Which measures of diaphyseal robusticity are robust? A comparison of external methods of quantifying the strength of long bone diaphyses to cross-sectional geometric properties

Shaft structure of the first metatarsal contains a strong phylogenetic signal in apes and humans

OBJECTIVES

Metatarsal bones constitute a key functional unit of the foot in primates. While the form-function relationships of metatarsals have been extensively studied, particularly in relation to the loss of the grasping ability of the foot in humans in contrast to apes, the effect of phyletic history on the metatarsal morphology and its variability remains largely unknown.

MATERIALS AND METHODS

Here, we evaluate how the strength of the phylogenetic signal varies from the first to the fifth metatarsal in humans, chimpanzees, gorillas, orangutans, gibbons, and Japanese macaques. We use computed tomography imaging and morphometric mapping to quantify the second moment of area around and along the metatarsal shaft and evaluate the strength of the phylogenetic signal with multivariate K-statistics.

RESULTS

The shaft structure of the first metatarsal, but not the others, correlates well with the phylogeny of apes and humans.

DISCUSSION

Given the importance of the first metatarsal for grasping and bipedal/quadrupedal locomotion, the strong phylogenetic but weak functional signal in its structure is unexpected. These findings suggest that the evolutionary diversification of hominoid locomotor behaviors, including human bipedality, is only partly reflected in form-function relationships of key skeletal elements, and that phylogenetic history acted as a major evolutionary constraint.

Inferring the mobility of a middle Upper Paleolithic female skeleton from Caviglione (Liguria, Italy): Impact of trauma and mountainous terrain

Mobility and territory occupation, the participation of injured individuals in group activities, and the role of women in early human groups are crucial issues in human evolution. Previously, a biomechanical study showed evidence of several traumas to the upper limb of the well-preserved middle Upper Paleolithic (UP) female skeleton from Caviglione (Caviglione 1, Liguria, Italy) but did not characterize their impact on locomotor behavior. Furthermore, mobility in the European UP context is thoroughly documented in males but not in females. Therefore, we examined whether this trauma-affected female skeleton shows bone adaptation to high mobility, as expected in UP groups, and to frequent foot eversion and inversion, as expected, given the mountainous area in which it was discovered. This study investigated the structural properties of the femur, tibia, fibula, and first metatarsal to infer the mobility level and pattern of Caviglione 1. We analyzed the diaphyseal 'shape', robusticity, fibular cortical distribution, and relative robusticity (fibula versus tibia). No substantial findings were derived from the first metatarsal. The fibular cortical distribution can discriminate 'active' (nomadic or settled) and recent sedentary human groups; these findings indicated Caviglione 1 belonged to the former. Interestingly, compared with ancient and recent sedentary humans and some UP individuals, Caviglione 1 had femurs with strong relative anteroposterior rigidity and robust tibias and fibulas reflecting an adaptation to extremely high levels of mobility. The very high relative fibular robusticity of Caviglione 1, higher than that of Middle UP males, is consistent with bone adaptation to frequent travel through mountainous terrain. Such fibular robusticity may also be a consequence of imbalance, due to upper limb traumas, when traveling downhill. These findings indicate that injured individuals may have participated in subsistence activities in past populations and describe an UP female with bone adaptations to habitual high mobility, notably in mountainous terrain.

A comparative study of robusticity indices of long bones among hunter-gatherers and early agro-pastoral groups of India

OBJECTIVES

Diaphyseal robusticity and cross-sectional shapes of the bone tissues are influenced by mechanical loading history. It changes according to work demand on the body. It is the objective of this study to identify the shifts in the modes of subsistence, activities and mobility patterns through the comparison of the shape and strength of bone diaphyses among the Mesolithic, Chalcolithic and Harappan populations of India.

MATERIALS AND METHODS

For the analysis, 7 sites including 2 from Mesolithic (8000-4000 bc), 2 from Chalcolithic (2000-700 bc) and 3 from Harappan (3500-1800 bc) contexts are considered. The ratio obtained from the maximum length of the bones to their girth (at 50% or 35% from the distal end) and that from anterior-posterior and medio-lateral diameters were calculated (following Martin and Saller codes, 1957) to understand certain functional adaptations and stress markers on preserved long bones. Independent-sample T-tests and ANOVA were applied to detect mean differences of statistical significance within and between cultures.

RESULTS

The robusticity indices obtained from the humeri increase from the hunting-gathering phase (M/F; 19.39/18.45) to the Chalcolithic phase (M/F; 21.99/19.39) showing a slight drop in the Harappan phase (M/F; 18.58/18.37). The right humeri of Mesolithic females show a directional asymmetry of length (4.08%-5.13%) while that in males reach up to 26.09% indicating right-dominant lateralization. In the Harappan phase, females show a greater value for the right ranging from 0.31% to 3.07%. The femoral robusticity of females increases from 11.42 in hunting-gathering societies to 13.28 in Harappan times while mid-shaft of the Mesolithic population clearly shows greater loading along the anterior-posterior (A-P) plane as the index in most cases exceeds 100. There are significant differences among males and females within each group in terms of the indices but significant differences could be discerned between the Mesolithic, Chalcolithic and Harappan populations in case of tibiae, radii and ulnae only.

CONCLUSION

The occupation patterns certainly changed as humans became a food-producer from a hunter-gatherer. Occupations involving the extensive flexion and extension of upper limbs in the Chalcolithic period increase particularly in the Harappan phase. Sedentism gave rise to roundness of the femur and reduced the magnitude of lateralization. While equal level of mobility can be traced in case of both the sexes before the advent of agriculture, this distinction increases between the males and females in the agro-pastoral phases.

