Cross sectional properties of the human radial tuberosity

This study examines the cross sectional shape and biomechanical properties of the radial bone shaft at mid-radial tuberosity (RT) musculoskeletal marker (MSM). This information will provide insight into factors affecting bone modelling at muscle insertions. Radial shaft cross-sectional properties at radial tuberosity area (RTA) have not been previously studied. The material consists of 54 male skeletons derived from autopsies performed during the 1920s and 1930s and housed at the Central Natural History Museum, University of Helsinki. The age, sex and occupation of these individuals are known. We applied a pQCT (peripheral quantitative computed tomography) scan on the mid-site of the radial tuberosity to investigate the cross-sectional shape, the bone mineral density (BMD) and biomechanical properties. Our results indicate that bone modelling does not produce increased wall thickness or BMD at the RT site. Additionally we noticed that aging and physical activity affect the biomechanics of the RT and that the bone distribution at mid-RT is adapted to accommodate the biceps brachii muscle pull. We also found a clear association between RTA and biomechanical properties of mid-RT cross section.     

Second metacarpal midshaft geometry in an historic cemetery sample

Study of bone mass at the second metacarpal midshaft has contributed to our understanding of skeletal growth and aging within and between populations and has relied extensively on noninvasive techniques and in particular radiogrammetric data. This study reports age, sex, and side variation in size and shape data acquired from direct measurement of cross-sections obtained from a large (n = 356), homogeneous skeletal sample. Correlation analysis and three-way ANOVA of size-adjusted data confirm general impressions of patterned variation in this element: males have absolutely but not necessarily relatively larger bones than females; the right side is larger than the left, though a larger than expected proportion (approximately 25%) of left metacarpals exhibits greater values than the right; and bone mass but not strength (in males) declines with age. Contrary to the widely accepted assumption of circularity for this location, direct measurement of cross-sectional geometry confirms previous biplanar radiogrammetric conclusions regarding the noncircularity of the second metacarpal midshaft and identifies a significant difference between males and females, with the latter having a more cylindrical diaphysis. Deviation of the axes of maximum and minimum bending strength associated with noncircularity suggests a distribution of bone mass to resist bending moments perpendicular to the distal palmar arch, though this conclusion awaits more robust study of the functional anatomy of the metacarpal diaphysis. Am J Phys Anthropol 106:157–167, 1998. © 1998 Wiley-Liss, Inc.     

Trauma-induced changes in diaphyseal cross-sectional geometry in two elites from Copan, Honduras

This research utilized biplanar radiographs to estimate cross-sectional biomechanical properties for the skeletal remains of two elite individuals from the Early Classic period (ca. AD 400-600) of Copan, Honduras: K'inich Yax K'uk' Mo' (Hunal Burial 95-2), founder of the Early Classic Dynasty at Copan, and the primary female interment (Burial 37-8) from the Motmot tomb. Both individuals survived severe blunt-force insults to the right forearm. Gross skeletal examination and evaluation of the radiographs for K'inich Yax K'uk' Mo' suggest that these traumas resulted from, at least in part, disuse atrophy of the affected forearm skeletal elements. Gross and radiologic evaluation of the Motmot remains countered the possibility that she suffered from a metabolic bone disease, and confirmed the presence of a well-healed parry fracture of the right ulna. The degree of asymmetry in cross-sectional biomechanical properties reported here for K'inich Yax K'uk' Mo' is likely the secondary result of the described blunt-force trauma. The results obtained for the principal Motmot interment are not as dramatic, but suggest subtle changes to humeral cross-sectional geometry subsequent to trauma.     

