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Mechanical testing
Published in C M Langton, C F Njeh, The Physical Measurement of Bone, 2016
Christopher F Njeh, Patrick H Nicholson, Jae-Young Rho
Anatomically, two forms of bone are distinguishable: the cortical (compact) and trabecular (spongy or cancellous) bone. Cortical bone appears as a solid continuous mass in which spaces can be seen only with the aid of a microscope. Cancellous bone on the other hand consists of a three-dimensional network of trabeculae, with the interspaces occupied by bone marrow. Both cortical and cancellous bones have a very similar basic composition, although the true density of fully calcified cancellous bone is a little lower (3%), and its proteoglycan content a little greater than those of the fully calcified compact bone. Although still contentious, the real difference between compact and cancellous bone depends on its porosity: that of compact bone, mainly due to the voids provided by osteon canals, Volkmann’s canals, osteocytes and their canaliculi and resorption lacunae, varies from 5 to 30% (apparent density about 1.8 g/cm3); the porosity of cancellous bone, chiefly due to the wide vascular and bone marrow intertrabecular spaces, ranges from 30 to more than 90% (apparent density 0.1 to 0.9 g/cm3) [2]. It has also been argued that since cancellous bone is more metabolically active compared with cortical bone, this could create newer and more mechanically competent bone [3]. Trabeculae are the unit components of the cancellous bone.
Tissue Biomechanics
Published in Ronald L. Huston, Principles of Biomechanics, 2008
As the bones are loaded (primarily in compression) the trabeculae align themselves and develop along the stress vector directions, in accordance with Wolff’s law [2]. Intuitively, the rate and extent of this alignment (through modeling and remodeling) is proportional to the rate and extent of the loading. Specifically, high intensity loading, albeit only for a short duration, is more determinative of bone remodeling than less intensive longer lasting loading [10]. Weightlifters are thus more likely to have stronger, higher mineral density bones than light exercise buffs (walkers, swimmers, and recreational bikers).
In Vivo Bone Imaging with Micro-Computed Tomography
Published in de Azevedo-Marques Paulo Mazzoncini, Mencattini Arianna, Salmeri Marcello, Rangayyan Rangaraj M., Medical Image Analysis and Informatics: Computer-Aided Diagnosis and Therapy, 2018
Steven K. Boyd, Pierre-Yves Lagacé
Mechanical properties of trabecular bone are influenced by three main factors: apparent density (bone volume fraction), microarchitecture and mineral-collagen ratio (Goulet et al. 1994; Gibson 1985; Carter and Hayes 1976; Carter et al. 1980; Carter and Hayes 1977; Hodgskinson et al. 1989; Van Der Linden et al. 2001). The number, thickness and arrangement of the trabeculae are especially important as determinants of trabecular bone strength (Seeman 1999).
Relating mechanical properties of vertebral trabecular bones to osteoporosis
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2020
R. Cesar, J. Bravo-Castillero, R. R. Ramos, C. A. M. Pereira, H. Zanin, J. M. D. A. Rollo
Trabecular bone, the focus of our research, is metabolically more active than cortical bone and has a high surface area exposed to the bone marrow and blood flow, unorganized collagen fibers and lamellar structure without a Haversian system (Parfitt 2002; Fairfield et al. 2019; Singhal and Bredella 2019). It is found in large quantities in the calcaneus, femoral neck, vertebral body (Osterhoff et al. 2016; Syahrom et al. 2017). Depending on the requested load and anatomical region, it presents good mechanical properties due to its 3 D complex hierarchical network (honeycomb-like) and irregular structural organization, which helps to absorb the energy of impacts and distribute multidirectional loads, which is crucial to the enabling of body movement (Novitskaya et al. 2011; Lopes et al. 2018). It exists in four basic forms: i) asymmetric, open cell; rod-like structure; ii) columnar, open cell, rod-like structure; iii) asymmetric, closed cell, plate-like structure and iv) columnar, closed cell, plate-like structure (Dempster et al. 2013; Wang et al. 2015; Choi and Ben-Nissan 2018). Bone can be classified as composite, viscoelastic, heterogeneous, orthotropic, anisotropic material and open porous cellular solid (Keaveny et al. 2001; Lloyd et al. 2015; Nazemi et al. 2016; Burr 2019), with high porosity between 87 to 96% (Weatherholt et al. 2012; Cesar et al. 2013). The understanding of trabecular bone as spongy structure and engineering material (composite and porous), allows for an analysis of the physical, chemical, mechanical and structural properties of this biological tissue (Chappard et al. 2011; Zhou et al. 2014; Martin et al. 2015).