Anatomy and Biodynamics Applied to the Temporomandibular Joint Complex

Vocabulary flashcards covering the anatomical components, ligamentous and muscular systems, biodynamics, condylar trajectories, angles, formulas, and biomechanics of the temporomandibular joint complex.

Anatomical and functional system comprising the jaws, teeth, temporomandibular joints, and associated structures

Stomatognathic System

Anatomical classification of the TMJ, featuring two articulating surfaces covered with fibrocartilage that function as a single bilateral unit

Bicondylar Diarthrodial Joint

Lower articulating surface of the TMJ, whose convex superior and anterior aspects are covered with fibrocartilage

Mandibular Condyle

Upper articulating surface of the TMJ located within the glenoid fossa, bordered posteriorly by Glasser's fissure and anteriorly by the articular eminence

Temporal Bone (TMJ Articular Surface)

Elliptical fibrocartilaginous structure with an S-curve in the sagittal plane that accommodates incongruent joint surfaces and divides the TMJ into two cavities

Articular Disc (Meniscus)

Joint cavity located between the articular disc and the temporal bone, responsible for translational movement

Suprameniscal Cavity

Joint cavity located between the articular disc and the mandibular condyle, responsible for rotational movement

Inframeniscal Cavity

Fibrous cone formed by superficial and deep fiber planes surrounding the TMJ, absent anterointernally where the external pterygoid tendon fuses with the meniscus

Synovial Capsule

Blood dialysate containing high levels of hyaluronic acid and mucopolysaccharides that functions to nourish and lubricate TMJ elements

Synovial Fluid

Lateral reinforcement of the capsule that stabilizes the TMJ laterally and prevents posterior displacement of the condyle

Temporomandibular Ligament

TMJ ligament that limits excessive forward movement of the condyle and disc, contributing to controlled retrusion

Posterior Ligament

Muscle bundle originating at the sphenoid bone and inserting into the articular disc, responsible for stabilizing the disc during closure and guiding its movement

Superior Head of Lateral Pterygoid Muscle

Muscle bundle inserting into the neck of the mandibular condyle, pulling the condyle forward during opening, lateralization, and protrusion

Inferior Head of Lateral Pterygoid Muscle

Horizontal axis around which pure condylar rotation occurs within the inframeniscal cavity during initial mouth opening up to $20\,\text{mm}$

Terminal Hinge Axis

Pure turning movement of the condyle on the meniscus around the terminal hinge axis within the inframeniscal cavity, occurring during initial opening up to $20\,\text{mm}$

Rotational Movement (TMJ)

Sliding movement of the meniscus and condyle forward and downward along the articular eminence within the suprameniscal cavity when opening exceeds $20\,\text{mm}$

Translational Movement (TMJ)

Separation created between the posterior teeth of the upper and lower arches during protrusive condylar movement

Christensen's Phenomenon

Angle formed by the condylar trajectory with the horizontal Frankfurt or Virchow plane

Condylar Slope Angle

Downward, forward, and inward trajectory described by the non-working side condyle during lateral movement

Internal Laterality Trajectory (Non-Working Side)

Angle measured between the non-working condyle trajectory and the protrusive trajectory in relation to the sagittal plane

Fisher's Angle

Angle formed on the horizontal plane between the non-working condyle trajectory during lateral movement and its trajectory during protrusion

Bennett's Angle

Formula used to calculate Bennett's angle from the condylar slope angle: $\text{Bennett's Angle} = \frac{\text{Condylar Slope Angle}}{8} + 12^\circ$

Hanau's Formula

Formula used to calculate Bennett's angle from the condylar slope angle: $\text{Bennett's Angle} = \frac{\text{Condylar Slope Angle}}{6} + 18^\circ$

Forcén's Formula

Outward and backward path described by the working-side condyle during lateral excursion

External Laterality Trajectory (Working Side)

Lateral movement of the working-side condyle (and entire mandible) occurring within a 3D conical space of $60^\circ$ width, $3\,\text{mm}$ height, and $1\text{ to }2\,\text{mm}$ amplitude

Immediate Bennett's Movement

Mechanical lever model where support/fulcrum is at the TMJ, power is exercised in the center by muscles, and resistance is located at the teeth

Third Type Lever (TMJ Mechanics)

Attachment structure of the tooth composed of root cementum joined to alveolar cortical bone by periodontal ligaments

Insertion Parodontium

Tissue system formed by mobile and attached mucosa surrounding and protecting the teeth

Protection Parodontium

Tissue injury resulting when antagonistic dental contacts occur on inclined planes, generating non-axial transverse forces that stimulate osteoclasts and lead to bone resorption

Occlusal Trauma

Three-point contact scheme on occlusal surfaces designed to direct resultant masticatory forces along the long functional axis of the tooth

Tripodic Support