Anatomy and Embryology of the Mouth and Dentition
John C Watkinson, Raymond W Clarke, Terry M Jones, Vinidh Paleri, Nicholas White, Tim Woolford in Head & Neck Surgery Plastic Surgery, 2018
The articular disc (meniscus) is of a dense, fibrous consistency and is moulded to the bony joint surfaces above and below. Blood vessels are only evident at the periphery of the articular disc, the bulk of its central part being avascular. When viewed in sagittal section, the upper surface of the disc is concavo-convex anteroposteriorly and the lower surface is concave. Viewed superiorly, the articular disc is somewhat rectangular or oval in outline. The overall shape of the articular disc is thought to provide a self-centring mechanism, which automatically acts to maintain its correct relationship to the articular surface of the mandibular condyle during mandibular movements. Whereas some regard the functions of the articular disc as helping to spread the joint forces and to stabilize the condyle, others see its function as primarily destabilizing the condyle and permitting it to move more freely.16
Radius and ulnar shaft
Sebastian Dawson-Bowling, Pramod Achan, Timothy Briggs, Manoj Ramachandran, Stephen Key, Daud Chou in Orthopaedic Trauma, 2014
The DRUJ is a uniaxial synovial pivot joint. The triangular fibrocartilage complex (TFCC) contributes significantly to DRUJ stability and comprises: Articular disc of triangular fibrocartilage.Ulnar collateral ligaments.Meniscal homologue.Volar, dorsal radiocarpal ligaments.Extensor carpi ulnaris sheath.Dorsal and volar radioulnar ligaments.
Effects of introducing gap constraints in the masticatory system: A finite element study
J. Belinha, R.M. Natal Jorge, J.C. Reis Campos, Mário A.P. Vaz, João Manuel, R.S. Tavares in Biodental Engineering V, 2019
The temporomandibular joint (TMJ) is a synovial joint which articulates the jaw to the skull. It is composed principally by the mandibular condyle, the mandibular fossa, the articular disc, the capsule, the ligaments and the lateral pterygoid muscle. The articulating surfaces of the condyles and the mandibular fossa are covered with articular cartilage, which together with the synovial fluid allows for a very low coefficient of friction and a uniform transmission of compressive forces to the bone (Radin et al. 1971). The articular cartilage of the TMJ contains both collagen fibers type I and type II, which classifies it as fibrocartilage. Due to the low permeability of the tissue, compression forces rapidly increase fluid pressure, which in turn carries the major part of the load through hydrostatic pressurization (Mow et al. 2005). The collagen fibers of the cartilage, on the other hand, resist the stretching of the tissue from tensile forces (Hukins et al. 1984). The articular disc, also composed of fibrocartilage, lies between the mandibular condyle and the fossa, dividing the synovial joint in two. It distributes loads and dissipates the energy caused from impact loads. The disc allows for relative motion between the condyle and the temporal bone. In the case of the condyle, both translational and rotational motions are possible. The articular disc is connected to the articular surfaces through the joint capsule. The attachments of the joint capsule can be divided as shown in Figures 1–2 into medial, lateral, anterior and posterior attachments. These attachments give the disc a range of movement and at the same time avoid extreme displacements that may result in the dislocation of the disc.
Effect of sagittal split ramus osteotomy on stress distribution of temporomandibular joints in patients with mandibular prognathism under symmetric occlusions
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2020
Hedi Ma, Jingheng Shu, Quanyi Wang, Haidong Teng, Zhan Liu
In this study, the surface-to-surface contact discretization method and the small-sliding tracking approach were used. For the tangential behavior, the penalty function was chosen as the friction formulation based on previous studies, and the frictional coefficient of the contact area was considered to be 0.001 ( Liu et al. 2008; Shu et al. 2018). For the normal behavior, the Lagrange multiplier method was chosen as constraint enforcement method (Liu et al. 2008; Shu et al. 2018). Young moduli of the bones (cortical bone, cancellous bone, and teeth) were assigned according to the empirical formulas given in Equations (1)–(3) (Harp et al. 1994; Rho et al. 1995; Kopperdahl et al. 2002). The material properties of the articular disc were assumed to be linearly elastic (Liu et al. 2008). Young moduli of the articular disc was defined as 44.1 MPa (Liu et al. 2008). Poisson ratios of the bones (cortical bone, cancellous bone, and teeth) and the disc were defined as 0.3 and 0.4, respectively (Liu et al. 2008). The modified ten-node quadratic tetrahedron element (C3D10M) was used in the TMJ regions and the four-node linear tetrahedron element (C3D4) was used in the other regions of the models. The average number of nodes and elements for the finite element models were about 30,550 and 87,200 through convergence test. The mesh quality of all the models was checked in ABAQUS. The analysis error of mesh was 0, and the analysis warning of mesh was under 5%.
Temporomandibular Disorder: An Important Cause of Temporal Headache in Patients Unlikely to Have Giant Cell Arteritis
Published in Seminars in Ophthalmology, 2019
Kerr Brogan, David Lockington, Kanna Ramaesh
TMD is a complex and multifactorial condition with prevalence ranging between 5% and 70% in different populations.9,10 There are three different processes that lead to pain in TMD: arthritic changes causing degeneration of articulating surfaces; internal derangement of the joint (commonly abnormal position of the intra-articular disc); and increased muscle tension and spasm around the joint.11 The latter is associated with psychological stress. All of these mechanisms can result in jaw pain when eating (thus mimicking jaw claudication as seen in GCA). The TMJ is innervated by the mandibular division of the trigeminal nerve. Irritation of this nerve in TMD not only causes localised pain at the TMJ but can also cause referred pain throughout the corresponding trigeminal sensory distribution; this innervation includes the side of the head and scalp.5 Consequently, patients with TMD can experience a temporal headache which, again, may lead to suspicion of GCA.
Preliminary simulation model toward the study of the effects caused by different mandibular advancement devices in OSAS treatment
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2018
Agnese Brunzini, Antonio Gracco, Alida Mazzoli, Marco Mandolini, Steve Manieri, Michele Germani
Next steps focus on the TMJ modelling. Soft tissues such as articular disc and ligaments are not identifiable from CT images. For this reason, the reconstructed surfaces of temporal bone, mandible and teeth are imported in Rhinoceros 3D v.5.0 by McNeel Inc., a commercial 3D modelling tool, where soft elements are designed according to anatomical atlas and medical literature. The articular disc has been modelled following the method proposed by Alkhiary et al. 2012, extracting the upper surface of the condyle toward the glenoid fossa. The result is shown in Figure 1.
Related Knowledge Centers
- Fibrocartilage
- Meniscus
- Joint
- Triangular Fibrocartilage
- Articular Disk of The Temporomandibular Joint
- Articular Disc of Sternoclavicular Joint