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Published in Bobby Krishnachetty, Abdul Syed, Harriet Scott, Applied Anatomy for the FRCA, 2020
Bobby Krishnachetty, Abdul Syed, Harriet Scott
The epiphysis of long bones is the typical insertion site for IO access. The three main layers are Periosteum – the outermost layer that surrounds the bone.Cortical bone – the middle layer, which is heavily mineralised and contains a network of blood vessels. The Haversian canals are vertical channels for blood vessels and nerves found on the outermost region of cortical bone and are connected by horizontal Volkmann canals. Concentric layers (lamellae) containing osteophytes surround the Haversian canals and interconnections between the channels and osteophytes are called canaliculi.Cancellous bone – the innermost layer and consists of multiple trabeculae in a lattice-like structure. The space between the trabeculae contains blood vessels and bone marrow. With correct placement, the tip of the IO needle lies within the cancellous bone.
Introduction
Published in Stanton H. Cohn, Non-Invasive Measurements of Bone Mass and Their Clinical Application, 2020
The reduction in bone mass, the essential feature of osteoporosis, results from an imbalance between the rate of formation of bone and the rate of resorption. Data on the change in bone mass alone cannot provide information on which parameter is responsible for the net loss of bone. Further, the reduction in bone mass appears in the trabecular bone as a loss of trabeculae, resulting in a reduction in thickness. In compact bone, there is a widening of the Haversian canals, beginning on the endosteal surface and extending outward. The phenomenon leads to canalization and a gradual narrowing of the cortex as discussed in Chapter 2. Cortical and trabecular bone can be distinguished by non-invasive bone measurement (Chapter 6); the data obtained are very useful for an understanding of the underlying mechanisms of the changing bone dynamics.
Bone and Cartilage
Published in George W. Casarett, Radiation Histopathology: Volume II, 2019
The internal structure of compact bone differs from that of spongy bone in the development of haversian systems (osteons) as the structural units of compact bone (Figure 1D). The osteons are oriented chiefly to the long axis of the bone. The axis of an haversian system is the haversian canal (generally from 22 to 110 um in diameter), which contains within its loose connective tissue one or more blood vessels (mostly capillaries and postcapillary venules, occasionally an arteriole), lymphatics, and nerves. Each haversian canal is surrounded by from 4 to 20 concentrically arranged lamellae. Each osteon contains large numbers of osteocytes in their individual lacunae, and the extravascular canaliculi radiating from the canal and interconnecting with the lacunae and other canaliculi of the osteon. Tissue fluids diffuse between the vessels in the canal and the osteocytic and lamellar surfaces through these canaliculi. Haversian canals often open into the marrow cavity.
Simulation study on the effect of resistance exercise on the hydrodynamic microenvironment of osteocytes in microgravity
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2022
Hai-Ying Liu, Chao-Hui Zhao, Hao Zhang, Wei Wang, Qing-Jian Liu
Bone is typically comprised of dense bone, cancellous bone, and tissue fluid. The osteon is the basic structural and physiological unit of dense bone, and it also has the highest bone density in the human skeletal system (Liu et al. 2020; Larcher and Scheiner 2021). The central tubular area of the osteon is called the Haversian canal, which contains arterial and venous capillaries that permit the transport of nutrients and metabolic waste needed for cell metabolism. The multi-layer circumferential lamellae around the Haversian canal consist of a complicated lacunar-canalicular system (LCS). The osteocytes are located in bone lacunae, and the adjacent osteocytes form a complex spatial mechanical signal transduction network through synaptic connections in the canaliculi. The LCS is an important channel for material exchange between osteocytes and capillaries in the Haversian canal (Kwon et al. 2010). The deformation of the bone matrix under loading can induce liquid flow in the LCS, and the mechanical signals produced by the liquid flow are perceived and responded to by osteocytes, thus regulating the activity of osteoblasts and osteoclasts to adjust bone mineral density to adapt to the current mechanical environment (Tovar et al. 2004).
Effects of irradiation in the mandibular bone loaded with dental implants. An experimental study with a canine model
Published in Ultrastructural Pathology, 2021
Sridhar Reddy Padala, Pekka Asikainen, Timo Ruotsalainen, Jopi JW Mikkonen, Tuomo S Silvast, Arto P. Koistinen, Engelbert A.J.M. Schulten, Chris M. Ten Bruggenkate, Arja M. Kullaa
Haversian canals (HCs) were evident on both buccal and lingual sites of the alveolar bone with less number in the lingual site. Although there was no statistically significant difference in the quantity of HC, irradiated bone showed a decrease in HC quantity compared to the control site. A significant difference in the diameter of HC is exhibited between irradiated (Buccal – 33.04 ± 2.8 µm, Lingual- 27.30 ± 3.1 µm) and non-irradiated sites (Buccal – 43.08 ± 4.5 µm, Lingual- 34.13 ± 4.5 µm) displaying a mean diameter smaller in the non-irradiated sites. The number of lamellar veins is decreased on the irradiated buccal site compared to the control buccal site, which is significant (p < .05). The density of subperiosteal veins exhibited no significant changes but was increased on the lingual site compared to the buccal site of the irradiated mandible.
Alveolar bone remodeling after tooth extraction in irradiated mandible: An experimental study with canine model
Published in Ultrastructural Pathology, 2018
Venni Heinonen, Timo J. Ruotsalainen, Lauri Paavola, Jopi J. Mikkonen, Pekka Asikainen, Arto P. Koistinen, Arja M. Kullaa
There were significant changes in Haversian canal diameters between the irradiated and non-radiated sides of the mandible. A previous study 23 indicates that Haversian canals grow in width after irradiation for approximately 4 weeks’ time, but on the later stages the amount of blood vessels decrease and they become obstructed. The capillaries on the other hand seem to expand based on this study. Moreover, there have been findings that indicate that the bone porosity increases surrounding the blood vessels because of the resorption. Enlarged Haversian canals may reveal active bone turnover.24