Tracing prehistoric activities: musculoskeletal stress marker analysis of a Stone-Age population on the island of Gotland in the Baltic sea

The skeletal remains from the Middle Neolithic (2750-2300 BC) burial ground at Ajvide, Gotland, are analyzed in order to explore musculoskeletal patterns and to attempt to trace general as well as three specific prehistoric activities (archery, harpooning, and kayaking) that are likely to have been performed in this marine setting of fishing, hunting, and gathering. Scoring of muscular and ligament attachments is performed using the scoring method of Hawkey and Merbs ([1995] Int. J. Osteoarchaeol. 5:324-338) for muskuloskeletal stress markers (MSM). The skeletal material consists of 24 male and 15 female adult individuals divided into three age groups: young (<24 years), middle (25-39 years), and old (>40 years). Thirty upper body MSM sites, on both the left and right sides, are scored and form the basis of the study. Results show that males most frequently have higher mean MSM scores than females. Bilateral asymmetry was noted as low in both sexes. Age proved to be a contributing factor to increased MSM scores, with a greater age-related increase in females. MSM patterns were analyzed statistically in muscle groups associated with the three investigated activities. Significant positive correlations were observed in male individuals in muscle groups associated with archery and to some extent harpooning, an indication that these activities would mainly have been performed by men. Correlations in kayaking muscles were not evidently consistent with the kayaking motion. Furthermore, the costoclavicular ligament, often referred to in connection with "kayaker's clavicle," showed no positive statistical correlation with the kayaking muscles.     

Effects of age and occupation on cortical bone in a group of 18th-19th century British men

The effects of age and occupation on cortical bone in a group of adult males from the 18th-19th century AD skeletal collection from Christ Church Spitalfields, London, were investigated. Cortical bone was monitored using metacarpal radiogrammetry. Individual age at death was known exactly from coffin plates. Occupation for individuals was known from historical sources. Results showed that continued periosteal apposition was evident throughout adult life, but from middle age onwards this was outstripped by about 2:1 by endosteal resorption, so that there was net thinning of cortical bone. The rate of cortical thinning resembled that seen in modern European males. Cross-sectional properties, as measured by second moments of area, bore no relationship to occupation. The results may suggest that, firstly, patterns of loss of cortical bone have remained unchanged in males for at least two centuries in Britain, and secondly, that biomechanical analyses of metacarpal cortical bone may be rather insensitive indicators of intensity of manual activity.     

Linking structural variability in long bone diaphyses to habitual behaviors: foragers from the southern African Later Stone Age and the Andaman Islands

The cross-sectional distribution of cortical bone in long bone diaphyses is highly responsive to mechanical loading during life, yet the relationship between systemic and localized influences on skeletal structure remains unclear. This study investigates postcranial robustness throughout the body among adults from two groups of foragers with different patterns and modes of mobility, to determine whether there is evidence for upper vs. lower body localization of skeletal robustness. The samples used for this comparison are from the southern African Later Stone Age (LSA; n = 65, male = 33, female = 28) dating from ca. 10,000 to 2,000 B.P., and 19th century indigenous Andaman Islanders (AI; n = 36, male = 17, female = 16). The LSA were highly mobile foragers who did not exploit offshore marine resources. In contrast, the AI had tightly constrained terrestrial, but significant marine, mobility. Geometric properties of cortical bone distribution in the diaphyses of the clavicle, humerus, femur, tibia, and first metatarsal are compared between the samples, providing a representation of skeletal robustness throughout the body. Multivariate ANOVA shows the AI to have significantly stronger clavicles and humeri, while the LSA femora, tibiae, and first metatarsals are stronger than those of the AI. These patterns, in which upper and lower limbs show biomechanical properties that are consistent with habitual behaviors, suggest localized osteogenic response. Although postcranial robustness appears to be correlated with overall limb function, the results suggest that more proximal elements within the limb may be more responsive to mechanical loading.     

Musculoskeletal stress markers in Natufian hunter-gatherers and Neolithic farmers in the Levant: the upper limb

This paper attempts to quantify the changes in activity patterns of early farming populations in the Levant through the musculoskeletal stress markers (MSM) of the upper limb as seen in skeletal remains. The transition to an agricultural way of life resulted in higher loads on the upper limb in Neolithic populations compared to the Natufian hunter-gatherer populations that preceded them. The MSM pattern for males and females indicates a gender-based division of labor both in the Natufian and the Neolithic. It may also suggest that people in the Neolithic period were engaged in different (new) activities and occupations compared to the Natufian.     

