China
Africa
Explore chapters and articles related to this topic
Designing for Head and Neck Anatomy
Published in Karen L. LaBat, Karen S. Ryan, Human Body, 2019
The lower portion of the face, the jaw, provides protection as well as the motion essential for chewing and talking. The maxillae are the paired stationary upper jawbones which you can feel as a U-shaped structure holding your upper teeth. Each maxilla reaches all the way to the lower border of the eye and abuts the nasal bones medially and the zygomatic bone laterally. The mandible (lower jawbone), also U-shaped, is separate from the skull and holds the lower teeth. The temporomandibular joint (TMJ), the articulation between mandible and temporal bone, just in front of the ear canal, allows movement of the lower jaw so that you can talk and chew (inset, Figure 3.3). Keep the movement of the lower jaw (up, down, forward and back, and side-to-side) in mind when designing headgear that is strapped under the chin and/or worn while eating or talking.
Discrete Reduced Interference Distributions
Published in Antonia Papandreou-Suppappola, Applications in Time-Frequency Signal Processing, 2018
Many people have experienced the popping or clicking of a joint. Sometimes the temporomandibular joint (TMJ) clicks or pops when the jaw is moved. In many cases, this is a rare and harmless event. However, it may be indicative of a potentially serious condition. Such activity may be associated with a great deal of pain, perhaps even triggering headaches or other distressing symptoms. Even if one does not experience pain, these joint sounds may herald the development of more serious conditions. There is almost always someone in the audience with personal knowledge of pain and suffering from these problems, in terms of themselves, friends or family members when TF results are presented on these TMJ sounds. Previous work aimed at analyzing these signals has been spotty and mixed in results. Usually, the clinician simply listens to the sound and tries to report the results in some objective way. However, this method is highly subjective and often couched in terms such as likening the sound to “a dry stick breaking” or “the crunching of dry snow.” Arthritic joints, in particular, often produce creaking or crunching sounds. This is often called crepitation.
Finite element analysis in design of DMLS mandible implants
Published in Fernando Moreira da Silva, Helena Bártolo, Paulo Bártolo, Rita Almendra, Filipa Roseta, Henrique Amorim Almeida, Ana Cristina Lemos, Challenges for Technology Innovation: An Agenda for the Future, 2017
T.C. Dzogbewu, L. Monaheng, I. Yadroitsava, W.B. du Preez, I. Yadroitsev
The human mandible (lower jaw) is noted as the strongest bone of the skull and is capable of moving independently from the head movement. It supports the lower teeth and provides a place of attachment for the mastication muscles (Saladin 1998). The masseter muscle is the principal mastication muscle and is responsible for retracting and elevating the mouth (opening and closing of the mouth). It must be able to exert enough force for biting and chewing of food (Santana-Mora et al. 2014). The magnitude of the resultant force produced by the mastication muscles on the dental arches during clenching of the teeth in maximum intercuspation for normal humans ranges from 246.9 to 2091.9 N (Hattori et al. 2009). The resultant force during clenching of the teeth was found to act at an angle of approximately 69° to the occlusal plane. This is because the angle between the occlusal plane and the anterior boarder of the masseter muscle remains approximately 69° (Figure 2b, point D) based on the cephalogram analysis of Sato et al. (2007).
Morphological analysis of the temporomandibular joint in patients with anterior disc displacement
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2023
Tinghui Sun, Bingmei Shao, Desmond Y. R. Chong, Zhan Liu
Temporomandibular disorders (TMD) are the most common issues when it comes to our jaw joints, sensitive bi-condylar joints that connect the mandible to the skull and regulate jaw movements during mastication, speech, expression, etc. There is a high prevalence of TMD in adults and the symptoms vary from mild discomfort to painful temporomandibular joint (TMJ) dysfunction. It was reported that 25% to 30% of the population has at least one TMD symptom (Solberg et al. 1979; Rugh and Solberg 1985; Koh and Robinson 2004) and the overall prevalence of TMD in females was much higher than in males with ratios varying from 2:1 to 8:1 in the different surveys (Solberg et al. 1979; Ingawale and Goswami 2009; de Godoi Gonçalves et al. 2010; Martins-Junior et al. 2010). Despite the high incidence of TMD, only a small amount of the patients would seek medical help, for the symptoms are mild at the early stage and many of them can be relieved spontaneously.