter graphs, the users can evaluate the correlations and partial correlations of both CSG parameters at every cross section along the diaphyseal length, and cortical thickness data points of the entire diaphysis, with any factor such as age, sex, stature, and body mass., (© 2019 Wiley Periodicals, Inc.)

The diaphyseal cross-sectional geometric properties of the humerus, femur and tibia have been extensively used for studying their adaptation to mechanical loading. To date common practices for such studies involve either computed tomography or the latex cast method in conjunction with image analysis for calculating such properties. With the advent of modern laser scanning and photogrammetry technologies in biological anthropology, the computation of the cross-sectional geometric properties directly from 3D models is a viable and sensible alternative. Nevertheless, such method has not been properly implemented as yet. A dedicated toolkit, named long-bone-diaphyseal-CSG-Toolkit, comprising a set of functions for the GNU Octave programming language, is presented here. Offering a robust analytical implementation and an easy to follow application either for a single bone or in batch-processing mode, the toolkit requires minimum user intervention and also provides functionality for graphical representation of the calculated periosteal contours and their respective cross-sectional geometric properties. Finally, the long-bone-diaphyseal-CSG-Toolkit utilizes advanced optimization algorithms, which eliminate intra- and inter-observer error by reliably orienting the cross-sectional contours to a well-defined orientation and close to the bone's true anatomical position, which provides a significant advantage over the latex cast method., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Objective: To investigate the bone hardness of different anatomical regions of the human radius and its impact on the pullout strength of screws., Methods: Fresh radius bones were obtained from three donated cadavers. They were divided into three parts: proximal metaphysis, shaft, and distal metaphysis. The proximal metaphysis contains the head, neck, and radial tuberosity. The distal metaphysis includes the palmaris radius and the styloid process. The shaft of the radius was divided into nine segments of equal length. The bone hardness of three radiuses, one from each cadaver, was measured by Vickers microindentation hardness tests, and the screw pullout strength was examined in the other three radiuses using a materials testing machine. The trend between radius hardness and pullout strength was analyzed by using an analysis of variance randomized block design. Pearson correlation analysis was performed to evaluate the linear correlation between the bone hardness and the pullout strength of the human radius., Results: The mean hardness ranged from 33.30 HV (the head) to 43.82 HV (the diaphysis). The hardest part of the radius was the shaft, with a value of 42.54 ± 5.59 HV. The proximal metaphysis had a hardness value of 34.15 ± 6.48 HV, and the distal metaphysis hardness value was 35.24 ± 5.17 HV. The shaft was 23.5% harder than the proximal metaphysis and 20% harder than the distal metaphysis. The microhardness test demonstrated that the bone hardness value of the diaphysis was significantly higher than those of both the proximal and distal metaphysis of the radius (both P < 0.05). The mean pullout strength values ranged from 552 N (the distal metaphysis) to 2296 N (the diaphysis). The greatest pullout strength of the radius was observed for the shaft, with a pullout strength of 1727.96 ± 111.44 N. The pullout strength of the proximal metaphysis was 726.33 ± 236.39 N, and the pullout strength of the distal metaphysis was 590.67 ± 36.30 N. The pullout strength of the shaft was 138% greater than that of the proximal metaphysis and 190% greater than that of the distal metaphysis. The pullout strength was also higher in the diaphysis than at both ends of the radius (both P < 0.05). A positive correlation was found between bone hardness and pullout strength (R = 0.927, P < 0.001)., Conclusions: Bone hardness and screw pullout strength are higher in the diaphysis of the radius than at either end. The pullout strength is positively related to bone hardness in the human radius., (© 2019 The Authors. Orthopaedic Surgery published by Chinese Orthopaedic Association and John Wiley & Sons Australia, Ltd.)

Osteons are the primary sites of cortical bone lesions. However, many aspects of osteon microstructure remain poorly understood. This study aimed to explores interindividual differences in the osteon morphotype distributions in the human femoral diaphysis by evaluating the secondary osteon distributions in samples from human femurs. Two anonymized bone fragments from two modern Japanese femurs were examined. Twelve continuous transverse femoral diaphysis specimens were prepared from each fragment. Imaging examinations were conducted using a circularly polarized light microscope, and cross-sectional images were rendered using graphical synthesis software. Osteons in the images were identified as either bright-type osteons, dark-type osteons, or an others type. The two femurs were compared, and the secondary osteon morphotype distributions in different regions of their cross-sections were analyzed. When the two femurs were compared, significant differences in osteon density were observed in some regions and cross-sections. The dark-type osteon presence was strongest in the anterior and posterior regions of the femurs. The analytical method used in this study was found to be able to evaluate osteon microstructure. The results suggest that examining additional specimens and analyzing the biomechanical underpinnings of interindividual differences in osteon distribution patterns may help to improve our understanding of osteon microstructure.

