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Forensic Science International May 2016Histomorphometric studies have reported relations between osteon size and age; however, data focused on the shape of osteons is sparse. The purpose of this study was to...
Histomorphometric studies have reported relations between osteon size and age; however, data focused on the shape of osteons is sparse. The purpose of this study was to determine how osteon circularity (On.Cr) varies with age in different skeletal elements. Regression analysis was used to evaluate the relationship between age and osteon shape and size. We hypothesized that age would be negatively related to osteon size (area, On.Ar) and positively related to osteon shape (On.Cr). On.Cr and On.Ar were determined for the ribs and femora of 27 cadaveric specimens with known age-at-death. As predicted, age was significantly related to osteon size and shape for both the femur and rib. With age, there was a decrease in size and an increase in circularity. No relationship between sex and On.Cr was detected. An age predicting model, including On.Cr, On.Ar and OPD, is proposed to improve our ability to estimate age-at-death, especially for older individuals.
Topics: Adult; Age Determination by Skeleton; Aged; Aged, 80 and over; Female; Femur; Forensic Anthropology; Haversian System; Humans; Male; Microscopy; Middle Aged; Regression Analysis; Ribs
PubMed: 27021159
DOI: 10.1016/j.forsciint.2016.02.053 -
American Journal of Physical... Apr 2017Histomorphological analyses of bones are used to estimate an individual's chronological age, interpret a bone's load history, and differentiate species. Among various...
OBJECTIVES
Histomorphological analyses of bones are used to estimate an individual's chronological age, interpret a bone's load history, and differentiate species. Among various histomorphological characteristics that can influence mechanical properties of cortical bone, secondary osteon (Haversian system) population density and predominant collagen fiber orientation are particularly important. Cross-sectional shape characteristics of secondary osteons (On.Cr = osteon circularity, On.El = osteon ellipticality) are considered helpful in these contexts, but more robust proof is needed. We sought to determine if variations in osteon shape characteristics are sufficient for accurately differentiating species, load-complexity categories, and regional habitual strain-mode distributions (e.g., tension vs. compression regions).
MATERIALS AND METHODS
Circularly polarized light images were obtained from 100-micron transverse sections from diaphyses of adult deer calcanei; sheep calcanei, radii, and tibiae; equine calcanei, radii, and third metacarpals (MC3s); chimpanzee femora; and human femora and fibulae. Osteon cross-sectional area (On.Ar), On.Cr, and On.El were quantified indiscriminately and in the contexts of load-complexity and regional strain-mode distributions.
RESULTS
On.Cr and On.El, when examined independently in terms of all data, or mean (nested) data, for each bone, exceeded 80% accuracy in the inter-species comparisons only with respect to distinguishing humans from nonhumans. Correct classification among the nonhuman species was <70%. When On.Cr and On.El were coupled together and with On.Ar in discriminant function analyses (nested and unnested data) there were high misclassifications in all but human vs. nonhuman comparisons.
DISCUSSION
Frequent misclassifications in nonhuman comparisons might reflect influences of habitual load complexity and/or strain-mode distributions, or other factors not accounted for by these two considerations.
Topics: Anatomy, Cross-Sectional; Animals; Deer; Diaphyses; Femur; Haversian System; Humans; Pan troglodytes; Sheep; Species Specificity; Tibia; Weight-Bearing
PubMed: 28121024
DOI: 10.1002/ajpa.23154 -
Calcified Tissue International Jan 2004As research into bone maintenance and turnover is accelerated and expanded due to public health concerns about osteoporosis and other age-related changes and pathologies... (Comparative Study)
Comparative Study
As research into bone maintenance and turnover is accelerated and expanded due to public health concerns about osteoporosis and other age-related changes and pathologies of bone, nonhuman animal models are becoming increasingly important as they allow for enhanced experimental manipulation and environmental control relative to humans. Old World Monkeys, such as the rhesus macaque, share physiological and developmental characteristics that make these primates particularly well suited to such studies. The purpose of this study was to characterize normal age and sex variation in osteon remodeling dynamics in skeletally immature and mature rhesus macaques. Femoral cross-sections from 75 Macaca mulatta were examined to evaluate the effect of age, sex, and skeletal maturity on osteon remodeling dynamics in this popular research primate. Results indicate that sex has a significant effect on osteon area (On.Ar), but generally is not an important contributor to normal variation in intracortical remodeling dynamics. Age and skeletal maturity, however, contribute significantly to variation in osteon population density (OPD), activation frequency (Ac.f), and bone formation rate (BFR), as is the case in humans. This study is the first to characterize normal age and sex variation in osteon remodeling in growing and adult rhesus macaques and its results support the use of this animal as a model for age-related changes and pathologies in the human skeleton.
