Facial anatomy
Michael Parker, Charlie James in Fundamentals for Cosmetic Practice, 2022
The mandible is the jawbone (Figure 3.6), and it articulates with the temporal bone at the temporomandibular joint, allowing us to open and close the mouth at our leisure. It is found directly inferior to the maxilla and offers a point of anchorage of our lower teeth. The mandible is a complex bone with multiple discernible anatomical segments, including the body, angle, ramus, condyle and coronoid process. The area at which the two halves of the mandible fuse during development is known as the symphysis menti, located in the midline of the chin. The mandible has two main foramina on each side, the mandibular and mental foramina. The mandibular foramina are located in the middle of each mandibular ramus, and the mental foramina are located just lateral to the chin bilaterally. The mental foramina are of key clinical significance regarding augmentation of the chin with dermal fillers, as with any other facial foramina, due to the risk of avascular necrosis, filler embolisation and neuronal damage of structures exiting them.
The Digestive (Gastrointestinal) System and Its Disorders
Walter F. Stanaszek, Mary J. Stanaszek, Robert J. Holt, Steven Strauss in Understanding Medical Terms, 2020
The periodontium consists of the tissues that surround and support the teeth, which are the gingiva, periodontal ligament, cementum, and alveolar bone. The gingiva is the part of the oral mucosa that covers the alveolar process of the jaw and surrounds the neck of the tooth. Periodontal ligaments serve to attach teeth to the bone; to maintain gingival tissues in the proper relationship to teeth, as shock absorbers; and to provide a casing to protect the vessels and nerves. Cementum is the calcified or hardened tissue that forms the outer covering of the anatomic root. The process of its formation is variable, but continuous. The alveolar bone or tooth socket is the socket in the maxilla (upper jawbone) or mandible (lower jawbone) into which each tooth fits.
Musculoskeletal system
A Stewart Whitley, Jan Dodgeon, Angela Meadows, Jane Cullingworth, Ken Holmes, Marcus Jackson, Graham Hoadley, Randeep Kumar Kulshrestha in Clark’s Procedures in Diagnostic Imaging: A System-Based Approach, 2020
The temporomandibular joint (TMJ) is a synovial condyloid joint formed between the head (condyle) of the mandible and the mandibular fossa of the temporal bone (Fig. 3.50). The anterior part of the mandibular fossa, with which the head of the mandible articulates when the mouth is opened, is termed the articular tubercle. The joint capsule is attached superiorly to the rim of the articular surface and inferiorly to the neck of the mandible. The capsule is strengthened laterally to form the lateral or temporomandibular ligament. Intrinsically there is an interarticular disc (meniscus) that divides the joint into the superior and inferior cavities. It is attached to the periphery of the capsule and is situated over the head of the mandible, projecting anteriorly towards the tubercle. A number of small muscles combine to produce depression, elevation, protrusion, retraction and lateral movements of the mandible. These movements are complex, and the action of opening the mouth results in the head of the mandible moving downwards and forwards. Excessive movement can result in anterior dislocation of the head of the mandible on the articular tubercle. The joint derives its blood supply from the temporal and maxillary branches of the external carotid artery.
An approach for simultaneous reduction and fixation of mandibular fractures
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2023
Ethan Snyder, Mohamed Trabia, Nir Trabelsi
Bones are composed of an outer cortical bone shell surrounding a cancellous bone interior. The cortical bone shell has a higher density, providing most of the structural stiffness and load bearing for bones, while cancellous bone ensures that the load is evenly distributed (Ott 2018). The mandible tends to be an anomaly in respect to other bones. It has a relatively irregular shape with cavities along the top surface for teeth. Additionally, the thickness of the cortical shell of the mandible varies across its contour of the bone, with an average thickness of approximately 2.5 mm (Batbayar et al. 2019). Modeling mandibular cortical and cancellous bone as a linearly elastic, homogeneous and isotropic material is fairly common, e.g. (Lovald et al. 2010), (Kılınç et al. 2018) since they are easy to implement. However, these models do not accurately represent mandibular bones, whose properties were experimentally found to be a function of direction and location, (van Eijden 2000). Several researchers have used orthotropic material models, e.g. (Kharmanda et al. 2020). However, it may be difficult to use these models accurately due to the irregularity of the mandible.
Finite element analysis of biplanar customized reconstruction plates for lateral and central segmental defects of mandible
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2023
Esin Demir, Gökhan Yalçın, Abdullah Kalaycı
Nine models were evaluated under right unilateral molar clenching. Displacements at the top of both condyles were restricted in all directions. Displacement in the vertical direction was restricted on the right molars to simulate unilateral chewing (Figure 3). Chewing was simulated by applying forces corresponding to the masticatory muscles that were adhered to mandible. The following six principal muscles were evaluated for each model: the superficial masseter (SM), deep masseter (DM), medial pterigoid (MP), anterior temporalis (AT), middle temporalis (MT) and posterior temporalis (PT). Values and directions of masticatory forces were based on similar studies and illustrated in Figure 4 and Table 3 (Korioth et al. 1992; Kimura et al. 2006; Narra et al. 2014; Park et al. 2018).
Peripheral intraosseous carcinoma arising from a recurrent odontogenic keratocyst
Published in Baylor University Medical Center Proceedings, 2023
Isherpreet Shergill, Thomas Schlieve, Fayette Williams, Roderick Kim, Daniel Hammer
PIOC is a rare carcinoma that arises from the direct transformation of odontogenic epithelial rests in the jaw. The carcinogenic process is similar in PIOC and oral squamous cell carcinoma, but the tumors exhibit different oncogenes and tumor markers, indicating different genetic pathways.2 The incidence has been estimated at 0.3% to 3%.3 PIOC has a predilection for the mandible (79%) compared to the maxilla (21%). In the mandible, the posterior region is most commonly involved, while in the maxilla, the anterior region is affected.3 Clinical features such as pain, sensory disturbances without history of trauma, swelling, perforation of buccal and lingual cortical plates, adherence of the cyst lining to the bony cavity, and chronic sinus tracts are common findings.4 Malignant transformation of the odontogenic cyst epithelium due to long-standing chronic inflammation might be the main predisposing factors.5,6 Persistent infections associated with odontogenic cysts should encourage the surgeon to consider the possibility of an underlying malignancy.7
Related Knowledge Centers
- Alveolar Process
- Bone
- Maxilla
- Mouth
- Skull
- Temporal Bone
- Jaw
- Temporomandibular Joint
- Tooth
- Nerve