Variation in ontogenetic trajectories of limb dimensions in humans is attributable to both climatic effects and neutral evolution

Previous studies showed that there is variation in ontogenetic trajectories of human limb dimensions and proportions. However, little is known about the evolutionary significance of this variation. This study used a global sample of modern human immature long bone measurements and a multivariate linear mixed-effects model to study 1) whether the variation in ontogenetic trajectories of limb dimensions is consistent with ecogeographic predictions and 2) the effects of different evolutionary forces on the variation in ontogenetic trajectories. We found that genetic relatedness arising from neutral (nonselective) evolution, allometric variation associated with the change in size, and directional effects from climate all contributed to the variation in ontogenetic trajectories of all major long bone dimensions in modern humans. After accounting for the effects of neutral evolution and holding other effects considered in the current study constant, extreme temperatures have weak, positive associations with diaphyseal length and breadth measurements, while mean temperature shows negative associations with diaphyseal dimensions. The association with extreme temperatures fits the expectations of ecogeographic rules, while the association with mean temperature may explain the observed among-group variation in intralimb indices. The association with climate is present throughout ontogeny, suggesting an explanation of adaptation by natural selection as the most likely cause. On the other hand, genetic relatedness among groups, as structured by neutral evolutionary factors, is an important consideration when interpreting skeletal morphology, even for nonadult individuals.

Human femur morphology and histology variation with ancestry and behaviour in an ancient sample from Vietnam

BACKGROUND

There is a genetic component to the minimum effective strain (MES)-a threshold which determines when bone will adapt to function-which suggests ancestry should play a role in bone (re)modelling. Further elucidating this is difficult in living human populations because of the high global genetic admixture. We examined femora from an anthropological skeletal assemblage (Mán Bạc, Vietnam) representing distinct ancestral groups. We tested whether femur morphological and histological markers of modelling and remodelling differed between ancestries despite their similar lifestyles.

METHODS

Static histomorphometry data collected from subperiosteal cortical bone of the femoral midshaft, and gross morphometric measures of femur robusticity, were studied in 17 individuals from the Mán Bạc collection dated to 1906-1523 cal. BC. This assemblage represents agricultural migrants with affinity to East Asian groups, who integrated with the local hunter-gatherers with affinity to Australo-Papuan groups during the mid-Holocene. Femur robusticity and histology data were compared between groups of 'Migrant' (n = 8), 'Admixed' (n = 4), and 'Local' (n = 5).

RESULTS

Local individuals had more robust femoral diaphyses with greater secondary osteon densities, and relatively large secondary osteon and Haversian canal parameters than the migrants. The Migrant group showed gracile femoral shafts with the least dense bone made up of small secondary osteons and Haversian canals. The Admixed individuals fell between the Migrant and Local categories in terms of their femoral data. However, we also found that measures of how densely bone is remodelled per unit area were in a tight range across all three ancestries.

CONCLUSIONS

Bone modelling and remodelling markers varied with ancestral histories in our sample. This suggests that there is an ancestry related predisposition to bone optimising its metabolic expenditure likely in relation to the MES. Our results stress the need to incorporate population genetic history into hierarchical bone analyses. Understanding ancestry effects on bone morphology has implications for interpreting biomechanical loading history in past and modern human populations.

Female bone physiology resilience in a past Polynesian Outlier community

Remodelling is a fundamental biological process involved in the maintenance of bone physiology and function. We know that a range of health and lifestyle factors can impact this process in living and past societies, but there is a notable gap in bone remodelling data for populations from the Pacific Islands. We conducted the first examination of femoral cortical histology in 69 individuals from ca. 440-150 BP Taumako in Solomon Islands, a remote 'Polynesian Outlier' island in Melanesia. We tested whether bone remodelling indicators differed between age groups, and biological sex validated using ancient DNA. Bone vascular canal and osteon size, vascular porosity, and localised osteon densities, corrected by femoral robusticity indices were examined. Females had statistically significantly higher vascular porosities when compared to males, but osteon densities and ratios of canal-osteon (~ 8%) did not differ between the sexes. Our results indicate that, compared to males, localised femoral bone tissue of the Taumako females did not drastically decline with age, contrary to what is often observed in modern populations. However, our results match findings in other archaeological samples-a testament to past female bone physiology resilience, also now observed in the Pacific region.

Variation in cross-sectional indicator of femoral robusticity in Homo sapiens and Neandertals

Variations in the cross-sectional properties of long bones are used to reconstruct the activity of human groups and differences in their respective habitual behaviors. Knowledge of what factors influence bone structure in Homo sapiens and Neandertals is still insufficient thus, this study investigated which biological and environmental variables influence variations in the femoral robusticity indicator of these two species. The sample consisted of 13 adult Neandertals from the Middle Paleolithic and 1959 adult individuals of H. sapiens ranging chronologically from the Upper Paleolithic to recent times. The femoral biomechanical properties were derived from the European data set, the subject literature, and new CT scans. The material was tested using a Mantel test and statistical models. In the models, the polar moment of area (J) was the dependent variable; sex, age, chronological period, type of lifestyle, percentage of the cortical area (%CA), the ratio of second moment areas of inertia about the X and Y axes (Ix/Iy), and maximum slope of the terrain were independent covariates. The Mantel tests revealed spatial autocorrelation of the femoral index in H. sapiens but not in Neandertals. A generalized additive mixed model showed that sex, %CA, Ix/Iy, chronological period, and terrain significantly influenced variation in the robusticity indicator of H. sapiens femora. A linear mixed model revealed that none of the analyzed variables correlated with the femoral robusticity indicator of Neandertals. We did not confirm that the gradual decline in the femoral robusticity indicator of H. sapiens from the Middle Paleolithic to recent times is related to the type of lifestyle; however, it may be associated with lower levels of mechanical loading during adolescence. The lack of correlation between the analysed variables and the indicator of femoral robusticity in Neandertals may suggest that they needed a different level of mechanical stimulus to produce a morphological response in the long bone than H. sapiens.

Adapting in the Arctic: Habitual activity and landscape interaction in Late Holocene hunter-gatherers from Alaska

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.

New horizons in reconstructing past human behavior: Introducing the "Tübingen University Validated Entheses-based Reconstruction of Activity" method

An accurate reconstruction of habitual activities in past populations and extinct hominin species is a paramount goal of paleoanthropological research, as it can elucidate the evolution of human behavior and the relationship between culture and biology. Variation in muscle attachment (entheseal) morphology has been considered an indicator of habitual activity, and many attempts have been made to use it for this purpose. However, its interpretation remains equivocal due to methodological shortcomings and a paucity of supportive experimental data. Through a series of studies, we have introduced a novel and precise methodology that focuses on reconstructing muscle synergies based on three-dimensional and multivariate analyses among entheses. This approach was validated using uniquely documented anthropological samples, experimental animal studies, histological observations, and geometric morphometrics. Here, we detail, synthesize, and critically discuss the findings of these studies, which overall point to the great potential of entheses in elucidating aspects of past human behavior.

