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Topic

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Articular facet of lateral malleolus

The articular facet of the lateral malleolus is the smooth, cartilage-covered surface on the medial aspect of the distal fibula that articulates with the lateral surface of the talus. It forms an essential component of the ankle mortise and plays a critical role in maintaining congruency and stability of the ankle joint.

It is an important anatomical landmark in ankle biomechanics, trauma evaluation, and cross-sectional imaging.

Synonyms

  • Talofibular articular surface

  • Fibular articular facet for the talus

Location

  • Situated on the medial surface of the distal fibula

  • Part of the lateral malleolus

  • Lateral to the talar dome

  • Inferior to the distal tibiofibular syndesmosis

  • Forms the lateral wall of the ankle mortise

Anatomical components

  • Hyaline cartilage-covered bony surface

  • Subchondral cortical bone

  • Underlying cancellous bone of the fibula

  • Margins blending with the non-articular fibular cortex

Relations

Medially:

  • Lateral articular surface of the talus

Laterally:

  • Cortex of the distal fibula

Anteriorly:

  • Anterior talofibular ligament attachment nearby

Posteriorly:

  • Posterior talofibular ligament attachment nearby

Superiorly:

  • Distal tibiofibular syndesmosis

Inferiorly:

  • Talus and ankle joint cavity

X-ray appearance

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

  • Articular facet: Seen as a smooth, well-defined surface on the medial side of the lateral malleolus

  • Joint space: Uniform space between talus and fibula on mortise view

  • Best visualized on: Mortise view of the ankle

CT appearance

Non-contrast CT:

  • Articular facet: Smooth, sharply defined cortical surface

  • Subchondral bone: Uniform density beneath cartilage

  • Contour: Concave surface matching talar curvature

  • Joint congruency: Clearly appreciated

  • Useful for: Precise assessment of articular surface geometry

MRI appearance

T1-weighted images:

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

  • Articular cartilage: Thin low-to-intermediate signal layer over the facet

  • Facet contour: Clearly outlined

T2-weighted images:

  • Articular cartilage: Intermediate-to-high signal

  • Joint fluid: High signal outlining the articular surface

  • Cortical margins: Low signal

STIR:

  • Fat suppression: Highlights joint fluid and surrounding soft tissues

  • Articular margins: Well delineated

  • Ligaments: Low-signal structures adjacent to the facet

Proton density fat-saturated (PD FS):

  • Articular cartilage: Well visualized against suppressed marrow

  • Joint space: High signal

  • Subchondral bone: Clear contrast with overlying cartilage

CT VRT 3D image

Articular facet of lateral malleolus 3d

MRI image

Articular facet of lateral malleolus mri anatomy labelled image-img-00000-00000

CT image

Articular facet of lateral malleolus ct