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Acta of Bioengineering and Biomechanics 2016In this work, a finite element study is proposed by using the Comsol Multiphysics software to evaluate the effects of microcrack shape, size and direction on the...
PURPOSE
In this work, a finite element study is proposed by using the Comsol Multiphysics software to evaluate the effects of microcrack shape, size and direction on the poroelastic behaviors of a single osteon.
METHODS
This finite element model is established by using the Comsol Multiphysics software, and we just focus on the comparison of the influences of those microcrack geometric parameters on the osteonal fluid pressure and velocity.
RESULTS
The results show that: (1) microcracks in the osteon wall can induce a release of the fluid pressure, but enlarge the velocity in this region; (2) equal-area microcrack with ellipsoid-like shape produced a larger fluid pressure and velocity fields in the osteon than that of rectangular shape; (3) in the elliptic microcracks, the longer of the length (major semi-axis) induces a smaller fluid pressure and velocity amplitudes, whereas the width (minor axis) has little effect; (4) the direction of the microcracks (major axial direction) has an limited influence area around about 1/15 of the osteon cross-sectional area.
CONCLUSIONS
This model permits the linking of the external loads and microcracks to the osteonal fluid pressure and velocity, which can be used for other purpose associate microcracks with the mechanotransduction and bone remodeling.
Topics: Elasticity; Finite Element Analysis; Haversian System; Humans; Models, Biological; Porosity; Pressure; Stress, Mechanical
PubMed: 27149885
DOI: No ID Found -
Bone May 2018Cement lines are known as thin peripheral boundaries of the osteons. With a thickness below 5 μm their composition of inorganic and organic compounds has been a...
Cement lines are known as thin peripheral boundaries of the osteons. With a thickness below 5 μm their composition of inorganic and organic compounds has been a matter of debate. Here, we hypothesized that cement lines become hypermineralized and their degree of mineralization is not constant but related to the tissue age of the osteon. Therefore, we analyzed the calcium content of osteons and their corresponding cement lines in a range of different tissue ages reflected by osteonal mineralization levels in femoral cortical bone of both postmenopausal women with osteoporosis and bisphosphonate-treated cases. Quantitative backscattered electron imaging (qBEI) showed that cement lines are hypermineralized entities with consistently higher calcium content than their corresponding osteons (mean calcium content: 29.46 ± 0.80 vs. 26.62 ± 1.11 wt%; p < 0.001). Micro-Raman spectroscopy complemented the qBEI data by showing a significantly higher phosphate/amide I ratio in the cement lines compared to the osteonal bone (8.78 ± 0.66 vs. 6.33 ± 0.58, p < 0.001), which was both due to an increased phosphate peak and a reduced amide I peak in cement lines. A clear positive correlation of cement line mineralization and the mineralization of the osteon was observed (r = 0.839, p = 0.003). However, the magnitude of the difference between cement line and osteonal calcium content decreased with increased osteonal calcium content (r = -0.709, p < 0.001), suggesting diverging mineralization dynamics in these osseous entities. The number of mineralized osteocyte lacunae per osteon bone area correlated positively with both osteonal and cement line calcium content (p < 0.01). The degree of mineralization of cement lines may represent another tissue-age related phenomenon, given that it strongly relates to the osteonal mineralization level. Understanding of the cement lines' mineralization and their changes in aging and disease states is important for predicting crack propagation pathways and fracture resistance mechanisms in human cortical bone.
Topics: Absorptiometry, Photon; Aged; Aged, 80 and over; Bone Remodeling; Bone and Bones; Female; Haversian System; Humans; Microscopy, Electron, Scanning; Osteocytes; Postoperative Period; Spectroscopy, Fourier Transform Infrared; Spectrum Analysis, Raman
PubMed: 29427789
DOI: 10.1016/j.bone.2018.02.004 -
Science (New York, N.Y.) Apr 1968Modified electron-microscopic techniques permit the sectioning of fully mineralized compact bone. Cortical canals in human femur are extensively innervated. Most nerves...
Modified electron-microscopic techniques permit the sectioning of fully mineralized compact bone. Cortical canals in human femur are extensively innervated. Most nerves are unmyelinated and range from 0.5 to 10 micrometers in diameter. I have found a few mixed nerves (myelinated and unmyelinated fibers), one of which was 130 micrometers in diameter.
Topics: Bone and Bones; Female; Femur; Haversian System; Humans; Microscopy, Electron; Middle Aged
PubMed: 5641266
DOI: 10.1126/science.160.3825.327 -
Journal of Biomechanics Oct 2003The concept of bone remodelling by basic multicellular units is well established, but how the resorbing osteoclasts find their way through the pre-existing bone matrix...
