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Lateral process of talus

The lateral process of the talus is a prominent bony projection arising from the lateral aspect of the talar body. It forms an important part of the subtalar and ankle joints and contributes to the stability and articulation between the talus, fibula, and calcaneus.

It is a key anatomical landmark in ankle and hindfoot anatomy and is especially important in trauma imaging and orthopedic assessment.

Synonyms

  • Lateral talar process

  • External process of the talus

Location

  • Situated on the lateral aspect of the talar body

  • Inferior to the lateral malleolus

  • Superior to the calcaneus

  • Lateral to the talar dome

  • Forms part of the subtalar joint articulation

Anatomical components

  • Osseous projection of the talus

  • Articular surfaces:

    • Superior facet contributing to the ankle joint

    • Inferior facet articulating with the calcaneus (subtalar joint)

  • Ligament attachment sites:

    • Talofibular ligament fibers

    • Components of the lateral collateral ligament complex

Relations

Anteriorly:

  • Talonavicular joint region

Posteriorly:

  • Posterior talar process

Laterally:

  • Distal fibula and lateral malleolus

Medially:

  • Talar body and dome

Inferiorly:

  • Calcaneus

Superiorly:

  • Ankle joint space

X-ray appearance

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

  • Lateral process: Appears as a small triangular bony projection lateral to the talus

  • Best seen on: Oblique and lateral views

  • Cortical margins: Sharp and well-defined

  • Relationship: Positioned between the fibula and calcaneus

CT appearance

Non-contrast CT:

  • Lateral process: Clearly defined bony projection from the talus

  • Cortical outline: Smooth and sharply demarcated

  • Trabecular pattern: Normal cancellous bone texture

  • Articular surfaces: Well visualized with adjacent calcaneus and fibula

  • Spatial assessment: Excellent for evaluating size, shape, and contour

MRI appearance

T1-weighted images:

  • Cortical bone: Low signal intensity

  • Marrow within lateral process: High signal intensity

  • Contour: Well delineated against surrounding soft tissues

T2-weighted images:

  • Cortex: Low signal

  • Joint spaces: High signal outlining articular margins

  • Surrounding ligaments: Low-to-intermediate signal

STIR:

  • Fat suppression: Uniform suppression of marrow fat

  • Lateral process margins: Clearly visualized

  • Adjacent joint fluid: Bright signal

Proton density fat-saturated (PD FS):

  • Bone marrow: Suppressed fat signal

  • Articular cartilage and joint fluid: High signal contrast

  • Ligamentous attachments: Seen as low-signal bands

CT VRT 3D image

Lateral process of talus 3d

MRI image

Lateral process of talus mri anatomy labelled image-img-00000-00000

MRI image

Lateral process of talus mri anatomy labelled image-img-00000-00000_00001