Topics: Age Factors; Analysis of Variance; Animals; Bone Development; Bone Remodeling; Female; Haversian System; Macaca mulatta; Male; Sex Factors
PubMed: 14973638
DOI: 10.1007/s00223-003-9038-3 -
Journal of Structural Biology Feb 2013In bone, matrix slippage that occurs at cement lines of secondary osteons during loading is an important toughening mechanism. Toughness can also be enhanced by... (Comparative Study)
Comparative Study
In bone, matrix slippage that occurs at cement lines of secondary osteons during loading is an important toughening mechanism. Toughness can also be enhanced by modifications in osteon cross-sectional size (diameter) for specific load environments; for example, smaller osteons in more highly strained "compression" regions vs. larger osteons in less strained "tension" regions. Additional osteon characteristics that enhance toughness are distinctive variations in collagen/lamellar organization (i.e., "osteon morphotypes"). Interactions might exist between osteon diameter and morphotype that represent adaptations for resisting deleterious shear stresses that occur at the cement line. This may be why osteons often have a peripheral ring (or "hoop") of highly oblique/transverse collagen. We hypothesized that well developed/distinct "hoops" are compensatory adaptations in cases where increased osteon diameter is mechanically advantageous (e.g., larger osteons in "tension" regions would have well developed/distinct "hoops" in order to resist deleterious consequences of co-existing localized shear stresses). We tested this hypothesis by determining if there are correlations between osteon diameters and strongly hooped morphotypes in "tension", "compression", and "neutral axis" regions of femora (chimpanzees, humans), radii (horse, sheep) and calcanei (horse, deer). The results reject the hypothesis-larger osteons are not associated with well developed/distinct "hoops", even in "tension regions" where the effect was expected to be obvious. Although osteon diameter and morphotype are not coupled, osteon diameters seem to be associated with increased strain magnitudes in some cases, but this is inconsistent. By contrast, osteon morphotypes are more strongly correlated with the distribution of tension and compression.
Topics: Adaptation, Physiological; Analysis of Variance; Animals; Biomechanical Phenomena; Birefringence; Bone and Bones; Collagen; Deer; Haversian System; Horses; Humans; Pan troglodytes; Shear Strength; Sheep
PubMed: 23123271
DOI: 10.1016/j.jsb.2012.10.013 -
Journal of Orthopaedic Research :... May 2003An important concept in bone mechanics is that osteons influence mechanical properties in several ways, including contributing to toughness and fatigue strength by...
An important concept in bone mechanics is that osteons influence mechanical properties in several ways, including contributing to toughness and fatigue strength by debonding from the interstitial matrix so as to "bridge" developing cracks. Observations of "pulled out" osteons on fracture surfaces are thought to be indicative of such behavior. We tested the hypothesis that osteon pullout varies with mode of loading (fatigue vs. monotonic), cortical region, elastic modulus, and fatigue life. Mid-diaphseal beams from the dorsal, medial, and lateral regions of the equine third metacarpal bone were fractured in four point bending by monotonic loading to failure under deflection control, with or without 10(5) cycles of previous fatigue loading producing 5000 microstrain (15-20% of the expected failure strain) on the first cycle; or sinusoidal fatigue loading to failure, under load or deflection control, with the initial cycle producing 10,000 microstrain (30-40% of the expected failure strain). Using scanning electron microscopy, percent fracture surface area exhibiting osteon pullout (%OP.Ar) was measured. Monotonically loaded specimens and the compression side of fatigue fracture surfaces exhibited no osteon pullout. In load-controlled fatigue, pullout was present on the tension side of fracture surfaces, was regionally dependent (occurring to a greater amount dorsally), and was correlated negatively with elastic modulus and positively with fatigue life. Regional variation in %OP.Ar was also significant for the pooled (load and deflection controlled) fatigue specimens. %OP.Ar was nearly significantly greater in deflection controlled fatigue specimens than in load-controlled specimens (p=0.059). The data suggest that tensile fatigue loading of cortical bone eventually introduces damage that results in osteonal debonding and pullout, which is also associated with increased fatigue life via mechanisms that are not yet clear.