Sex differences in diet and life conditions in a rural Medieval Islamic population from Spain (La Torrecilla, Granada): An isotopic and osteological approach to gender differentiation in al-Andalus

OBJECTIVES

Gender differentiation can influence the diet, physical activity, and health of human populations. Multifaceted approaches are therefore necessary when exploring the biological consequences of gender-related social norms in the past. Here, we explore the links between diet, physiological stress, physical activity, and gender differentiation in the Medieval Islamic population of La Torrecilla (Granada, Spain, 13th-15th century AD), by analyzing stable isotope patterns, stature, and long bone diaphyseal measurements.

MATERIALS AND METHODS

The sample includes 96 individuals (48 females, 48 males) classified as young and middle adults (20-34 and 35-50 years of age respectively). Diet was reconstructed through the analysis of δ¹³ C and δ¹⁵ N. Stature, humeral and femoral diaphyseal shape and product of diaphyseal diameters served as proxies of physiological stress and physical activity.

RESULTS

Isotopic ratios suggest a substantial dietary contribution of C₄ plants (e.g., sorghum, millet), a variable access to animal proteins, and no differences between the sexes. Sexual dimorphism in stature derives from a markedly low female stature. Long bone diaphyseal properties suggest that men performed various physically stressful activities, whereas women were involved in less physically demanding activities (possibly related to household work).

DISCUSSION

Gender differentiation in La Torrecilla was expressed by a possibly differential parental investment in male versus female offspring and by culturally sanctioned gender differences in the performance of physical tasks. Diet was qualitatively homogenous between the sexes, although we cannot rule out quantitative differences. Our results shed new light on the effects of gender-related social norms on human development and lifestyle.

Does the osteon morphology depend on the body mass? A scaling study on macroscopic and histomorphometric differences between cow (Bos taurus) and sheep (Ovis aries)

The structure and geometry of bone depend on many biological and environmental factors. These factors affect the bone tissue's microstructure differently, and their interaction has not yet been fully elucidated. Our research investigated the effect of body mass on the macro- and microstructure of the compact bone. Therefore we analyzed the humerus and femur bones from females of 11 cows and 11 sheep at the age of 4–10 years. Both species have very similar dietary and locomotion patterns, but their body size and weight are very different. Within macroscopical analyzes of bones were observed ascending order of robustness index and bone diaphysis index. In both animals, plexiform and irregular Haversian bone tissues were identified in humerus and femur. Conversely, the dense Haversian tissue present only in cow above all in the femur. The most considerable interspecific osteonal difference between sheep and cow was in the osteon density, whose average value is 37% higher in the cow. The osteons of sheep humerus are almost circular, and osteons of cow femur are more elliptical. Within both species, the femoral osteons are elliptical than those of humerus. Despite the cow weighing more than 10 times the sheep, the measurements of osteons and Haversian canals, are very similar (the values of the ratio cow/sheep for these types are comprised from 1.04 to 1.86). Our findings indicate that the body mass does not affect the size of bone microstructure, probably more sensitive to other factors as a lifestyle and locomotor ability.

Small body size phenotypes among Middle and Later Stone Age Southern Africans

Modern humans originated between 300 and 200 ka in structured populations throughout Africa, characterized by regional interaction and diversity. Acknowledgment of this complex Pleistocene population structure raises new questions about the emergence of phenotypic diversity. Holocene Southern African Later Stone Age (LSA) skeletons and descendant Khoe-San peoples have small adult body sizes that may reflect long-term adaptation to the Cape environment. Pleistocene Southern African adult body sizes are not well characterized, but some postcranial elements are available. The most numerous Pleistocene postcranial skeletal remains come from Klasies River Mouth on the Southern Cape coast of South Africa. We compare the morphology of these skeletal elements with globally sampled Holocene groups encompassing diverse adult body sizes and shapes (n = 287) to investigate whether there is evidence for phenotypic patterning. The adult Klasies River Mouth bones include most of a lumbar vertebra, and portions of a left clavicle, left proximal radius, right proximal ulna, and left first metatarsal. Linear dimensions, shape characteristics, and cross-sectional geometric properties of the Klasies River Mouth elements were compared using univariate and multivariate methods. Between-group principal component analyses group Klasies River Mouth elements, except the proximal ulna, with LSA Southern Africans. The similarity is driven by size. Klasies River Mouth metatarsal cross-sectional geometric properties indicate similar torsional and compressive strength to those from LSA Southern Africans. Phenotypic expressions of small-bodied adult morphology in Marine Isotope Stages 5 and 1 suggest this phenotype may represent local convergent adaptation to life in the Cape.

The upper limb skeleton and behavioral lateralization of modern humans from Zhaoguo Cave, southwestern China

OBJECTIVES

Aims of the study are to initially describe and comparatively evaluate the morphology of the new Zhaoguo M1 upper limb remains, and contextualize upper limb functional adaptations among those of other worldwide Upper Paleolithic (UP) humans to make inferences about subsistence-related activity patterns in southwestern China at the Pleistocene-Holocene boundary.

MATERIALS AND METHODS

The preserved Zhaoguo M1 skeletal remains include paired humeri, ulnae, and radii, among others. These specimens were scanned using micro-computed tomography to evaluate internal structural properties, while external osteometric dimensions of the Zhaoguo M1 upper limb elements also were acquired. Both sets of measurements were compared to published data on Neandertals, and Middle and Upper Paleolithic modern humans.

RESULTS

The upper limb elements of Zhaoguo M1 display a suite of characteristics that generally resemble those of other contemporary Late UP (LUP) modern humans, while robusticity indices generally fall within the upper range of LUP variation. The Zhaoguo M1 upper limb elements display fewer traits resembling those of late archaic humans. The Zhaoguo M1 individual exhibits diaphyseal asymmetry in several upper limb elements suggesting left hand dominance. When evaluating the full range of magnitudes of humeral bilateral asymmetry in the comparative sample, Zhaoguo M1 falls at the lower end overall, but yet is relatively higher than contemporary LUP modern humans specifically from East Eurasia.

