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Lateral malleolar facet of talus

The lateral malleolar facet of the talus is a smooth articular surface on the lateral aspect of the talus that articulates with the medial surface of the lateral malleolus (fibula). It forms a critical component of the ankle mortise and plays an essential role in load transmission and stability of the ankle joint.

It is a key anatomical landmark in ankle anatomy, trauma evaluation, sports medicine, and cross-sectional imaging of the ankle.

Synonyms

  • Fibular articular facet of the talus

  • Lateral talar facet

Location

  • Situated on the lateral surface of the talus

  • Opposite the lateral malleolus of the fibula

  • Forms the lateral wall of the ankle joint articulation

  • Lateral to the talar trochlea

  • Inferior to the fibular plafond

Anatomical components

  • Hyaline cartilage–covered articular surface

  • Underlying subchondral bone plate

  • Continuous with:

    • Trochlear surface of the talus superiorly

    • Posterior and anterior talar articular margins

  • Joint interface:

    • Articulates with the medial surface of the lateral malleolus

Relations

Laterally:

  • Lateral malleolus (fibula)

Medially:

  • Body of the talus and talar trochlea

Anteriorly:

  • Anterior talofibular ligament (ATFL)

  • Anterior ankle joint capsule

Posteriorly:

  • Posterior talofibular ligament (PTFL)

  • Posterior ankle capsule

Superiorly:

  • Trochlear surface of the talus

Inferiorly:

  • Subtalar joint components

X-ray appearance

Plain radiographs (AP, mortise, and lateral ankle views):

  • Facet: Seen indirectly as part of the talar lateral articular contour

  • Mortise view: Best demonstrates the articulation between talus and fibula

  • Joint space: Uniform and symmetric laterally

  • Subchondral bone: Appears smooth and continuous

CT appearance

Non-contrast CT:

  • Facet: Well-defined smooth articular surface on the lateral talus

  • Subchondral bone: Thin dense cortical plate beneath cartilage

  • Contour: Conforms precisely to the fibular malleolar surface

  • Spatial detail: Excellent visualization of surface geometry

MRI appearance

T1-weighted images:

  • Subchondral bone: Low signal cortical line with high-signal marrow deep to it

  • Articular cartilage: Intermediate signal layer over the facet

  • Facet margins: Clearly defined

T2-weighted images:

  • Articular cartilage: Intermediate-to-high signal relative to bone

  • Joint fluid: High signal outlining the articular surface

  • Subchondral bone: Low signal

STIR:

  • Fat suppression: Uniform suppression of talar marrow fat

  • Articular surface: Well visualized against bright joint fluid

  • Surrounding soft tissues: High contrast

Proton density fat-saturated (PD FS):

  • Cartilage–bone interface: Clearly delineated

  • Joint fluid: Bright signal

  • Facet margins: Sharply defined

CT VRT 3D image

Lateral malleolar facet of talus 3d

MRI image

Lateral malleolar facet of talus mri anatomy labelled image-img-00000-00000

MRI image

Lateral malleolar facet of talus mri anatomy labelled image-img-00000-00000_00001