A ∼1.52 Ma adult upper limb skeleton of Paranthropus boisei (KNM-ER 47000) recovered from the Koobi Fora Formation, Kenya (FwJj14E, Area 1A) includes most of the distal half of a right humerus (designated KNM-ER 47000B). Natural transverse fractures through the diaphysis of KNM-ER 470000B provide unobstructed views of cortical bone at two sections typically used for analyzing cross-sectional properties of hominids (i.e., 35% and 50% of humerus length from the distal end). Here we assess cross-sectional properties of KNM-ER 47000B and two other P. boisei humeri (OH 80-10, KNM-ER 739). Cross-sectional properties for P. boisei associated with bending/torsional strength (section moduli) and relative cortical thickness (%CA; percent cortical area) are compared to those reported for nonhuman hominids, AL 288-1 (Australopithecus afarensis), and multiple species of fossil and modern Homo. Polar section moduli (Z p ) are assessed relative to a mechanically relevant measure of body size (i.e., the product of mass [M] and humerus length [HL]). At both diaphyseal sections, P. boisei exhibits %CA that is high among extant hominids (both human and nonhuman) and similar to that observed among specimens of Pleistocene Homo. High values for Z p relative to size (M × HL) indicate that P. boisei had humeral bending strength greater than that of modern humans and Neanderthals and similar to that of great apes, A. afarensis, and Homo habilis. Such high humeral strength is consistent with other skeletal features of P. boisei (reviewed here) that suggest routine use of powerful upper limbs for arboreal climbing., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Objectives: Daily activities involve biomechanical strains acting on skeletal structures. This study identifies differences in activity patterns between males and females, and between young, middle, and older aged individuals within an excavated Muisca skeletal sample from the Eastern Andes region of Northern South America., Materials and Methods: The Tibanica archaeological site (AD 1000-1400) is located at 2600 masl on the Sabana de Bogotá, Colombia. Cross-sectional geometric analysis of femurs from 63 individuals and paired-humerii from 33 individuals was used to examine bone size (TA), strength (J) and diaphyseal shape (I max /I min , I x /I y )., Results: The findings indicate both age- and sex-related differences in activity patterns. An emphasis on upper body strength and robusticity was observed in the females, while males performed more strenuous work using their lower bodies, suggesting gender-based differences in labor. Men showed significant asymmetry in their humerii, with most showing right-hand dominance for upper body activities, while females showed high levels of humeral symmetry indicating similar levels of biomechanical stress for both arms. Female femoral diaphyseal shape changes with age, suggesting more mobility in youth and decreased mobility in middle and older ages., Discussion: These results suggest that daily life may have been structured through patterns of routine labor that united and divided particular age and sex groups. Cross-sectional geometry data indicate women likely spent significant time and energy preparing food, especially grinding maize or other foods, while men may have done more long-distance walking potentially to work in agricultural fields or procure other resources., (© 2018 Wiley Periodicals, Inc.)

Objectives: A number of studies have demonstrated the ontogenetic plasticity of long bone diaphyseal structure in response to mechanical loading. Captivity should affect mechanical loading of the limbs, but whether captive apes grow differently than wild apes has been debated. Here, we compare captive and wild juvenile and adult Gorilla to ascertain whether growth trajectories in cross-sectional diaphyseal shape are similar in the two environments., Materials and Methods: A sample of young juvenile (n = 4) and adult (n = 10) captive Gorilla gorilla gorilla specimens, with known life histories, were compared with age-matched wild G.g. gorilla (n = 62) and G. beringei beringei (n = 75) in relative anteroposterior to mediolateral bending strength of the femur, tibia, and humerus. Cross sections were obtained using peripheral quantitative CT., Results: Captive and wild adult G.g. gorilla differed in bending strength ratios for all three bones, but these differences were not present in young juvenile G.g. gorilla. In comparisons across taxa, captive juvenile G.g. gorilla were more similar to wild G.g. gorilla than to G.b. beringei, while captive adult G.g. gorilla were more similar in shape to G.b. beringei in the hind limb., Discussion: Captive and wild G. gorilla follow different ontogenetic trajectories in long bone diaphyseal shape, corresponding to environmental differences and subsequent modified locomotor behaviors. Differences related to phylogeny are most evident early in development., (© 2018 Wiley Periodicals, Inc.)