Enthesopathies as occupational stress markers: Evidence from the upper limb

Enthesopathies—that is, “musculo‐skeletal stress markers”—are frequently used to reconstruct past lifestyles and activity patterns. Relatively little attention has been paid in physical anthropology to methodological gaps implicit in this approach: almost all methods previously employed neglect current medical insights into enthesopathies and the distinction between healthy and pathological aspects has been arbitrary. This study presents a new visual method of studying fibrocartilaginous enthesopathies of the upper limb (modified from Villotte: Bull Mém Soc Anthropol Paris n.s. 18 (2006) 65–85), and application of this method to 367 males who died between the 18th and 20th centuries, from four European identified skeletal collections: the Christ Church Spitalfields Collection, the identified skeletal collection of the anthropological museum of the University of Coimbra, and the Sassari and Bologna collections of the museum of Anthropology, University of Bologna. The analysis, using generalized estimating equations to model repeated binary outcome variables, has established a strong link between enthesopathies and physical activity: men with occupations involving heavy manual tasks have significantly (P‐value < 0.001) more lesions of the upper limbs than nonmanual and light manual workers. Probability of the presence of an enthesopathy also increases with age and is higher for the right side compared with the left. Our study failed to distinguish significant differences between the collections when adjusted for the other effects. It appears that enthesopathies can be used to reconstruct past lifestyles of populations if physical anthropologists: 1) pay attention to the choice of entheses in their studies and 2) use appropriate methods. Am J Phys Anthropol, 2010. © 2009 Wiley‐Liss, Inc.     

Computed tomography and automated image analysis of prehistoric femora

Non-invasive characterization of limb bone cross-sectional geometry would be useful for biomechanical analyses of skeletal collections. Computed tomography (CT) is potentially the method of choice. Additionally, CT images are suitable for automated analysis. CT is here shown to be both accurate and precise in the analysis of cross-sectional geometry of prehistoric femora. Beam hardening artifacts can be reduced by using a water bath. As the availability of CT for research increases, both bone density and geometry could be determined simultaneously with this method.     

The effect of age, sex, and physical activity on entheseal morphology in a contemporary Italian skeletal collection

Entheseal changes are traditionally included in a large array of skeletal features commonly referred to as "skeletal markers of activity." However, medical studies and recent anthropological analyses of identified skeletal series suggest a complex combination of physiological and biomechanical factors underlying the variability of such "markers." The aim of this study is to examine the relationship between age, sex, physical activity, and entheseal variability. To this end, 23 postcranial entheses are examined in a large (N = 484) Italian contemporary skeletal series using standardized scoring methods. The sample comprises subjects of known age, sex and, mostly, occupation. Results show a strong relationship between age and entheseal changes. Differences between sexes are also highlighted, while the effects of physical activity appear moderate. Altogether, our study indicates that entheseal morphology primarily reflects the age of an individual, while correlation with lifetime activity remains ambiguous.     

Enthesopathy formation in the humerus: Data from known age‐at‐death and known occupation skeletal collections

Enthesopathies, in the guise of musculoskeletal skeletal stress markers (MSM), have been widely used to reconstruct activity levels in human skeletal populations. In general, studies have focused on their presence in the upper limb, which is used in the majority of daily activities. The aim of this study was to use some of the attachment sites on the humerus to explore the relationship between enthesopathy formation, activity, and the ageing process. The skeletal sample used in this study comprised male adult skeletons with known age‐at‐death and known occupations from the late‐19th and early‐20th century cemeteries in Portugal. The enthesopathies were recorded as either present or absent. Statistical analysis using Fishers exact tests and logistic regression was undertaken to determine whether associations could be found between specific activities or socioeconomic status (manual or nonmanual workers), and age and enthesopathy presence. Left and right sides were analyzed separately. Fisher's exact tests were used to determine the relationship between activity and enthesopathy, and they demonstrated no association between activity and enthesopathies (P > 0.01). The results of the logistic regression established that age was the single most significant factor in enthesopathy formation (P > 0.05). This study found that, in these samples, age‐at‐death, and therefore age‐related degeneration rather than degeneration caused by activities, was the primary cause of enthesopathy formation. Considering the difficulties of reliably ageing adult human skeletal remains, this is a major issue for studies of activity using enthesopathies. Am J Phys Anthropol, 2010. © 2009 Wiley‐Liss, Inc.     