DISCUSSION

The Zhaoguo M1 individual suggests typical LUP modern human upper limb morphology persisted in southwest China until the end of the last glacial period. Upper limb bone asymmetry of Zhaoguo M1 also indicates that behavioral activities attributed to a hunter-gatherer tradition apparently extended through the Pleistocene-Holocene transition in this region.

Dorso-palmar elongation of the diaphysis of the third metacarpal bone in prehistoric Jomon people

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.

Gendered division of labor in a Celtic community? A comparison of sex differences in entheseal changes and long bone shape and robusticity in the pre-Roman population of Verona (Italy, third-first century BC)

OBJECTIVES

The presence of a gendered subdivision of labor has been bioarchaeologically investigated in various prehistoric and historical contexts. Little is known, however, about the type of differences in daily activities characterizing men and women among the Celtic communities of Italy. The focus of the present study is the analysis of differences in patterns of entheseal changes (ECs) and long bone shape and robusticity between sexes among the Cenomani Gauls of Seminario Vescovile (SV-Verona, Italy, third-first century BC).

MATERIALS AND METHODS

The sample includes 56 adult individuals (22 females and 34 males). Presence of ECs on nine bilateral postcranial attachment sites, and values of humeral and femoral shape and robusticity indices based on external measurements were compared between sexes by means of generalized linear models and Mann-Whitney tests.

RESULTS

Results show a lack of difference between sexes in long bone shape and robusticity, and a higher incidence of upper and, especially, lower limb ECs in males.

DISCUSSION

These results suggest the presence of sex-specific activities at SV mostly related to farming and differently influencing the considered variables. Also, this study suggests the relevance of a series of nonbiomechanical factors (developmental, hormonal, genetic, and methodological) when attempting biocultural reconstructions from osteoarchaeological samples.

Muscle force interacts with stature to influence functionally related polar second moments of area in the lower limb among adult women

Objectives

We sought to determine the relationships between muscle size, function, and polar second moments of area (J) at the midshaft femur, proximal tibia, and midshaft tibia.

Materials and Methods

We used peripheral quantitative computed tomography to quantify right femoral and tibial J and soft tissue cross‐sectional areas, and force plate mechanography to quantify peak power output and maximum force of the right limb, among athletic women and control subjects.

Results

Lower limb bone J exhibited strong relationships with estimated force but not power between both groups. Among controls, the strongest relationships between force and J were found at the midshaft femur. Among athletes, these relationships shifted to the tibia, regardless of body size, likely reflecting functional strain related to the major knee extensors and ankle plantarflexors. Together, muscle force and stature explained as much as 82 and 48% of the variance in lower limb bone J among controls and athletes, respectively.

Discussion

Results highlight the importance of considering relevant muscle function variables (e.g., force and lever arm lengths) when interpreting behavioral signatures from skeletal remains. Future work to improve the estimation of muscle force from skeletal remains, and incorporate it with lever arm length into analyses, is warranted. Results also suggest that, in doing so, functional relationships between a given section location and musculature should be considered.

Ontogenetic changes in femoral cross-sectional geometry during childhood locomotor development

OBJECTIVES

The femur is a major weight-bearing bone that is variably loaded throughout growth as children transition through locomotory states prior to the attainment of a mature bipedal gait. Here, we document ontogenetic trends in femoral cross-sectional geometry (CSG) and explore how changes in loading regime may impact the structural arrangement of cortical bone along the length of the developing diaphysis.

MATERIALS AND METHODS

Micro-CT scans of 110 immature femora were generated from a documented archaeological sample ranging in age from birth to 8.5 years old. CSG properties indicative of relative bone strength and bending rigidity were analyzed from cross-sections extracted at 35%, 50% and 65% of total intermetaphyseal length.

RESULTS

Infants experience a marked redistribution of cortical bone between birth and 7 months facilitating a more advantageous mechanical structure for early load bearing behaviors as bone is displaced further from the section centroid. Early walkers are characterized by a mediolaterally reinforced cross-section that becomes more circular as gait continues to develop.

DISCUSSION

During ontogeny the femur undergoes distinct morphological phases, which correspond with changes in loading regime. This study illustrates the importance of loading conditions in shaping immature bone morphology. Nonmechanical factors such as changes in hormonal environmental can also impact on this dynamic.

Are entheseal changes and cross-sectional properties associated with the shape of the upper limb?

OBJECTIVES

Reconstruction of the activity of past human populations can be carried out using various skeletal markers; however, the relationship between these methods is not fully understood. Therefore, the main aim of this article is to analyze the relationship between entheseal changes, cross-sectional properties, and variability in the shape of the upper limb.

MATERIALS AND METHODS

The analyzed material consisted of CT images of 71 right scapulae, humeri, and ulnae belonging to the same individuals from a mediaeval population located in Poland. For each series of bones for the same individual, skeletal markers such as: cross-sectional properties, entheses and shape variation were assessed. Next, correlations between these three skeletal indicators were calculated.

RESULTS

In general, the models showed that only sex influences entheses. Multivariate regression revealed significant correlation only between ulnar auricular surface shape and two types of mean score for entheses.

DISCUSSION

The findings are inconsistent and stand in contradiction to other research; therefore, we suggest that an assessment of individual activity should be carried out, using as many post-cranial elements as possible and a variety of methods. This approach will ensure more accurate reconstruction of the activity levels and patterns of archeological groups.

A first comparison of bone histomorphometry in extant domestic horses (Equus caballus) and a Pleistocene Indian wild horse (Equus namadicus)

The microstructural features of the tissue of long bones subjected to different biomechanical stresses could be a helpful tool for a better understanding of locomotor behavior in extant and extinct mammals, including equids. However, few researches have attempted to describe the bone tissue of extinct horses. In our study, we analyze and compare the histomorphometric features of the bone tissue in extant modern horses, Equus caballus, and Equus namadicus, a Pleistocene Indian extinct wild horse. The number, position, and size of the osteons and Haversian canals of the bone tissue, classifiable as dense Haversian tissue, were considered for the comparison. The results obtained highlight some differences between the analyzed species, E. caballus having fewer and bigger osteons than E. namadicus. The microstructural differences may depend on the different lifestyles and environmental conditions characterizing the two species. The results obtained suggest that comparing the biomechanical properties of extinct and modern horse species may provide indirect information on their paleoenvironment.