The concept of bone remodelling by basic multicellular units is well established, but how the resorbing osteoclasts find their way through the pre-existing bone matrix remains unexplained. The alignment of secondary osteons along the dominant loading direction suggests that remodelling is guided by mechanical strain. This means that adaptation (Wolff's Law) takes place throughout life at each remodelling cycle. We propose that alignment during remodelling occurs as a result of different canalicular flow patterns around cutting cone and reversal zone during loading. Low canalicular flow around the tip of the cutting cone is proposed to reduce NO production by local osteocytes thereby causing their apoptosis. In turn, osteocyte apoptosis could be the mechanism that attracts osteoclasts, leading to further excavation of bone in the direction of loading. At the transition between cutting cone and reversal zone, however, enhanced canalicular flow will stimulate osteocytes to increase NO production, which induces osteoclast retraction and detachment from the bone surface. Together, this leads to a treadmill of attaching and detaching osteoclasts in the tip and the periphery of the cutting cone, respectively, and the digging of a tunnel in the direction of loading.
Topics: Biomechanical Phenomena; Bone Matrix; Bone Remodeling; Extracellular Fluid; Haversian System; Humans; Models, Biological; Osteoclasts; Rheology; Walking; Weight-Bearing
PubMed: 14499294
DOI: 10.1016/s0021-9290(03)00126-x -
American Journal of Physical... Oct 2009The growth, development, and maintenance of bone are influenced by genetic and environmental variables. Understanding variability in bone microstructure among primates...
The growth, development, and maintenance of bone are influenced by genetic and environmental variables. Understanding variability in bone microstructure among primates may help illuminate the factors influencing the number and size of secondary osteons. The purpose of this study is to assess the bone microstructure in 8 humeral and 12 femoral sections of 12 juvenile chimpanzees, aged 2-15.3 years, and one adult chimp. Secondary osteons were counted and measured for 16 fields per section. Results indicate that the femur exhibits a mean osteon population density (OPD) of 4.46 +/- 2.34/mm(2), mean Haversian canal area of 0.0016 +/- 0.0007 mm(2), and mean osteon area of 0.033 +/- 0.006 mm(2). The humerus has a mean OPD of 4.72 +/- 1.57/mm(2), mean Haversian canal area of 0.0013 +/- 0.0003 mm(2), and mean osteon area of 0.033 +/- 0.005 mm(2). Differences are not significant between the humerus and femur, possibly indicating similar mechanical demands during locomotion. Osteon population density exhibits a moderate correlation with age (r = 0.498) in the femur of the juvenile chimps, but the adult chimp has an OPD of 10.28/mm(2), suggesting that osteons likely accumulate with age. Females exhibit higher osteon densities in the periosteal envelope compared to males in the humerus, indicating more remodeling during periosteal expansion. Overall similarities between chimpanzees and humans as well as previously published data on Late Pleistocene hominids (Abbott et al.: Am J Phys Anthropol 99 1996 585-601) suggest that bone microstructure has been stable throughout human evolution.
Topics: Animals; Bone Development; Female; Femur; Haversian System; Humerus; Image Processing, Computer-Assisted; Male; Pan troglodytes; Species Specificity
PubMed: 19434755
DOI: 10.1002/ajpa.20959 -
Journal of Biomechanics May 2011This Finite Element study aims at understanding the transverse osteon as a composite microstructure, and at differentiating the actions of each of its main components...
Microstructural mechanical study of a transverse osteon under compressive loading: The role of fiber reinforcement and explanation of some geometrical and mechanical microscopic properties.
This Finite Element study aims at understanding the transverse osteon as a composite microstructure, and at differentiating the actions of each of its main components and their interactions. Three components of the osteon have been distinguished: the lamellae mineral-collagen matrix, the lamellae mineral-collagen reinforcement fibers and the Haversian canal content made of intracortical fluid and soft tissues. Numerical compression experiments have been performed, varying the microstructure properties. Our results show that fiber reinforcement of transverse osteons is only efficient at resisting dynamic compressive loadings, but that the improvement of the static compressive properties is very poor. Furthermore, the modeled stress distribution within the matrix and reinforcement fibers may explain why transverse osteons are often limited to a small number of lamellae (<8) and why internal lamellae could be stiffer than external ones.