Divergence in Male and Female Manipulative Behaviors with the Intensification of Metallurgy in Central Europe

Humeral morphology has been shown to reflect, in part, habitual manipulative behaviors in humans. Among Central European agricultural populations, long-term social change, increasing task specialization, and technological innovation all had the potential to impact patterns of habitual activity and upper limb asymmetry. However, systematic temporal change in the skeletal morphology of agricultural populations in this region has not been well-characterized. This study investigates diachronic patterns in humeral biomechanical properties and lengths among 174 adult Central European agriculturalists through the first ∼5400 years of farming in the region. Greater asymmetry in biomechanical properties was expected to accompany the introduction of metallurgy, particularly in males, while upper limb loading patterns were expected to be more similar between the Bronze and Iron Ages. Results revealed a divergence in the lateralization of upper limb biomechanical properties by sex between the Early/Middle Neolithic and Early/Middle Bronze Age. Neolithic females had significantly more variable properties than males in both humeri, while Bronze Age female properties became homogeneous and very symmetrical relative to the right-biased lateralization of contemporaneous males. The Bronze Age to Iron Age transition was associated with morphological change among females, with a significant increase in right-biased asymmetry and a concomitant reduction in sexual dimorphism. Relative to biomechanical properties, humeral length variation and asymmetry were low though some significant sexual dimorphism and temporal change was found. It was among females that the lateralization of humeral biomechanical properties, and variation within them, changed most profoundly through time. This suggests that the introduction of the ard and plow, metallurgical innovation, task specialization, and socioeconomic change through ∼5400 years of agriculture impacted upper limb loading in Central European women to a greater extent than men.     

Advanced Glycation Endproducts and Bone Material Properties in Type 1 Diabetic Mice

Fractures, particularly at the lower extremities and hip, are a complication of diabetes. In both type 1 (T1D) and type 2 diabetes (T2D), fracture risk is disproportionately worse than that predicted from the measurement of bone mineral density. Although an explanation for this discrepancy is the presence of organic matrix abnormalities, it has not been fully elucidated how advanced glycation endproducts (AGEs) relate to bone deterioration at both the macroscopic and microscopic levels. We hypothesized that there would be a relationship between skeletal AGE levels (determined by Raman microspectroscopy at specific anatomical locations) and bone macroscopic and microscopic properties, as demonstrated by the biomechanical measures of crack growth and microindentation respectively. We found that in OVE26 mice, a transgenic model of severe early onset T1D, AGEs were increased by Raman (carboxymethyl-lysine [CML] wildtype (WT): 0.0143 ±0.0005 vs T1D: 0.0175 ±0.0002, p = 0.003) at the periosteal surface. These differences were associated with less tough bone in T1D by fracture mechanics (propagation toughness WT: 4.73 ± 0.32 vs T1D: 3.39 ± 0.24 NM/m^1/2, p = 0.010) and by reference point indentation (indentation distance increase WT: 6.85 ± 0.44 vs T1D: 9.04 ± 0.77 μm; p = 0.043). Within T1D, higher AGEs by Raman correlated inversely with macroscopic bone toughness. These data add to the existing body of knowledge regarding AGEs and the relationship between skeletal AGEs with biomechanical indices.     

Diachronic patterns of change in structural properties of the femur in the prehistoric American Southwest

Diachronic patterns of change in the femoral diaphysis are examined in archaeological skeletal samples from the American Southwest. Three cultural periods differing in subsistence-settlement strategies are represented: Early Villages (A.D. 500-1150), Abandonments (A.D. 1150-1300), and Aggregated Villages (A.D. 1300-1540). Relevant properties of cross-sectional geometry and bone density were obtained using computerized tomography. Temporal trends in geometry suggest that activity levels increased between Early Villages and Abandonments, then declined during Aggregated Villages. In both sexes, femoral shape became more circular, and bending stresses were reduced in the a-p plane through time. Compared to the other periods, bone density was the lowest during Abandonments in both sexes. The reduction in bone density may reflect declining nutritional quality through time that was especially poor during the Abandonments period. Patternings in sexual dimorphism suggest that Abandonments males may have been more sensitive to nutritional stress than contemporary females.     