Purpose: The indication for operative treatment of displaced midshaft clavicle fractures remains controversial. However, if plate fixation is considered, implant prominence and skin irritation are the most common causes for re-operation. Low profile implants as well as closely contouring plates to the individual anatomy may reduce these complications. The aim of this study was to compare the fitting accuracy and implant prominence of 3.5mm pelvic reconstruction plates (PRP) with pre-contoured anatomical clavicle plates (PACP) for midshaft clavicle fractures., Methods: Three-dimensional data of the largest, median and smallest male and female clavicle of an existing database of 89 cadaveric clavicles were included for analysis. A three-dimensional model of a commercially available PACP was used for digitally positioning of the plate on the segmented clavicles. Three-dimensional printouts of each clavicle were produced and the 3.5mm reconstruction plates were manually bent and positioned by the senior author. Computed tomography scans and three-dimensional reconstructions were then obtained to digitally compare the fitting accuracy and implant prominence., Results: Pelvic reconstruction plates offered superior fitting accuracy and lower implant prominence compared to PACP. The largest difference in implant prominence was observed in large sized female clavicles and measured 3.6mm., Conclusion: Both, the less costly PRP plates and commercially available PACP for midshaft fractures of the clavicle demonstrated a clinically acceptable fitting accuracy. The manually bent pelvic-reconstruction plates demonstrated reduced implant prominence with superior fitting. Hypothetically this might contribute to a reduced rate of reoperation., Level of Evidence: Level IV cadaveric study., (Copyright © 2018 Elsevier Masson SAS. All rights reserved.)

Objectives: The effects of phylogeny and locomotor behavior on long bone structural proportions are assessed through comparisons between adult and ontogenetic samples of extant gorillas., Materials and Methods: A total of 281 wild-collected individuals were included in the study, divided into four groups that vary taxonomically and ecologically: western lowland gorillas (G. g. gorilla), lowland and highland grauer gorillas (G. b. graueri), and Virunga mountain gorillas (G. b. beringei). Lengths and articular breadths of the major long bones (except the fibula) were measured, and diaphyseal cross-sectional geometric properties determined using computed tomography. Ages of immature specimens (n = 145) were known or estimated from dental development. Differences between groups in hind limb to forelimb proportions were assessed in both adults and during development., Results: Diaphyseal strength proportions among adults vary in parallel with behavioral/ecological differences, and not phylogeny. The more arboreal western lowland and lowland grauer gorillas have relatively stronger forelimbs than the more terrestrial Virunga mountain gorillas, while the behaviorally intermediate highland grauer gorillas have intermediate proportions. Diaphyseal strength proportions are similar in young infants but diverge after 2 years of age in western lowland and mountain gorillas, at the same time that changes in locomotor behavior occur. There are no differences between groups in length or articular proportions among either adults or immature individuals., Conclusion: Long bone diaphyseal strength proportions in gorillas are developmentally plastic, reflecting behavior, while length and articular proportions are much more genetically canalized. These findings have implications for interpreting morphological variation among fossil taxa., (© 2018 Wiley Periodicals, Inc.)

Long bone inner structure and cross-sectional geometry display a strong functional signal, leading to convergences, and are widely analyzed in comparative anatomy at small and large taxonomic scales. Long bone microanatomical studies have essentially been conducted on transverse sections but also on a few longitudinal ones. Recent studies highlighted the interest in analyzing variations of the inner structure along the diaphysis using a qualitative as well as a quantitative approach. With the development of microtomography, it has become possible to study three-dimensional (3D) bone microanatomy and, in more detail, the form-function relationships of these features. This study focused on the selection of quantitative parameters to describe in detail the cross-sectional shape changes and distribution of the osseous tissue along the diaphysis. Two-dimensional (2D) virtual transverse sections were also performed in the two usual reference planes and results were compared with those obtained based on the whole diaphysis analysis. The sample consisted in 14 humeri and 14 femora of various mammalian taxa that are essentially terrestrial. Comparative quantitative analyses between different datasets made it possible to highlight the parameters that are strongly impacted by size and phylogeny and the redundant ones, and thus to estimate their relevance for use in form-function analyses. The analysis illustrated that results based on 2D transverse sections are similar for both sectional planes; thus if a strong bias exists when mixing sections from the two reference planes in the same analysis, it would not problematic to use either one plane or the other in comparative studies. However, this may no longer hold for taxa showing a much stronger variation in bone microstructure along the diaphysis. Finally, the analysis demonstrated the significant contribution of the parameters describing variations along the diaphysis, and thus the interest in performing 3D analyses; this should be even more fruitful for heterogeneous diaphyses. In addition, covariation analyses showed that there is a strong interest in removing the size effect to access the differences in the microstructure of the humerus and femur. This methodological study provides a reference for future quantitative analyses on long bone inner structure and should make it possible, through a detailed knowledge of each descriptive parameter, to better interpret results from the multivariate analyses associated with these studies. This will have direct implications for studies in vertebrate anatomy, but also in paleontology and anthropology., (© 2018 Anatomical Society.)

