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Posterior colliculus of medial malleolus

The posterior colliculus of the medial malleolus is a bony prominence located on the posterior aspect of the medial malleolus of the tibia. It forms part of the posterior contour of the medial ankle and serves as an important attachment site for deep ligamentous structures, contributing to medial ankle stability and guidance of surrounding tendons.

It is an important landmark in ankle anatomy, trauma evaluation, and cross-sectional imaging of the medial ankle.

Synonyms

  • Posterior tubercle of the medial malleolus

  • Posterior collicular process

Location

  • Situated on the posterior aspect of the medial malleolus

  • Inferior to the tibial plafond

  • Posterior to the anterior colliculus

  • Medial to the talus

  • Forms part of the medial wall of the ankle mortise

Anatomical components

  • Osseous projection of the distal tibia

  • Cortical shell with underlying cancellous bone

  • Ligament attachment site:

    • Deep fibers of the deltoid ligament

    • Posterior tibiotalar ligament

  • Groove relationship:

    • Lies adjacent to the groove for the posterior tibial tendon

Relations

Anteriorly:

  • Anterior colliculus of the medial malleolus

  • Tibiotalar joint capsule

Posteriorly:

  • Posterior tibial tendon and its sheath

  • Flexor digitorum longus tendon (nearby)

Medially:

  • Subcutaneous tissue and skin

Laterally:

  • Medial articular surface of the talus

Inferiorly:

  • Medial surface of the talus

Superiorly:

  • Distal tibial metaphysis and plafond

X-ray appearance

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

  • Posterior colliculus: Subtle bony prominence on the posterior margin of the medial malleolus

  • Best appreciated on: Lateral and oblique views

  • Cortical outline: Smooth and continuous

CT appearance

Non-contrast CT:

  • Posterior colliculus: Clearly defined bony protuberance on the posterior aspect of the medial malleolus

  • Cortical margins: Smooth and sharply delineated

  • Trabecular pattern: Normal cancellous bone

  • Spatial detail: Excellent visualization of its contour and relationship to adjacent grooves

MRI appearance

T1-weighted images:

  • Cortical bone: Low signal intensity

  • Marrow: High signal within the medial malleolus

  • Posterior colliculus contour: Well delineated against surrounding soft tissues

T2-weighted images:

  • Cortex: Low signal

  • Adjacent joint fluid: High signal outlining the posterior aspect

  • Ligamentous attachments: Low-to-intermediate signal bands

STIR:

  • Fat suppression: Uniform suppression of marrow fat

  • Colliculus margins: Clearly visible

  • Tendon sheaths and joint fluid: Bright signal

Proton density fat-saturated (PD FS):

  • Bone marrow: Suppressed fat signal

  • Joint fluid: High signal

  • Deep deltoid ligament fibers: Well visualized attaching to the posterior colliculus

CT VRT 3D image

Posterior colliculus of medial malleolus 3d

MRI image

Posterior colliculus of medial malleolus mri anatomy labelled image-img-00000-00000