The effects of total hip arthroplasty on the structural and biomechanical properties of adult bone

The responsiveness of bone to mechanical stimuli changes throughout life, with adaptive potential generally declining after skeletal maturity is reached. This has led some to question the importance of bone functional adaptation in the determination of the structural and material properties of the adult skeleton. A better understanding of age-specific differences in bone response to mechanical loads is essential to interpretations of long bone adaptation. The purpose of this study is to examine how the altered mechanical loading environment and cortical bone loss associated with total hip arthroplasty affects the structural and biomechanical properties of adult bone at the mid-shaft femur. Femoral cross sections from seven individuals who had undergone unilateral total hip arthroplasty were analyzed, with intact, contralateral femora serving as an approximate internal control. A comparative sample of individuals without hip prostheses was also included in the analysis. Results showed a decrease in cortical area in femora with prostheses, primarily through bone loss at the endosteal envelope; however, an increase in total cross-sectional area and maintenance of the parameters of bone strength, I(x), I(y), and J, were observed. No detectable differences were found between femora of individuals without prostheses. We interpret these findings as an adaptive response to increased strains caused by loading a bone previously diminished in mass due to insertion of femoral prosthesis. These results suggest that bone accrued through periosteal apposition may serve as an important means by which adult bone can functional adapt to changes in mechanical loading despite limitations associated with senescence.     

Biomechanical beam analysis of long bones from a late 18th century slave cemetery in Cape Town, South Africa

This study aims to quantify the physical demands of a sample of late 18th century skeletons from an unmarked burial site on Cobern Street, Cape Town, South Africa. Historical studies suggest that these individuals were either slaves or "free black" people of low socioeconomic standing. Cortical cross-sectional areas of paired humeri and tibiae from the Cobern Street collection (N = 29), a modern cadaver collection (N = 31), and a hunter-gatherer collection (N = 30) were compared by means of biomechanical beam analysis on computerized tomography scans. Results showed that the Cobern Street sample, both males and females, were closer to the modern group in total tibial cortical area and in the second moments and polar moments of cortical area, than to the hunter-gatherer group. It is assumed that these results can be explained by differences in lower limb activity. Tibial strength properties showed the hunter-gatherer peoples to be highly mobile and active walkers in comparison to the Cobern Street and modern samples. The males from the Cobern Street sample showed significantly higher values for humeral strength properties than either the hunter-gatherer or modern individuals, attesting to their status as manual laborers. The humeral cross-sectional strength properties for females were very similar between the Cobern Street and modern groups but again significantly different from the hunter-gatherer sample. The domestic chores performed by females of the recent cadaver sample may be very similar to those performed by the Cobern Street sample.     

辽宁建平古人类肱骨形态结构分析

1957年,在辽宁省建平县发现了一根古人类肱骨化石,编号PA103。通过同一批龙骨中筛选的哺乳动物化石,吴汝康推断PA103应该为更新世晚期古人类,并对该化石进行了表面形态特征观察和描述。为了对PA103化石的内外结构进行更全面的了解,除了线性测量数据的对比,本文还通过计算机断层扫描技术,结合生物力学和形态示量图分析对建平古人类右侧肱骨化石PA103进行了分析。通过本研究发现,PA103骨干横断面的生物力学粗壮度和力学形状指数明显小于尼安德特人,而与同时期欧亚大陆古人类不利手侧最为接近,这说明建平人右侧肱骨可能不是惯用手,同时,建平人的行为活动应该与同时期同地区的古人类处于同一水平,而小于尼安德特人。整体来看,PA103骨干骨密质厚度和截面惯性矩与近现代人的分布模式较为接近,除局部数值增大外,其整体数值小于近现代人的平均水平,这可能与遗传或行为活动有关,由于缺少古人类化石对比数据,更详细的了解还需后期开展更多相关的研究。     

Age, sex, and grip strength determine architectural bone parameters assessed by peripheral quantitative computed tomography (pQCT) at the human radius