Topics: Animals; Bone Remodeling; Fractures, Stress; Haversian System; Horse Diseases; Horses; Metacarpus; Microscopy, Electron, Scanning; Weight-Bearing
PubMed: 12706021
DOI: 10.1016/S0736-0266(02)00232-2 -
American Journal of Physical... Apr 2020While double-zonal osteons (DZ) are characterized by a hyper-mineralized ring inside their lamellae, recent findings suggest that this ring is also defined by a change...
OBJECTIVES
While double-zonal osteons (DZ) are characterized by a hyper-mineralized ring inside their lamellae, recent findings suggest that this ring is also defined by a change in the collagen fibers' orientation. Collagen and minerals are essential components to the maintenance of adequate bone strength and their alteration can modify the mechanical properties of the bone tissue. Consequently, the aim of this study is to explore the effect of past loads, as estimated from cross-sectional geometric properties, on the formation of DZ osteons compared to type I (common) osteons.
MATERIALS AND METHODS
The sample consists of paired humerus and femur midshaft sections (n = 23) of Eurocanadian settlers from the historical St. Matthew cemetery, Quebec City (1771-1860). Histomorphometric variables included in this study are osteon density for DZ and type I osteons (DZD; OPD), osteon area (DZOn.Ar; On. Ar), Haversian canal area (DZH.Ar; H.Ar), and the area within the hypermineralized ring (HR. Ar). Loading history is estimated from cross-sectional properties including the following variable: cortical and total area (CA, TA), maximum and minimum second moment of area (I , I ) and polar moment of area (J).
RESULTS
When the humerus and femur of the same individuals are compared, the femur has a higher OPD, DZD, and relative DZD (DZD/OPD). DZ osteons have a smaller area and Haversian canal area compared to type I osteons. The area within the hypermineralized ring in DZ is higher than the Haversian canal area of the type I osteons. Correlations between the residual scores of the regression of histomorphometric variables and cross-sectional properties of the humerus on the femur were not significant.
DISCUSSION
Based on the analysis of the entire cross-section, the lack of correlation between variations in cross-sectional properties and remodeling combined with the significant differences between humeri and femura suggests that the creation of DZ or type I osteons in the bone tissue might be due to a bone specific response, possibly related to differences in bone tissue age that needs to be further investigated. Definitive conclusion regarding biomechanical loads still seem to be premature as regional variations associated with mechanical properties remain to be explored.
Topics: Adult; Biomechanical Phenomena; Cemeteries; Femur; Haversian System; History, 18th Century; History, 19th Century; Humans; Humerus; Middle Aged; Quebec; Young Adult
PubMed: 31675105
DOI: 10.1002/ajpa.23954 -
American Journal of Physical... May 1981Living adult Eskimos from St. Lawrence Island, North Alaska, and Canada undergo an earlier and more rapid rate of age-related bone mineral loss compared to U.S. whites.... (Comparative Study)
Comparative Study
Living adult Eskimos from St. Lawrence Island, North Alaska, and Canada undergo an earlier and more rapid rate of age-related bone mineral loss compared to U.S. whites. Further, it has been shown that Eskimos and Indians differ in patterns of osteon remodeling at the Haversian envelope. Femoral bone cores from adult Eskimos skeletons from St. Lawrence Island (n = 53), Kodiak Island (n = 92), Baffin Island (n = 44), and Southampton Island (n = 69) were analyzed and the results compared with those obtained from cores from U.S. whites (n = 144). Cortical thickness, bone mineral content of cores, cortical bone density, secondary osteon and Haversian canal number and area were quantified for each core. Ages at death were estimated by histological methods and compared with the ages at death estimated by morphological methods for the Eskimo skeletons. Known ages at death were compared with histologically estimated ages at death for the U.S. white series. St. Lawrence Island and Kodiak Island (Yupik speakers) Eskimo cortical thickness values were significantly (P less than .05) greater than Baffin Island and Southampton Island (Inupiaq speakers) Eskimos cortical thickness values but less than the cortical thickness values for U.S. whites. The bone mineral content of the Southampton Eskimos femoral cores was the lowest found in this study. Histological analysis of the femoral bone sections showed that Eskimos contain more osteons per unit area than U.S. whites. No differences in osteon size were noted between the two populations. Differences in patterns of osteon remodeling between Eskimos and whites were inferred. Age at death estimation by histological methods in Eskimos using U.S. white regression equations yielded age estimates in poor agreement with those obtained by morphological methods.
