Dislocation of Mandibular Disc

Vocabulary practice flashcards covering conditions, causes, symptoms, and diagnostic mechanisms related to dislocation and dysfunction of the mandibular disc.

Irregular Disc Location

A condition characterized by irregular clicks, no pain during articulation (or periodic pain from bruxism), tenderness upon palpation of the TMJ and chewing muscles, and a mouth opening range of $40\text{--}60\,\text{mm}$ with possible deviation in the sagittal plane that returns to center at the end of range.

Joint Adhesion (Impaired Joint Lubrication)

A state where articular surfaces stick together even with sufficient fluid, caused by impaired lubrication and prolonged static load such as clenching, bruxism, or lack of joint movement.

Articular Surface Defects

Structural joint abnormalities caused by macro- or microtrauma, pathological joint movement (true adhesion), developmental or growth anomalies, or inflammation, typically presenting with a click occurring at the exact same point of opening, occasional deviation, and usually no pain.

Adhesion Risk Factors (Articular Surface Defects)

Specific clinical conditions that elevate the risk of joint adhesion, specifically trauma occurring with a closed mouth and hemarthrosis (blood breakdown).

Disc Thinning & Perforation

A condition where the mandibular disc flattens (often associated with dislocation) or perforates due to sudden force or excessive pressure, presenting with clicking and jamming similar to dislocation at a consistent opening point, with pain decreasing as the perforation enlarges.

Partial Anterior-Medial / Anterior-Lateral Dislocation

Displacement where forward movement is limited by ligament length and posterior zone thickness, caused by thinning of the posterior zone and elongated ligaments; characterized by no clicks and slight deviation returning to the midline.

Dislocation with Temporary Limited Opening

A condition where the disc changes from concave to convex after prolonged dislocation, causing the condyle to struggle to return to position; manifests as occasional limited opening mostly in the mornings and can progress to dislocation without reduction if untreated.

Disc Dislocation with Reduction

Displacement caused by continuous forward and medial pull by the lateral pterygoid along with elongated and thinned posterior laminae, characterized clinically by reciprocal clicking during jaw movement.

Reciprocal Clicking

A two-phase clicking pattern consisting of an opening click (as the condyle passes the posterior border of the disc into its intermediate zone) and a closing click (as disc morphology and the lateral pterygoid pull the disc forward again).

Disc Dislocation without Reduction

Displacement caused by rapid changes in joint dimensions, nocturnal bruxism, or prolonged lateral pterygoid contraction in the absence of posterior tooth support.

Chronic Disc Dislocation without Reduction

The long-term stage of non-reducing disc displacement, presenting with jaw opening that is slightly limited or normal, accompanied by a small deviation toward the affected side.