Objectives: Analyses of bone cross-sectional geometry are frequently used by anthropologists and paleontologists to infer the loading histories of past populations. To address some underlying assumptions, we investigated the relative roles of genetics and exercise on bone cross-sectional geometry and bending mechanics in three mouse strains: high bone density (C3H/He), low bone density (C57BL/6), and a high-runner strain homozygous for the Myh4 Minimsc allele (MM)., Methods and Materials: Weanlings of each strain were divided into exercise (wheel) or control (sedentary) treatment groups for a 7-week experimental period. Morphometrics of the femoral mid-diaphysis and mechanical testing were used to assess both theoretical and ex vivo bending mechanics., Results: Across all measured morphological and bending traits, we found relatively small effects of exercise treatment compared to larger and more frequent interstrain differences. In the exercised group, total distance run over the experimental period was not a predictor of any morphological or bending traits. Cross-sectional geometry did not accurately predict bone response to loading., Discussion: Results from this experimental model do not support hypothesized associations among extreme exercise, cross-sectional geometry, and bending mechanics. Our results suggest that analysis of cross-sectional geometry alone is insufficient to predict loading response, and questions the common assumption that cross-sectional geometry differences are indicative of differential loading history., (© 2017 Wiley Periodicals, Inc.)

Stature estimation is rarely attempted in sub-adults due to the general lack of available standards as a result of the dearth of sufficiently large sub-adult skeletal collections with known demographic information. To overcome this problem sub-adult research mainly relies on modern imaging modalities. In the current study Magnetic Resonance Imaging (MRI) scans were used to assess the use of the anatomical method for stature estimation in sub-adults. A total of 53 Black South African sub-adult males (n=24) and females (n=29) aged between 10 and 17 years participated in the study by voluntarily completing a full-body MRI scan. A stadiometer was used to measure living stature prior to all MRI scans. Skeletal elements that contribute directly to stature were measured from the MRI scans using OsiriX and summed to compute the total skeletal height. Total skeletal height was calculated using the diaphyseal, maximum and physiological long bone lengths and correlated to living stature using Pearson's correlations. Subsequently least squares regression equations were generated for the estimation of sub-adult stature. Results indicated strong, statistically significant positive correlations between living stature and total skeletal heights in sub-adult males, females and a combined sex sample. The regression equations were characterized by small standard error of estimates which are comparable to that reported for Black South African adults. Based on these results the anatomical method can be used to accurately describe living stature in Black South African sub-adults. This method is therefore encouraged as it will add valuable information when dealing with unknown sub-adult skeletal remains., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Inferring the morphology of the last common ancestor of humans, chimpanzees and gorillas is a matter of ongoing debate. Recent findings and reassessment of fossil hominins leads to the hypothesis that the last common ancestor was not extant African ape-like. However, an African great-ape-like ancestor with knuckle walking features still remains plausible and the most parsimonious scenario. Here we address this question via an evolutionary developmental approach, comparing taxon-specific patterns of shape change of the femoral diaphysis from birth to adulthood in great apes, humans, and macaques. While chimpanzees and gorillas exhibit similar locomotor behaviors, our data provide evidence for distinct ontogenetic trajectories, indicating independent evolutionary histories of femoral ontogeny. Our data further indicate that anthropoid primates share a basic pattern of femoral diaphyseal ontogeny that reflects shared developmental constraints. Humans escaped from these constraints via differential elongation of femur.

