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Anatomy and Embryology of the Mouth and Dentition
Published in John C Watkinson, Raymond W Clarke, Terry M Jones, Vinidh Paleri, Nicholas White, Tim Woolford, Head & Neck Surgery Plastic Surgery, 2018
Considerable research has been undertaken on the activity of the lateral pterygoid muscle as it is believed by some that impaired activity of the muscle might predispose the joint to developing a pathology. It was originally thought that the two heads of the lateral pterygoid were reciprocal during opening and closing, the inferior head being active in opening the jaw, the superior head during closure, this view has now changed. The superior head has now been demonstrated to be active during opening and the two heads must be considered as acting together as one muscle with functional heterogeneity and with varying amounts of evenly graded activity throughout its range.19
Muscles, Blood Vessels, and Craniofacial Growth: Some Experimental Approaches
Published in D. Dixon Andrew, A.N. Hoyte David, Ronning Olli, Fundamentals of Craniofacial Growth, 2017
Carnivores have a hinge-like jaw action. The formation of a catching, crushing, and shearing apparatus results in such strong intercuspation of the teeth that no lateral movement is permitted. No actual chewing takes place as food is gulped down in large pieces. The main task of the carnivores’ masticatory apparatus is to catch the prey, then to kill it by slicing into it or breaking its bones. The most developed of the masticatory muscles is the temporalis, which extends far to the back of the skull. The masseter muscle is smaller, its deeper layer deriving from the articular disk, diverting some of the masticatory stress to the temporomandibular joint. The medial pterygoid muscle is smaller than the other muscles and the lateral pterygoid muscle is poorly developed, if present at all.
Neck
Published in Harold Ellis, Adrian Kendal Dixon, Bari M. Logan, David J. Bowden, Human Sectional Anatomy, 2017
Harold Ellis, Adrian Kendal Dixon, Bari M. Logan, David J. Bowden
Note that the lateral pterygoid muscle (48) inserts not only into a depression on the front of the neck of the mandible but also into the articular capsule of the temporomandibular joint (46) and its articular disc.
A Prospective, Randomized Clinical Trial to Evaluate Analgesic Efficacy of Bilateral Pterygopalatine Fossa Injection in Patients Undergoing Maxillofacial Cancer Surgeries Under General Anesthesia
Published in Egyptian Journal of Anaesthesia, 2021
Ekramy M Abdelghafar, Dina Nabil Abbas, Ahmed Othman, Sherif Bahaa Elddin Zayed, Ashraf Hamed Shawki
Before induction of general anesthesia, starting from the side of the tumor, the patients were placed in a lateral decubitus position to perform the block with the aid of ultrasonography (Sonosite, M-Turbo, USA). Using aseptic precautions, the linear transducer probe was positioned longitudinally on the lateral side of the face below the zygomatic bone, above the mandibular notch, and in front of the mandibular condyle with a cephalad angulation. The maxilla, lateral pterygoid plate, and lateral pterygoid muscle were identified. The surrounding vasculature, including the maxillary artery, was visualized by using Color Power Doppler in the pterygopalatine fossa. In order to optimize the “angle of insonation” (needle to probe angle), the transducer probe was placed closer (just anterior) to the mandibular condyle.
Clinical outcomes and functional recovery after temporomandibular joint replacement: a six-month follow-up study
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2020
E. Sapin-de Brosses, A.-S Bonnet, N. Zwetyenga
Temporomandibular joint replacement (TMJR) is recognized to solve pain and functional limitations when other less invasive strategies failed. TMJR consists in condyle osteotomy (leading to the section of the lateral pterygoid muscle) followed by the fixation of the fossa and the mandibular components. The surgery leads to immediate pain relief and a progressive increase of the mouth opening, assessed by the gap between the upper and lower incisal teeth. Other parameters were rarely considered such as the trajectories of mandibular landmarks (Wojczyńska et al. 2019). Our study combines the assessment of the quality of life (QoL) outcomes with quantitative functional measurements – electromyography (EMG) of the masticatory muscles and 3 D mandibular motions – in order to evaluate the mid-term effects of TMJR.
Analysis of temporomandibular joint dysfunction in paediatric patients with unilateral crossbite using automatically generated finite element models
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2020
Javier Ortún-Terrazas, José Cegoñino, Edson Illipronti-Filho, Amaya Pérez del Palomar
The differences between 2D and 3D approaches were evaluated for 4 paediatric patients because 2D models assume a more simplified geometry than 3D models generated using CT or CBCT images. The results (Figure 5c) revealed marked similarity between both approaches, with a mean relative error of 13%. Among other factors, this deviation may be due to the geometric simplification of the condylar head’ shape or not considering the occlusion’s role in the condyle’s placement in the 2D model. For instance, during working movement, the occlusion’s effect was not considered since the initial position of our models is already occluded and therefore, the condyles’ upward movement is mainly induced by the masseter muscles’ activities. At the same time, we consider that occlusal contacts on the balancing side hardly have any impact on the joint movement of this side, whose anterior movement is mainly guided by the temporal eminence and promoted by the action of the lateral pterygoid muscle. Biomechanically, the positive absolute error values (Appendix B, Table B1, supplementary material) suggest that during both working and balancing activity the solid phase of the TMJ disc is less loaded in the 2D than the 3D approach. The low load state of the solid phase in the 2D approach may be due to the differing degrees of freedoms between the two models. In the 3D approach, the fluid can flow in all directions, while in the 2D approach the fluid cannot drain perpendicular to the plane of the 2D model. This may explain the less compressible response of the TMJ disc in the 2D simulations (Figure 5c), and the resulting decrease in the stress supported by the solid phase.