The purpose of this study was to estimate the relation of some noninvasively derived mechanical characteristics of radial bone including architectural parameters for bone strength to grip strength and muscle cross-section. Sixty-three males between 21 and 78yr of age and 101 females between 18 and 80yr of age were measured at the nondominant forearm using peripheral quantitative computed tomography (pQCT). We assessed the integral bone mineral density (BMD(I)) and content (BMC(I)) by pQCT at the distal and at the mid-shaft radius. Integral bone area (Area(I)), cortical thickness (C-th), and a newly proposed index for bone strength; the stress-strain index (SSI) were also calculated. The dynamometrically measured maximum grip strength was taken as a mechanical loading parameter and muscle cross-section as a substitute for it. Sex, grip strength, BMC(I) and BMD(I) (distal radius) were identified in a multiple regression analysis to significantly predict bone strength as expressed by SSI, after adjusting for all other independent variables, including age and sex (p<0.0001). Grip strength was closest related to age, sex, BMD(I) and SSI(p) of the distal radius. The cross-sectional area of muscle was not significantly determining the grip strength within the analysis model. In conclusion, our results suggested that architectural parameters at the distal radius were better related to grip strength than to cross-sectional muscle area in both males and females. Maximum muscle strength as estimated by grip strength might be a stronger determinant of mechanical characteristics of bones as compared with cross-sectional muscle area.     

Cross-Sectional and Prospective Associations between Physical Activity and C-Reactive Protein in Males

BackgroundThere is conflicting evidence about the association between physical activity and inflammatory markers. Few prospective studies are available, particularly from low and middle-income countries. This study was aimed at assessing the cross-sectional and prospective associations between physical activity and C-reactive protein (CRP) levels in males belonging to the 1982 Pelotas (Brazil) Birth Cohort Study.MethodsThe sample comprised 2,213 males followed up at the ages of 18 and 23 years. We performed high sensitivity CRP assays; we used a cut-off of 3 mg/L in categorical analyses. We measured physical activity by self-report at ages 18 and 23 years. Body mass index and waist circumference were studies as possible mediators.ResultsCRP levels above the 3mg/L cut-off were found in 13.3% (95%CI: 11.7; 14.8) of the individuals. We found no evidence for an association between physical activity (leisure-time or all-domains) and either continuous (geometrical mean) or categorical CRP. We confirmed these null findings in (a) prospective and cross-sectional analyses; (b) trajectories analyses.ConclusionsThere was no association between CRP levels and physical activity levels in early adulthood in a large birth cohort. Little variability in CRP at this early age is the likely explanation for these null findings.     

Hunter-gatherer postcranial robusticity relative to patterns of mobility, climatic adaptation, and selection for tissue economy

Human skeletal robusticity is influenced by a number of factors, including habitual behavior, climate, and physique. Conflicting evidence as to the relative importance of these factors complicates our ability to interpret variation in robusticity in the past. It remains unclear how the pattern of robusticity in the skeleton relates to adaptive constraints on skeletal morphology. This study investigates variation in robusticity in claviculae, humeri, ulnae, femora, and tibiae among human foragers, relative to climate and habitual behavior. Cross-sectional geometric properties of the diaphyses are compared among hunter-gatherers from southern Africa (n = 83), the Andaman Islands (n = 32), Tierra del Fuego (n = 34), and the Great Lakes region (n = 15). The robusticity of both proximal and distal limb segments correlates negatively with climate and positively with patterns of terrestrial and marine mobility among these groups. However, the relative correspondence between robusticity and these factors varies throughout the body. In the lower limb, partial correlations between polar second moment of area (J(0.73)) and climate decrease from proximal to distal section locations, while this relationship increases from proximal to distal in the upper limb. Patterns of correlation between robusticity and mobility, either terrestrial or marine, generally increase from proximal to distal in the lower and upper limbs, respectively. This suggests that there may be a stronger relationship between observed patterns of diaphyseal hypertrophy and behavioral differences between populations in distal elements. Despite this trend, strength circularity indices at the femoral midshaft show the strongest correspondence with terrestrial mobility, particularly among males.