New Insights into Activity-Related Functional Bone Adaptations and Alterations in Neolithic Liguria (Northwestern Italy)

This study offers a combined analysis of longbone mechanical properties (cross-sectional geometry, CSG), upper-limb enthesopathies (entheseal changes, ECs), and external auditory exostoses (EAEs) among Neolithic people from Liguria (Italy). Previous CSG studies have suggested a high degree of mobility in mountainous terrain and sexual dimorphism in the upper limbs, with males being more oriented toward unimanual activities and females performing strenuous bimanual tasks. The aims of the study were to: 1) increase the sample size of the CSG analysis via the acquisition of surface 3D models, 2) provide a solid chronological framework through direct dating in order to allow for subsampling of individuals dated to the Impresso-Cardial Complex (ICC, c. 5800–5000 BCE) and the Square-Mouthed Pottery culture (c. 5000–4300 BCE), 3) integrate the results of CSG analysis with information on ECs of the humeral epicondyles, and 4) assess possible marine activities through analysis of EAEs. Results from the CSG analysis confirmed those of previous studies, with no significant diachronic change. ECs in the humeral medial epicondyle parallelled CSG adaptations: males tended to display more changes, especially unilaterally. Only one individual from the ICC period showed bilateral EAE, suggesting that marine activities were not prevalent. This study adds to our knowledge on activity patterns in the Neolithic in Liguria, and shows that integrating structural adaptations with information from specific entheseal alterations and exostoses can improve reconstructions of past habitual activities.

Osteoarthritis, entheses, and long bone cross-sectional geometry in the Andes: Usage, history, and future directions

Akin to approaches encouraged by Verano (1997) in the Andes, and Ortner (2011, 2012) for general paleopathological studies, this article focuses on accurate descriptions and definitions of osteoarthritis, entheses, and long bone cross-sectional geometry. By evaluating these conditions as part of biological responses to abnormal skeletal changes and biomechanical stress, this research discusses each condition's pathogenesis. Further, this article emphasizes a "small data" approach to evaluating these conditions in ancient culturally and biologically related human populations, where the study samples must have good skeletal preservation, where estimates of age and sex need to be included as major factors, and where abnormalities need to be described and evaluated. This article also discusses global clinical and osteological research on ways scholars are currently trying to establish industry-wide methods to evaluate osteoarthritis, entheses, and long bone cross-sectional geometry. Recent studies have focused on rigorous evaluation of methodological techniques, recording protocols, and inter- and intra-observer error problems. Additionally, scholars have focused on physical intensity of movement using biomechanics, evaluated burials of known occupation, and used complex statistical methods to help interpret skeletal changes associated with these conditions. This article also narrows to focus on these conditions within thematic "small data" areas throughout the Andes. This research concludes with describing future directions to understand skeletal changes, such as more multidisciplinary studies between osteologists and pathologists, collaborations with living people to collect CT, x-rays, or computer-aided motion capture, and a stronger focus on how these conditions correlate with intense biomechanical changes in younger individuals.

Variation and Correlations in Departures from Symmetry of Brain Torque, Humeral Morphology and Handedness in an Archaeological Sample of Homo sapiens

The anatomical asymmetries of the human brain are the subject of a great deal of scientific interest because of their links with handedness and lateralized cognitive functions. Information about lateralization in humans is also available from the post-cranial skeleton, particularly the arm bones, in which differences in size and shape are related to hand/arm preference. Our objective here is to characterize the possible correlations between the endocranial and post-cranial asymmetries of an archaeological sample. This, in turn, will allow us to try to identify and interpret prospective functional traits in the archaeological and fossil records. We observe that directional asymmetry (DA) is present both for some endocranial and humeral traits because of brain lateralization and lateralized behaviors, while patterns of fluctuating asymmetry (FA) vary. The combined study of these anatomical elements and of their asymmetries can shed light on the ways in which the body responds to dependent asymmetrical stimuli across biologically independent anatomical areas. Variations in FA are, in this context, indicators of differences in answers to lateralized factors. Humeri tend to show a much larger range of variation than the endocast. We show that important but complex information may be extracted from the combined study of the endocast and the arms in an archaeological sample of Homo sapiens.

Ankylosis of a knee joint from Medieval London: Trauma, congenital anomaly or osteoarthritis?

OBJECTIVE

To explore the differential diagnoses of a fused left knee joint and the subsequent impairment.

MATERIALS

An adult female skeleton from the Medieval cemetery of St Mary Spital (London, England).

METHODS

We employed digital radiography and macroscopic observation to record the changes observed throughout the skeleton. We also used the Index of Care to explore the subsequent impairment.

RESULTS

A range of congenital and developmental conditions were identified throughout the axial skeleton, with changes to the spine, pelvis, arms and leg bones reflecting adaptation to the mobility impairment.

CONCLUSIONS

In all probability, the left knee reflects a case of congenital ankylosis with a differential diagnosis of subadult trauma. The female's skeleton had adapted to the impairment. Their risk is likely to have been elevated because of climatic and pandemic events during this period.

SIGNIFICANCE

First reported case of congenital knee ankylosis.

LIMITATIONS

The left knee joint was damaged during excavation.

SUGGESTIONS FOR FURTHER RESEARCH

Additional imaging is advised.

The bioarchaeology of mid-Holocene pastoralist cemeteries west of Lake Turkana, Kenya

Early herders in eastern Africa built elaborate megalithic cemeteries ~ 5000 BP overlooking what is now Lake Turkana in northwestern Kenya. At least six 'pillar sites' were constructed during a time of rapid change: cattle, sheep, and goats were introduced to the basin as the lake was shrinking at the end of the African Humid Period. Cultural changes at this time include new lithic and ceramic technologies and the earliest monumentality in eastern Africa. Isolated human remains previously excavated from pillar sites east of Lake Turkana seemed to indicate that pillar site platforms were ossuaries for secondary burials. Recent bioarchaeological excavations at four pillar sites west of the lake have now yielded ≥49 individuals, most from primary and some from secondary interments, challenging earlier interpretations. Here we describe the mortuary cavities, and burial contexts, and included items such as adornments from Lothagam North, Lothagam West, Manemanya, and Kalokol pillar sites. In doing so, we reassess previous hypotheses regarding pillar site construction, use, and inter-site variability. We also present the first osteological analyses of skeletons buried at these sites. Although the human remains are fragmentary, they are nevertheless informative about the sex, age, and body size of the deceased and give evidence for health and disease processes. Periosteal moulds of long bone midshafts (n = 34 elements) suggest patterns of terrestrial mobility. Pillar site deposits provide important new insights into early herder lifeways in eastern Africa and the impact of the transition to pastoralism on past human populations.