Radiation therapy (RTx) is associated with increased risk for late-onset fragility fractures in bone tissue underlying the radiation field. Bone tissue outside the RTx field is often selected as a "normal" comparator tissue in clinical assessment of fragility fracture risk, but the robustness of this comparison is limited by an incomplete understanding of the systemic effects of local radiotherapy. In this study, a mouse model of limited field irradiation was used to quantify longitudinal changes in local (irradiated) and systemic (non-irradiated) femurs with respect to bone density, morphology, and strength. BALB/cJ mice aged 12 weeks underwent unilateral hindlimb irradiation (4 × 5 Gy) or a sham procedure. Femurs were collected at endpoints of 4 days before treatment and at 0, 1, 2, 4, 8, 12, and 26 weeks post-treatment. Irradiated (RTx), Contralateral (non-RTx), and Sham (non-RTx) femurs were imaged by micro-computed tomography and mechanically tested in three-point bending. In both the RTx and Contralateral non-RTx groups, the longer-term (12- to 26-week) outcomes included trabecular resorption, loss of diaphyseal cortical bone, and decreased bending strength. Contralateral femurs generally followed an intermediate response compared with RTx femurs. Change also varied by anatomic compartment; post-RTx loss of trabecular bone was more profound in the metaphyseal than the epiphyseal compartment, and cortical bone thickness decreased at the mid-diaphysis but increased at the metaphysis. These data demonstrate that changes in bone quantity, density, and architecture occur both locally and systemically after limited field irradiation and vary by anatomic compartment. Furthermore, the severity and persistence of systemic bone damage after limited field irradiation suggest selection of control tissues for assessment of fracture risk or changes in bone density after radiotherapy may be challenging. © 2017 American Society for Bone and Mineral Research., (© 2017 American Society for Bone and Mineral Research.)

Purpose: The aim of this study was to evaluate the feasibility of performing minimally-invasive plate osteosynthesis (MIPO) in tibial fractures using two posteromedial incisions, and to measure the distance between the plate and neurovascular structures., Materials and Methods: We performed nine dissections of specimens that were submitted to tibial MIPO with two posteromedial incisions. One locking compression plate (LCP) of 14 to 16 holes was inserted into the submuscular tunnel in a retrograde manner. Incisions were linked to evaluate the distance between neurovascular structures and the plate., Results: During the proximal incision, a blunt dissection between semitendinosus and medial gastrocnemius tendons, as well as their lateral shift, helped to protect the main local neurovascular structures. In its distal portion, the submuscular plate tunnel insertion and its direction to the proximal incision prevented direct contact and possible damage to neurovascular structures. Moreover, we obtained successful results from a patient submitted to this procedure., Conclusion: Posteromedial MIPO represents a safe and attractive alternative for tibial fractures, particularly if there are damaged soft tissues in the anterior and medial side, or when access to intramedullary osteosynthesis is blocked., (© 2017 Elsevier Ltd. All rights reserved.)

Studies of ancient human skeletal remains frequently proceed from the assumption that individuals with robust limb bones and/or rugose, hypertrophic entheses can be inferred to have been highly physically active during life. Here, we experimentally test this assumption by measuring the effects of exercise on limb bone structure and entheseal morphology in turkeys. Growing females were either treated with a treadmill-running regimen for 10 weeks or served as controls. After the experiment, femoral cortical and trabecular bone structure were quantified with μCT in the mid-diaphysis and distal epiphysis, respectively, and entheseal morphology was quantified in the lateral epicondyle. The results indicate that elevated levels of physical activity affect limb bone structure but not entheseal morphology. Specifically, animals subjected to exercise displayed enhanced diaphyseal and trabecular bone architecture relative to controls, but no significant difference was detected between experimental groups in entheseal surface topography. These findings suggest that diaphyseal and trabecular structure are more reliable proxies than entheseal morphology for inferring ancient human physical activity levels from skeletal remains., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Intramedullary nailing of diaphyseal long bone fractures is a standard procedure in today's trauma and orthopedic surgery due to the numerous advantages (e.g. minimal invasive, limited soft tissue damage, load stability). In the last decade indications have been extended to the metaphyseal region. This was associated with problems and complications due to the reduced bone-implant interface. The changed anatomical conditions lead to decreased implant anchorage. Newly developed locking solutions overcome most of these problems. First, the number and also the orientation of the locking screws were adapted to allow a multiplanar locking. This results in increased implant anchorage in the soft metaphyseal bone, thus construct stability significantly improved. Additional options like angular stable locking have been introduced and furthermore enhanced construct stability especially in poor bone stock. As a perspective locking screw augmentation shows promising results in first biomechanical testing., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Objectives: Studies of male and female long bone growth in past populations are limited and usually constrained by the lack of personal identification. This article aimed to evaluate long bone growth in a series of mid-19 th century documented burials associated with the urban poor from Bethnal Green, London, UK., Materials and Methods: Maximum diaphyseal lengths from 74 males and 70 females (2 months to 12 years) were compared to modern reference data from North America. Diaphyseal lengths were expressed as a percentage of expected length and an average percentage value was calculated across all available long bones. An index of growth progression was introduced to explore differences in the progress of males and females towards their projected adult size., Results: Deviation from the expected growth attainment was evident in both sexes in the archaeological series by 2-4 months of age. Only 19.4% (28/144) of the children had attained an average long bone length >90% of the predicted mean in the reference series. The percentage of expected growth attainment decreased steadily in both sexes during infancy and early childhood. Overall, females deviated further from their expected growth progression than males., Discussion: Growth faltering in both males and females was established during infancy (<1 year) with no evidence for recovery in older age groups. Early weaning and inadequate artificial feeding, together with impoverished living conditions and limited sanitary provision, most likely impacted on childhood growth., (© 2017 Wiley Periodicals, Inc.)

