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Posterior band of articular disc, TMJ

The posterior band of the articular disc in the temporomandibular joint (TMJ) is the thickest portion of the biconcave fibrocartilaginous disc that separates the mandibular condyle from the glenoid fossa of the temporal bone. This band plays a crucial role in TMJ biomechanics by maintaining the disc position during mandibular movements and preventing posterior displacement of the condyle. Anatomically, the posterior band is located posteriorly within the joint, lying between the condyle and the posterior glenoid fossa, and is attached superiorly to the temporal bone and inferiorly to the posterior condylar neck via the bilaminar zone.

Synonyms

  • Posterior band of the TMJ disc

  • Posterior zone of the articular disc

  • Posterior margin of the articular disc

  • Posterior lamina (in some anatomical texts)

  • Posterior thick zone of TMJ disc

MRI Appearance

  • PD (Proton Density) Sequence

    • The posterior band appears as a well-defined, low signal intensity structure due to its fibrocartilaginous nature.

    • It is seen interposed between the mandibular condyle and the posterior aspect of the glenoid fossa.

    • The posterior band is usually thicker and more conspicuous than the anterior and intermediate bands.

    • In normal joints, it is best visualized on sagittal and coronal PD images.

    • Helps to assess disc position (normal: posterior band at the 12 o’clock position relative to the condyle when the mouth is closed).

  • STIR (Short Tau Inversion Recovery) Sequence

    • The posterior band remains low in signal intensity, while the surrounding joint fluid and inflamed soft tissues appear hyperintense.

    • Useful for detecting joint effusion or inflammatory changes around the disc, but the disc itself (including the posterior band) maintains a hypointense signal.

    • The interface between the low-signal posterior band and high-signal effusion or synovitis may be clearly delineated.

MRI images

Posterior band of articular disc