Error in the estimation of periosteal and endosteal contours from micro-CT scans for nonadult tibiae and humeri

OBJECTIVES

This article summarized errors obtained by diverse techniques used for the derivation of cross-sectional contours in nonadult humeri and tibiae.

MATERIALS AND METHODS

We analyzed cross-sectional contours in a total sample of 62 humeral and 75 tibial diaphyses in the age between birth and 12 years divided into three age groups. Long bone 35% (humeri) and midshaft (tibiae) cross-sections were taken on micro-CT images and analyzed by EPJMacro in FIJI. Properties were extracted from contours derived by manual, automatic, spline, and ellipse techniques. Agreement between techniques was assessed using manually extracted properties such as the true value using percent prediction error (%PE), reduced major axis regression, and ±95% limits of agreement.

RESULTS

The lowest measurement errors were obtained for total areas, moderate errors for cortical areas and section moduli, and the highest errors for medullary areas for both bones. Derivation of humeral nonadult cross-sectional properties is less sensitive to the technique used for derivation of periosteal and endosteal contours, reaching mean %PEs below 5%. In contrast, tibial nonadult cross-sectional properties are more sensitive to the technique used and exceed 5% for some combinations.

DISCUSSION

Automatic techniques provide reasonably high agreement with manually extracted contours for nonadult humeri but low agreement for tibiae. Semiautomatic approaches-spline and ellipse techniques-may reduce the error for all studied properties in tibiae, especially when combined with manually traced periosteal contours. The positive effect of the semiautomatic technique on measurement error is low for humeri.

Maintaining mobility after fracture: A biomechanical analysis of fracture consequences at the Roman Sites of Ancaster (UK) and Vagnari (Italy)

OBJECTIVE

This study uses biomechanical data from tibiae to investigate the functional consequences of lower limb fractures. Adults with malunited fractures are hypothesized to have experienced altered mobility, indicated by asymmetric tibial cross-sectional geometries (CSG).

MATERIALS

Ninety-three adults from Roman (1st to 4th centuries CE) Ancaster, UK and Vagnari, Italy (Ancaster n = 16 adults with lower limb fracture:53 without fracture; Vagnari n = 5:19) METHODS: Biplanar radiographs were used to quantify and compare tibial CSG properties and asymmetries between individuals with and without fractures to femora, tibiae, and/or fibulae. The amount of angulation, rotation, and overlap, indicative of linear deformity, were measured for each fracture. Individuals who loaded their fractured leg differently than their opposite, uninjured leg were identified using outlying amounts of CSG asymmetry.

RESULTS

Two Ancaster individuals had poorly aligned fractures. None of the Ancaster or Vagnari individuals with lower limb fractures had CSG properties or asymmetries outside the calculated normal ranges.

CONCLUSIONS

Regardless of how a fracture healed, individuals at Ancaster and Vagnari generally resumed mobility after trauma whenever possible.

SIGNIFICANCE

This research contributes information about injury recovery and suggests that resilient behaviors and persistent mobility may have been valued or required responses to fracture in the study communities. This work advises that impairment should not be inferred based solely on the appearance of lesions.

LIMITATIONS

Site, sex, and age patterns in injury recovery are not evaluated due to sample size limitations.

SUGGESTIONS FOR FURTHER RESEARCH

Biomechanical assessments of post-traumatic function in varied cultural contexts are advised in order to further characterize the impact that physical and social factors have on injury recovery.

The impact of terrain on lower limb bone structure

OBJECTIVES

Lower limb diaphyseal geometry is often used to evaluate mobility in past populations. Diaphyseal dimensions such as high shape (I_X /I_Y ) indices generally thought to reflect high mobility may also result from walking over rough terrain. This study investigates the possible effects of terrain on lower limb diaphyseal cross-sectional geometric dimensions.

MATERIALS

The sample (N = 3,195) comprises adult skeletons from Europe, Africa, North America, and Asia, spanning from around 30,000 BP to mid-twentieth century.

METHODS

Femoral and tibial shape and bending/torsional strength dimensions were gathered either as part of a previous project or were generously provided by researchers. Local terrain for each site was quantified with ArcGIS mapping software using geographic coordinates and USGS elevation data, and characterized as flat, hilly, or mountainous.

RESULTS

Analysis of variance shows significant differences (p < .05) in midshaft femoral and tibial shape ratio and relative bending/torsional strength among the three terrain categories, with more AP oriented diaphyseal shapes and greater relative strength in hilly and mountainous groups, even after correcting for the effect of subsistence. As expected, the impact of terrain is much more marked for hunter-gatherers and agriculturalists than for more mechanized recent populations. Interestingly, the effect of terrain is confounded in higher latitude individuals that exhibit increased ML bending strength, probably reflecting larger body breadth.

DISCUSSION

This study underscores the mechanical significance of traveling over rough terrain and highlights the complex interactions of mobility, terrain, and body shape that contribute to shaping lower limb bone diaphyseal structure.

