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Topic

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Articular eminence

The articular eminence is an essential anatomical structure of the temporal bone, forming the anterior boundary of the mandibular fossa and playing a critical role in temporomandibular joint (TMJ) function. Its morphology and signal characteristics on MRI are crucial for evaluating TMJ disorders and other maxillofacial pathologies.

Description

  • The articular eminence is a rounded, bony ridge located on the inferior aspect of the temporal bone, anterior to the glenoid fossa.

  • It acts as the anterior articulation point for the mandibular condyle during mouth opening and closing movements.

  • It provides stability to the TMJ and guides mandibular motion.

  • Its slope and shape can vary significantly between individuals and may influence TMJ biomechanics.

Synonyms

  • Eminentia articularis (Latin)

  • Glenoid eminence

  • Articular tubercle

  • Zygomatic process of temporal bone (context-dependent)

MRI Appearance

On Proton Density (PD) Sequence:

  • The articular eminence appears as a well-defined, low-signal-intensity (dark) bony structure due to its dense cortical bone composition.

  • The overlying fibrocartilage may appear as a thin, intermediate to low-signal-intensity line.

  • Adjacent soft tissues (such as the articular disc and joint capsule) are better delineated in relation to the eminence on PD imaging.

On Short Tau Inversion Recovery (STIR) Sequence:

  • The cortical bone of the articular eminence remains hypointense (dark) on STIR, similar to other bony structures.

  • STIR is highly sensitive for detecting bone marrow edema or inflammation. In normal cases, the bone marrow within the articular eminence appears dark, but areas of edema or pathology (e.g., trauma, arthritis) would show high-signal-intensity (bright) changes.

  • The fibrocartilage layer, if visualized, remains low to intermediate in signal.

MRI images

Articular eminence