Objectives: Many studies on subadult sex estimation focus on elements that express sexually dimorphic features in adults. In contrast, diaphyseal dimensions have been shown to display sex-specific differences prior to adolescence. The current study evaluates the use of diaphyseal dimensions in subadult sex estimation., Materials and Methods: Eighteen postcranial measurements from six long bones were collected on Lodox Statscan radiographic images of 1,310 modern South African children between birth and 12 years of age. Linear (LDA) and flexible discriminant analysis (FDA) and logistic regression were employed with single and multiple variable models with age both included and excluded from the model. Bootstrapped cross-validation was employed because some of the multiple variable subsets had small sample sizes. Each of the bootstrapped accuracies has an associated 95% confidence interval demonstrating the ranges in classification., Results: Classification methods utilizing multiple variables achieved the highest bootstrapped classification accuracies (70% to 93%). The inclusion of age in the models did not consistently increase or decrease the classification accuracies. Proximal and distal breadth measurements were consistently recognized as important measurements in model creation. FDA yielded the highest overall accuracies, but the logistic regression presented with overall smaller bootstrapped 95% confidence intervals., Discussion: Quantifiable sex differences were discovered in the appendicular skeleton of children between birth and 12 years of age. The high classification accuracies were likely due to using numerous predictor variables from multiple skeletal elements, which were optimized for classification using FDA. To facilitate application, a graphical user interface, KidStats, was developed., (© 2017 Wiley Periodicals, Inc.)

Background: The radiocapitellar line (RCL) was originally described for evaluation of the alignment of the RC joint on lateral images of the elbow. Although, many authors have translated the utilization of RCL into coronal imaging, previous studies have not been performed to confirm validity. The purpose of this paper was to identify an accurate way of evaluating pediatric RC alignment in the coronal plane., Methods: Thirty-seven anteroposterior (AP) radiographs of 37 children were evaluated to determine the position of the RC joint in the coronal plane. All had acceptable magnetic resonance imaging (MRI) studies available for comparison. The lateral humeral line (LHL), consisting of a line along the lateral edge of the ossified condyle of the distal humerus parallel to the axis of the distal humeral shaft, was studied as it related to the lateral cortex of the radial neck. Three children with a confirmed diagnosis of a Bado III, lateral displaced radius, Monteggia fracture were also evaluated., Results: The LHL passed along the edge of or lateral to the radial neck on all AP radiographs and all MRI studies. The RCL failed to intersect the capitellum on 2 AP radiographs. On MRI, the RCL also passed lateral to the capitellar ossification center in 3 patients. In addition, the RCL was seen passing through the capitellum at a mean of the lateral 30% (range, 0% to 64%) on AP radiographs and 26% (range, 0% to 48%) on MRI. For all 3 children with a Bado III Monteggia fracture, the LHL crossed the radial neck and the RCL did not intersect the capitellum., Conclusions: The RCL can fail to intersect the capitellar ossification center on AP radiographs and MRI in pediatric elbows without injury. The LHL consistently lies lateral to the radial neck in normal elbows and medial to the lateral aspect of the radial neck on all Bado III fracture-dislocations. It, therefore, can be used as an adjunct in evaluating the RC joint on AP imaging. The RCL most commonly intersects the lateral one third of the ossification center on both plain radiographs and MRIs., Level of Evidence: Level III-diagnostic.