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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.
Bone Microcirculation
Published in John H. Barker, Gary L. Anderson, Michael D. Menger, Clinically Applied Microcirculation Research, 2019
Kelly54 has estimated the capacity of veins draining bone to be six to eight times that of inflow arteries. Most of the drainage in long bone occurs at the epiphysis.54 In general, venous output from the epiphysis and metaphysis is concomitant with arterial pathways. However, there are more arteries than veins in these networks.70 The central sinus is assumed to empty into nutrient veins. Only about 10% of the venous drainage is through the nutrient veins, however, according to canine studies.106 Blood not exiting these pathways follows the emissary veins, which collect from sinusoids and haversian vessels and course through enlarged Volkmann’s canals to anastomose with periosteal and/or soft tissue veins.106 Two separate efflux tributaries have been hypothesized by Oni,71 who envisioned parallel efflux systems, one carrying blood to the haversian, emissary, and systemic vessels from nutrient arteries and sinusoids and the other the venous sinus to the nutrient veins (which are concomitant with the nutrient arteries).
Basics of Bone
Published in Manoj Ramachandran, Tom Nunn, Basic Orthopaedic Sciences, 2018
Peter Bates, Bjarne Moller-Madsen, Ali Noorani, Manoj Ramachandran
A second system of canals called Volkmann’s canals penetrates and runs perpendicular to the long bone axis, connecting the inner and outer surfaces of the bone. These canals carry blood vessels to and from the Haversian systems. At the periosteal and endosteal surfaces, lamellae run parallel to the surface, forming circumferential and endosteal lamellae.
OCT Imaging in Infants
Published in Seminars in Ophthalmology, 2022
Sushma Jayanna, Subhadra Jalali, Tapas R Padhi, Komal Agarwal, Jay Chhablani
Choroidal osteoma is a benign tumor, commonly seen in females, has been reported as early as in a 4-week-old baby.40 Tumor is slow growing bilateral, well-defined orange mass involving posterior pole. Loss of vision occurs because of complications like choroidal neovascular membrane (CNVM), decalcification of tumor and RPE atrophy in later stages. OCT shows homogeneous localized hypo reflective mass at the choroid pushing overlying retinal layers. Other reported findings on OCT include subtle horizontal hyper-reflective lamellar lines, speckled-spongy tissue, and horizontally or vertically oriented tubular channels representing Volkmann canals, which correlate with mature bone histology.41,42
Parameter identification for the simulation of the periodontal ligament during the initial phase of orthodontic tooth movement
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2021
Albert Heinrich Kaiser, Ludger Keilig, Reinhard Klein, Christoph Bourauel
The periodontium is a compound of several tissues that support the teeth. It includes the gingiva, the cementum, the periodontal ligament and the alveolar bone proper. According to Hand and Frank (2015), ‘The periodontal ligament attaches the tooth root to alveolar bone, and it serves to absorb and resist the forces of occlusion on the tooth. It consists of collagenous fiber bundles… Interstitial areas containing loose connective tissue, blood vessels, and nerves are present between the fiber bundles in the periodontal ligament. These interstitial areas are continuous with openings through the alveolar bone (Volkmann’s canals) to the marrow spaces of the alveolar process.’