Topics: Biomechanical Phenomena; Collagen; Elasticity; Finite Element Analysis; Haversian System; Humans; Models, Anatomic; Models, Biological; Pressure; Stress, Mechanical
PubMed: 21397233
DOI: 10.1016/j.jbiomech.2011.02.075 -
The Journal of Surgical Research Mar 1963
Topics: Bone and Bones; Fluorescence; Half-Life; Haversian System; Humans; Microscopy; Microscopy, Fluorescence
PubMed: 13987600
DOI: 10.1016/s0022-4804(63)80035-9 -
Anatomischer Anzeiger 198425 bone cylinders from 5 human femora were examined with respect to the direction of osteons, visualizing the Haversian systems. These canal systems, infiltrated with...
25 bone cylinders from 5 human femora were examined with respect to the direction of osteons, visualizing the Haversian systems. These canal systems, infiltrated with indian ink showed characteristic patterns. The osteons of the femur shaft run from proximally anterior to distally posterior, forming a double diagonal architecture. From these results it is derived, that the architecture of osteons may be looked at as a functional adaptation to mechanical stresses in the femur diaphysis.
Topics: Aged; Biomechanical Phenomena; Female; Femur; Haversian System; Humans; Middle Aged; Osteocytes
PubMed: 6721194
DOI: No ID Found -
Journal of Bone and Mineral Metabolism Jul 2021Static cortical bone histomorphometry utilised in forensic age-at-death estimation generally examines only the anterior femoral mid-shaft, as biomechanical strain at the...
INTRODUCTION
Static cortical bone histomorphometry utilised in forensic age-at-death estimation generally examines only the anterior femoral mid-shaft, as biomechanical strain at the posterior femur is thought to result in increased bone remodelling, osteon density and adversely affect age-at-death estimates. As osteon density increases there is a corresponding decrease in geometric variables, such as osteon area and Haversian canal diameter. The present study tests whether the inverse relationship between osteon density and osteon geometry is reflected in a modern documented Australian sample, and if this relationship differs between the anterior and posterior femoral mid-shaft.
MATERIALS AND METHODS
The study sample comprises 215 femoral microradiographs (117♂ 98♀) of recorded age (18‒97 years) from the Melbourne Femur Reference Collection (MFRC). The following variables were measured in Image J across six 1 mm regions of interest (ROIs) from the anterior and posterior; mean intact and fragmentary secondary osteon count, osteon population density, osteon and Haversian canal area, perimeter, and diameter.
RESULTS
Osteon area was positively correlated with Haversian canal size and shape metrics, and negatively correlated with osteon density. Chronological age was significantly correlated with most variables. There were significant between-group effects between the youngest (18‒34 years) and all other age groups (35‒49, 50-74 and 75 + years) for both regions.
CONCLUSION
Our findings support an increased rate of remodelling associated with decreases in osteon geometry in the anterior and posterior femur. Future studies should examine static osteon histomorphometry using anterior and posterior measurements in larger samples of documented age and sex.
Topics: Adolescent; Adult; Aged; Aged, 80 and over; Biomechanical Phenomena; Femur; Haversian System; Humans; Male; Middle Aged; Observer Variation; Young Adult
PubMed: 33725170
DOI: 10.1007/s00774-021-01204-7 -
Medicine, Science, and the Law Jan 2024Numerous age estimation methods in unidentified bone have been a long time developing for application in forensic anthropology. The histomorphometric technique is one of... (Review)
Review
Numerous age estimation methods in unidentified bone have been a long time developing for application in forensic anthropology. The histomorphometric technique is one of the alternative methods that relied upon the evaluation of the cortical bone microstructure over the lifespan as a result of the remodeling process in bone. Remodeling is a sophisticated event occurring from the coupled function of bone formation and resorption cells for maintaining mineral homeostasis and repairment of microdamage in bone tissue. Products derived from remodeling are primary changes in the osteon or haversian system in various regions in the cortical bone, including periosteum, endosteum, and trabecular bone. Throughout life, bone remodeling rate with osteon alteration can be predictable. In the forensic field, histological methods are getting more attention due to the unavailability of macroscopic methods. Histomorphometry approach can be accomplished in fragmentary or incomplete bone remains indicating the limited use of gross morphological methods. In addition, the microscopic methods can aid to increase the more accuracy of analyses and diminish the biased subjective assessment for determining age. Most histomorphometry method utilizes a cross-section of the midshaft of the long bones including the mandible, rib, and clavicle. This review provides the basic knowledge of bone biology and anatomy, several age-estimating methods of histology, and crucial factors for age methods. Studies regarding overall age determination methods from the past until now contribute to obtaining more benefits for developing methods of histomorphometry using human bone in forensic identification.
Topics: Humans; Ribs; Bone Remodeling; Haversian System; Longevity; Osteogenesis
PubMed: 37876174
DOI: 10.1177/00258024231208280