The mandible is the largest of the facial bones, occupying a prominent position upon and providing the foundation for the lower third of the face. Despite holding the honour of being the strongest bone in the face, its protrusive location makes it vulnerable to injury – particularly in relation to aggressively placed fists, steering wheels and concrete.
Anatomically, the mandible consists of a symmetrical, horseshoe shaped body continuous with paired broad rami posteriorly. The former houses the lower teeth within the alveolus whilst the latter provides attachment for the four principle muscles of mastication from the its medial and lateral surfaces and coronoid and condylar processes. In addition to the aforementioned muscles of mastication, the mandible provides origin to the muscles of the tongue, the floor of mouth and some muscles of facial expression.
An overview of the anatomy and embryology of the face, head, and neck that is most relevant to the plastic surgeon is presented in this chapter. Subsections focus on the scalp, forehead, cheek, nose, ears, eyelid, lips, oral cavity, oropharynx, mandible, muscles of mastication, nasopharynx, hypopharynx, and larynx.
The mandible forms the lower face and supports the teeth, the diaphragm of the floor of mouth, and the mobile tongue. It articulates with the skull base via the temporomandibular joints and is controlled by the muscles of mastication. Fractures of the mandible are common and require accurate reduction and stable fixation, particularly in the dentate patient. The anatomy, pathology, and management of mandible fractures are described in this chapter.
Temporomandibular disorders usually represented as a group of painful as well as altered conditions involving the muscles of mastication and the muscles around the temporomandibular joint. Usually the patient are un aware of the condition. Temporomandibular joint disorders affects twenty five percent of the population. Temporomandibular disorders represent with musculoskeletal degenerative conditions of the joint which results in functional as well as morphological deformities of the temporomandibular joint. As temporomandibular disorders cases are complex with unique nature with respect to each case, so the diagnosis and treatment modality is quite different for each type of case.
Dysfunctions of Muscles of Mastication (MM) are commonly associated with facial pain, and it is a common medical condition in women's reproductive health. Hypothetically, sex hormones could be considered an underlying cause for this dysfunction, but few studies were done to explore sex hormones receptors in MM. The aim of the present study is to explore the effect of both age and sex on the expression of estrogen and androgen receptors in muscles of mastication. Eighty rats were randomly assigned into four groups. Group-12F, group-12M, group-24F and group-24M. After rats were sacrificed, MM were removed for histological and immunohistochemical examinations. Regardless age and sex, there was a weak expression of estrogen receptors (α,β) in all muscles. In group-24M, expression of androgen receptors in MM was significantly higher than that of other groups. In conclusion, the present study sheds the light on the age-related increased expression of androgen receptors in male albino wistar rats which could protect against temporomandibular muscles dysfunctions. Further studies are needed to evaluate this hypothesis for further clinical applications.
Recently, as we experienced a case of extranodal NHL originating from the masseter musclecompletely cured by chemotherapy with radiotherapy, we present the clinical, US, CT, andMR imaging findings in additional one case of biopsy-proved extranodal NHL (NK/T celllymphoma) involving predominantly the masseter muscle also review thoroughly our collectedcases of primary non-Hodgkin’s lymphoma involving the muscles of mastication and facialexpression. On the basis of our comprehensive review, we suggest two conclusions. First, primarymuscle lymphoma particularly originating from muscles of mastication and facial expression isextremely rare, but primary muscle lymphoma should be considered in the differential diagnosisof muscular masses. Second, primary muscle lymphoma particularly originating from muscles ofmastication and facial expression has similar clinical and radiological characteristics to primaryskeletal muscle lymphoma involving other sites. However, the prognosis is more favorablein primary muscle lymphoma originating from muscles of mastication and facial expressioncompared to primary skeletal muscle lymphoma involving other sites.
Bangladesh Journal of Medical Science Vol.20(1) 2021 p.181-186
Background: Trismus is a restricted mouth opening due to the tonic contraction of muscles of mastication. It may occur mostly in HNF cancer patients undergoing radiation therapy treatment. This study was undertaken with the purpose of finding out the prevalence of trismus in patients undergoing radiation therapy. Method: 89 patients with HNF cancer patients receiving radiation therapy were included in the study. Inter incisal distance was measured using sliding digital vernier calliper. Patients with ≥ 35mm mouth opening were considered as trismus cases. Result: Out of 89 patients included 72 were diagnosed as trismus; hence the prevalence was 81%. Conclusion: Prevalence of Trismus is very high ( 81 %) in patients undergoing radiotherapy secondary to HNF cancer. Early diagnosis of trismus in these patients can help in time management and also planning of preventive strategies.
Temporomandibular disorders (TMD) consist of multifactorial musculoskeletal disorders associated with the muscles of mastication, temporomandibular joint (TMJ), and annexed structures. This clinical condition is characterized by temporomandibular pain, restricted mandibular movement, and TMJ synovial inflammation, resulting in reduced quality of life of affected people. Commonly, TMD management aims to reduce pain and inflammation by using pharmacologic therapies that show efficacy in pain relief but their long-term use is frequently associated with adverse effects. For this reason, the use of natural compounds as an effective alternative to conventional drugs appears extremely interesting. Indeed, polyphenols could represent a potential therapeutic strategy, related to their ability to modulate the inflammatory responses involved in TMD. The present work reviews the mechanisms underlying inflammation-related TMD, highlighting the potential role of polyphenols as a promising approach to develop innovative management of temporomandibular diseases.
Expression of Androgen Receptors in Abating Age-Related Temporomandibular Muscles Dysfunctions in Female Albino Wistar Rats