Histomorphometry and cortical robusticity of the adult human femur

Recent quantitative analyses of human bone microanatomy, as well as theoretical models that propose bone microstructure and gross anatomical associations, have started to reveal insights into biological links that may facilitate remodeling processes. However, relationships between bone size and the underlying cortical bone histology remain largely unexplored. The goal of this study is to determine the extent to which static indicators of bone remodeling and vascularity, measured using histomorphometric techniques, relate to femoral midshaft cortical width and robusticity. Using previously published and new quantitative data from 450 adult human male (n = 233) and female (n = 217) femora, we determine if these aspects of femoral size relate to bone microanatomy. Scaling relationships are explored and interpreted within the context of tissue form and function. Analyses revealed that the area and diameter of Haversian canals and secondary osteons, and densities of secondary osteons and osteocyte lacunae from the sub-periosteal region of the posterior midshaft femur cortex were significantly, but not consistently, associated with femoral size. Cortical width and bone robusticity were correlated with osteocyte lacunae density and scaled with positive allometry. Diameter and area of osteons and Haversian canals decreased as the width of cortex and bone robusticity increased, revealing a negative allometric relationship. These results indicate that microscopic products of cortical bone remodeling and vascularity are linked to femur size. Allometric relationships between more robust human femora with thicker cortical bone and histological products of bone remodeling correspond with principles of bone functional adaptation. Future studies may benefit from exploring scaling relationships between bone histomorphometric data and measurements of bone macrostructure.

Cross-sectional properties of the humeral diaphysis of Paranthropus boisei: Implications for upper limb function

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.

The relationship of age, activity, and body size on osteoarthritis in weight-bearing skeletal regions

This study examined the simultaneous impact of multiple underlying factors on OA expression in weight-bearing joints of the vertebrae and lower limb of a modern European skeletal sample (Lisbon and Sassari). OA was evaluated using standard ranked categorical scoring; composite OA scores derived through principal component analysis. Body size was calculated from postcranial measurements; torsional strength (J) of the femoral midshaft was calculated from three-dimensional surface models, size standardized and used as a proxy for activity. A standard multiple regression was applied. In all regions, the linear combination of age, body mass, stature, and J was significantly related to differences in OA. Across all joints, age was the strongest predictor; neither body size, nor activity variables demonstrated a statistical relationship with OA at the lumbar or knee; J demonstrated a negative correlation with pelvic OA. Variation in OA can be explained by age, stature, body mass, and structural adaptation related to habitual use. The negative correlation between femoral torsional strength with OA suggests that long-term, repetitive physical work capacity in childhood may be protective against OA development later in life. The multifactorial aetiology of OA requires incorporating multiple lines of evidence to interpret individual or population health from bone samples.

Evidence for precision grasping in Neandertal daily activities

Neandertal manual activities, as previously reconstructed from their robust hand skeletons, are thought to involve systematic power grasping rather than precise hand movements. However, this interpretation is at odds with increasing archeological evidence for sophisticated cultural behavior. We reevaluate the manipulative behaviors of Neandertals and early modern humans using a historical reference sample with extensive genealogical and lifelong occupational documentation, in combination with a new and precise three-dimensional multivariate analysis of hand muscle attachments. Results show that Neandertal muscle marking patterns overlap exclusively with documented lifelong precision workers, reflecting systematic precision grasping consistent with the use of their associated cultural remains. Our findings challenge the established interpretation of Neandertal behavior and establish a solid link between biological and cultural remains in the fossil record.

A diachronic examination of biomechanical changes in skeletal remains from Tombos in ancient Nubia

Using morphometric assessment, we diachronically analyse mechanical stress and limb function at the Tombos (modern Sudan) archaeological site through time and changing socioeconomic circumstances. Based on previous research, we expect that during the Third Intermediate/Napatan (c. 1070-656 BCE) people were larger and more physically active than in the New Kingdom (∼1400-1070 BCE). On the appendicular skeleton of adults 57 measurements were obtained on individuals from 67 discrete burials and 370 commingled skeletal elements. These raw measurements were analysed statistically. Individuals from the discrete burials were used to calculate body mass and estimate mechanical behaviour (torsional and bending rigidity of long bones) modeled using beam theory across several bones of the upper and lower limbs. Body mass estimates for both sexes show people during the Third Intermediate/Napatan period were statistically significantly larger. On the upper limb for both sexes, variation reflects joint stabilisation and actions of flexion and extension at the elbow and/or supination/pronation of the forearm. On the lower limb, females show variation related to weight bearing activities and foot flexion; male variation is related to weight bearing activities, joint movement and stabilisation. These data point to altered habitual behaviour and physical activity for both sexes at Tombos through time. Suggested causes for both sexes include increased agricultural activities, and for males increased granite quarrying and equestrian activities. Using analyses of multiple bones of the upper and lower limbs in conjunction with biomechanical analyses, this study demonstrates the importance of the examination of physical activities in past populations, highlighting changes that can occur with sociopolitical transitions.

Bilateral asymmetry of the humerus in Neandertals, Australian aborigines and medieval humans

OBJECTIVES

Bilateral asymmetry of diaphyseal shape and size may be a reflection of relative activity levels and patterns of habitual biomechanical stress in the upper arms of Neandertals and Homo sapiens. The main purpose of our study was to assess the level of directional asymmetry of humeral cross sections in Neandertals, recent Australian aborigines, and medieval farmers.

MATERIALS AND METHODS

Indices of directional and absolute asymmetry (%DA and %AA) of humeral cross-sectional properties in Neandertals and recent Homo sapiens were calculated. Evenly distributed semilandmarks around the external and internal borders of cortical bone were digitized in the course of computed tomography for analysis of shape differences between sides of the body.

RESULTS

The medieval farmers were characterized by significant %DA and %AA for polar second moment of area (J), ratio of maximum to minimum second moments of area, and ratio of antero-posterior to medio-lateral bending strength. In Australian aborigines, only J in males shows significant %DA and %AA, while Neandertals exhibit no significant asymmetry of any cross-sectional properties. Differences in cross-sectional shape between sides of the body were established in all three analyzed groups.

DISCUSSION

High levels of directional asymmetry of cross-sectional shape and properties in medieval farmers may be caused by the performance of more physically demanding tasks using one side of the body from an early age in that population. Various patterns of asymmetry in Neandertals and modern humans may be caused by different habitual behaviors during growth, eco-geographic patterns in body proportions, genetic factors, and differences in ontogeny.

Diaphyseal cross-sectional geometry of the metatarsal bones in the Jomon population

OBJECTIVES

This study aimed to investigate differences in the diaphyseal cross-sectional geometry (CSG) of the metatarsal bones (MTs) between two populations with different habitual activities: the Jomon hunter-gatherers and modern Japanese people.