Topics: Age Determination by Skeleton; Bone and Bones; Female; Femur; Haversian System; Humans; Inuit; Male; Minerals; Specific Gravity; White People
PubMed: 7258331
DOI: 10.1002/ajpa.1330550102 -
Journal of Anatomy Oct 2011Cortical bone histology has been the subject of scientific inquiry since the advent of the earliest microscopes. Histology - literally the study of tissue - is a field...
Cortical bone histology has been the subject of scientific inquiry since the advent of the earliest microscopes. Histology - literally the study of tissue - is a field nearly synonymous with 2D thin sections. That said, progressive developments in high-resolution X-ray imaging are enabling 3D visualization to reach ever smaller structures. Micro-computed tomography (micro-CT), employing conventional X-ray sources, has become the gold standard for 3D analysis of trabecular bone and is capable of detecting the structure of vascular (osteonal) porosity in cortical bone. To date, however, direct 3D visualization of secondary osteons has eluded micro-CT based upon absorption-derived contrast. Synchrotron radiation micro-CT, through greater image quality, resolution and alternative contrast mechanisms (e.g. phase contrast), holds great potential for non-destructive 3D visualization of secondary osteons. Our objective was to demonstrate this potential and to discuss areas of bone research that can be advanced through the application of this approach. We imaged human mid-femoral cortical bone specimens derived from a 20-year-old male (Melbourne Femur Collection) at the Advanced Photon Source synchrotron (Chicago, IL, USA) using the 2BM beam line. A 60-mm distance between the target and the detector was employed to enhance visualization of internal structures through propagation phase contrast. Scan times were 1 h and images were acquired with 1.4-μm nominal isotropic resolution. Computer-aided manual segmentation and volumetric 3D rendering were employed to visualize secondary osteons and porous structures, respectively. Osteonal borders were evident via two contrast mechanisms. First, relatively new (hypomineralized) osteons were evident due to differences in X-ray attenuation relative to the surrounding bone. Second, osteon boundaries (cement lines) were delineated by phase contrast. Phase contrast also enabled the detection of soft tissue remnants within the vascular pores. The ability to discern osteon boundaries in conjunction with vascular and cellular porosity revealed a number of secondary osteon morphologies and provided a unique 3D perspective of the superimposition of secondary osteons on existing structures. Improvements in resolution and optimization of the propagation phase contrast promise to provide further improvements in structural detail in the future.
Topics: Femur; Haversian System; Humans; Imaging, Three-Dimensional; Male; Synchrotrons; X-Ray Microtomography; Young Adult
PubMed: 21644972
DOI: 10.1111/j.1469-7580.2011.01398.x -
Journal of Anatomy Jul 1965
Topics: Animals; Biometry; Bone Development; Bone and Bones; Cats; Haversian System; Microradiography; Microscopy, Fluorescence; Tetracycline
PubMed: 5857087
DOI: No ID Found -
American Journal of Physical... Jun 1998The possibility of smaller osteons in the cortical bone of Late Pleistocene human populations begs the question of how these histological features vary within individual...
The possibility of smaller osteons in the cortical bone of Late Pleistocene human populations begs the question of how these histological features vary within individual skeletons among and between populations. The distributional characteristics of total osteon area (On.Ar) and Haversian canal area (H.Ar) are explored using data from three samples of historically known individuals: ribs and femora from eighteenth-century Huguenots in England (Spitalfields, n = 20), ribs and femora from nineteenth-century British settlers in Canada (St. Thomas, n = 21), and ribs from twentieth-century South African cadavers (University of Cape Town; following curatorial classifications, n = 10 white, 10 black, 10 colored). Neither histological variable is normally distributed. About 96% of the random variation is within the individual bone sample. There are no significant differences between sexes for either variable in any sample, and age has no effect in most instances. Femoral osteons are significantly larger than rib osteons within individuals and across samples. Haversian canal area is more variable than On.Ar, especially in the twentieth-century sample, where within-sample coefficients of variation are frequently >100%. Using modern centiles developed here, some Late Pleistocene long bone samples have On.Ar values below the range of modern variation. Because of ribs' smaller cross-sectional areas and less broadly ranging values for On.Ar, ribs would provide a preferable site for future comparative studies.
Topics: Adolescent; Adult; Aged; Aged, 80 and over; Female; Femur; Haversian System; Humans; Male; Middle Aged; Paleontology; Reference Values; Ribs
PubMed: 9637185
DOI: 10.1002/(SICI)1096-8644(199806)106:2<219::AID-AJPA8>3.0.CO;2-K