Movements of the Mandible and Temporomandibular Joint during Jaw Opening and Closing
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Because of their complexity, the movements of the mandible during chewing and those of the temporomandibular joint or TMJ are typically difficult for students to visualize. These animations were created to aid dental and medical students in visualization of the components of these movements that are the most challenging: the movements of the mandible in the frontal (coronal) plane and the movements of the TMJ and its intraarticular structures in the sagittal plane. The mandible animation illustrates the typical movement path followed during the opening and closing movements of unilateral mastication. The animation can be stopped at three different points during the movement envelope: following full opening, following closing to approximate the teeth, and just prior to the power stroke. In my teaching, I have paired this animation with a simple PowerPoint (included) that highlights the muscles that are active during the opening and closing phases. This juxtaposition helps to emphasize the phasic yet synergistic contributions of the numerous muscles that produce these complex movements. The temporomandibular joint animation illustrates the movement of the mandibular condyle, the articular disc, and the retrodiscal pad (posterior attachment) during opening and closing movements of the lower jaw. In my teaching, the TMJ animation permits me to highlight the differential movements of the intraarticular structures and to discuss factors that affect these movements.
This resource was created to portray the complex movements of the mandible and of the intraarticular structures of the TMJ in a more understandable way than static positional drawings could. Students at my institution seem to think that these animations significantly aid their comprehension of how mastication is effected and how the disc moves relative to the condyle.
Hinton R, Hutchins B, Hill G. Movements of the mandible and temporomandibular joint during jaw opening and closing. MedEdPORTAL Publications. 2011;7:8464. http://dx.doi.org/10.15766/mep_2374-8265.8464
Contains Information Suitable for Patient Education
After viewing this educational resource, students should be able:
- To describe the typical path taken by the mandible in frontal view during jaw opening and closing and understand why this path is functionally necessary as a part of the masticatory process.
- To list the specific muscles that contract to move the mandible along each portion of this envelope of motion.
- To understand the two types of movements that occur simultaneously in the TMJ during the opening/ closing cycle and the localization of these movements to subdivisions of the joint cavity.
- To discuss the differential movements of the articular disc and retrodiscal pad relative to the condylar head during opening and closing.
- Temporomandibular Joint, Articular Disc, Mastication, Mandibular Condyle, Jaw, Mandible
Prior Scholarly Dissemination
This information is made available under the Creative Commons license.
Authors & Co-Authors
Baylor College of Dentistry, A Member of The Texas A&M University
Bob Hutchins, PhD
Baylor College of Dentistry
Gerald Hill, LATg
Baylor College of Dentistry