MATERIALS AND METHODS

We evaluated the first through fifth MTs of 117 skeleton samples: 59 (33 men and 26 women) were obtained from Late and Final Jomon period archeological sites and 58 (31 men and 27 women) were from modern Japanese people. CSG properties were calculated at the mid-shaft of the MTs and the relative values of the polar section modulus (Z_p ) of each second-to-fifth MTs to first MTs were calculated. These variables were compared according to population and sex.

RESULTS

Many of the CSG properties of MTs, except first MTs, were higher in the Jomon population than in the modern Japanese population for both sexes. Additionally, the relative values of the Z_p of the MTs were higher in Jomon men and women than in modern Japanese men and women. Moreover, the Jomon population had sex-based differences in the ratio of the shape of third MTs and fourth MTs and the relative MTs value. Jomon women had elliptical third MTs and fourth MTs, and the relative Z_p values of the third-to-fifth MTs to first MTs were higher in Jomon women than in Jomon men.

DISCUSSION

Our result suggests that the habitual activity of the Jomon population placed heavy loads on the forefoot. This finding possibly relates to mediolateral forefoot loading that appears to be related to traversing uneven terrain.

A juvenile with compromised osteogenesis provides insights into past hunter-gatherer lives

The Late Archaic in northeastern North America (4500-2800 B.P.) pre-dates reliance on pottery and domesticated plants. It is thought to reflect a highly mobile, seasonal migratory foraging/hunting regimen. A juvenile skeleton with pervasive bone wasting and fragile jaws from the Hind Site (AdHk-1), ca. 3000 B.P., southwestern Ontario, provides evidence of the social context of her family group, including aspects of mobility and food management. The well-preserved bones and teeth are considered in bioarchaeological context. Radiographic, osteometric and cross-sectional geometric approaches to assessing musculoskeletal function are presented, plus differential diagnosis of the bone wasting condition. All bones of the probable female (aged approx. 16yr) show stunting and wasting. Wedged lower vertebral bodies, porous trabeculae, undeveloped bicondylar angles (femur) and abnormally low cortical long bone mass are consistent with chronically reduced ambulation. Few teeth remain in the dramatically resorbed alveoli; slight tooth wear and substantial calculus suggest a modified (soft) diet. Osteogenesis imperfecta type IV is the most probable etiology. The extended survival of this juvenile who may never have walked reflects collective care. The case provides evidence of a past lifeway that appears to have been organized around logistic mobility, including occupational stability and food storage.

Ultrasound Characterization of Bone Demineralization Using a Support Vector Machine

We propose an ultrasound-guided remote measurement technique, utilizing an acoustic radiation force beam as our excitation source and a receiving hydrophone, to assess non-invasively a bone's mechanical properties. Features, such as velocity, were extracted from the acoustic pressure received from the bone surface. The typical velocity of an intact bone (3540 m/s) was higher in comparison to that of a demineralized bone (2231 m/s). According to the receiver operating characteristic curve, the optimal velocity cutoff value of ≥3096 m/s yields 80% sensitivity and 82.61% specificity between intact and demineralized bone. Utilizing a support vector machine, the hours of bone demineralization were successfully classified with maximum accuracy >80% using 18% training data. The results indicate the potential application of our proposed technique and support vector machine for monitoring bone mechanical properties.

The characteristic mid-shaft cross-sectional shape of the ulna in Jomon hunter-gatherers

OBJECTIVES

The Jomon people were hunter-gatherers who inhabited the Japanese archipelago between 10,000 BC and 300 BC. Here, we focus on the mid-shaft cross-sectional shape of the ulna in the Jomon population and compare it with modern Japanese people.

MATERIALS AND METHODS

Jomon specimens, including 32 males and 22 females, were excavated from shell mound sites in the Pacific and Seto inland coastal area of Honshu island in the Japanese archipelago dated to the Late-to-Final Jomon phase (between 2,000 BC and 300 BC). Mid-shaft ulna cross-sectional shapes were compared with modern Japanese specimens (25 males, 21 females) using standard linear measurements and elliptic Fourier analysis (EFA). Differences from both sides of this element were compared using predicted handedness.

RESULTS

Linear measurements and EFA results show that ulna shape of both sexes within the Jomon population are relatively larger in the antero-posterior direction and have more developed posterior borders than modern Japanese males and females. No significant differences were observed between Jomon sexes based on the predicted dominant side, but differences were evident in the predicted nondominant side. At the same time, bilateral differences were recognized in Jomon females, because of a lower level of posterior border development in the predicted nondominant side compared to the dominant side.

DISCUSSION

Shape differences between Jomon people and modern Japanese can be explained by variation in the habitual loading of the ulna. Sexual dimorphism in ulna shape within the Jomon population suggests division of labor differences.

Effects of dietary chromium supplementation on muscle and bone mineral interaction in broiler chicken

The study was conducted to ascertain the effects of dietary chromium chloride (CrCl₃·6H₂O) supplementation on mineral interaction in blood serum, leg muscles and bones of broilers at 35^th day of age. For this purpose, ninety male broiler chicks were divided into three groups. One served as control (group I) while, the other two groups were supplemented with CrCl₃ (group II-12.5mg/Kg feed; group III-25mg/Kg feed) from 12 to 28days of age. In serum, Cr concentration remained non-significant however, Zn, and K concentrations decreased (P<0.05) with both levels of Cr-supplementation. Furthermore, in muscles Cr, Cu, Ca and Na levels remained non-significant but concentrations of Zn and K decreased (P<0.05) with feed Cr enrichment. Chromium had a substantial effect on femur and fibula Zn retention with 25mg/Kg feed supplementation while, Cr deposition decreased (P<0.05) in fibula. Femur Ca (P<0.002), Na (P<0.001) and K (P<0.05) retention was inversely proportional to both Cr concentrations in feed. In tibia, Cu and Na concentration decreased (P<0.002) with high dietary Cr supplementation. Fibular Ca and Na concentrations remained significantly (P<0.001) lower in Cr supplemented groups. Bone robusticity index was non-significant but ash to weight ratio of femur, tibia and fibula decreased (P<0.05) in group III. Chromium supplementation has a major effect on serum or muscle Zn and K deposition while bone mineral interaction shows a major thrust on Zn, Ca and Na levels.