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Posterior process

The posterior process of the talus is a bony projection arising from the posterior aspect of the talus and forming an important part of the ankle and subtalar joint complex. It is composed of medial and lateral tubercles separated by a groove for the flexor hallucis longus tendon and plays a key role in hindfoot anatomy and biomechanics.

It is a critical structure in ankle imaging, trauma evaluation, posterior ankle impingement syndromes, and surgical planning.

Synonyms

  • Posterior talar process

  • Posterior tubercles of the talus

Location

  • Situated at the posterior aspect of the talus

  • Posterior to the talar body

  • Inferior to the tibial plafond

  • Superior to the calcaneus

  • Between the ankle and subtalar joints

Anatomical components

  • Medial tubercle:

    • Smaller projection

    • Gives attachment to part of the posterior talotibial ligament

  • Lateral tubercle:

    • Larger and more prominent

    • May develop as a separate ossicle (os trigonum if unfused)

  • Intertubercular groove:

    • Lodges the tendon of flexor hallucis longus (FHL)

  • Articular relationships:

    • Contributes to both ankle and subtalar joint surfaces

Relations

Anteriorly:

  • Body of the talus

Posteriorly:

  • Posterior ankle joint capsule

  • Posterior talofibular ligament

Medially:

  • Flexor hallucis longus tendon (groove)

  • Posterior talotibial ligament

Laterally:

  • Posterior talofibular ligament

  • Fibula (indirect relationship)

Inferiorly:

  • Calcaneus (subtalar joint)

Superiorly:

  • Distal tibia and ankle joint

X-ray appearance

Plain radiographs (lateral ankle view best):

  • Posterior process: Seen as a bony projection posterior to the talar body

  • Medial and lateral tubercles: May appear as a single or bilobed structure

  • Os trigonum: Appears as a separate rounded ossicle posterior to the talus if present

  • Best visualized on: Lateral and oblique ankle views

CT appearance

Non-contrast CT:

  • Posterior process: Well-defined bony projection from the talus

  • Cortical margins: Sharp and smooth

  • Medial and lateral tubercles: Clearly distinguishable

  • FHL groove: Seen as a sulcus between the tubercles

  • Os trigonum differentiation: Excellent for determining fusion versus separate ossicle

  • Relationship to joints: Precisely demonstrated

MRI appearance

T1-weighted images:

  • Cortical bone: Low signal intensity

  • Marrow within tubercles: High signal

  • FHL tendon: Low-signal structure within the intertubercular groove

T2-weighted images:

  • Cortex: Low signal

  • Joint fluid: High signal outlining the posterior process

  • FHL tendon: Low signal surrounded by higher-signal fluid or sheath

STIR:

  • Marrow fat suppression: Uniform

  • Posterior process margins: Well delineated

  • FHL tendon and sheath: Clearly visible against suppressed marrow

Proton density fat-saturated (PD FS):

  • Bone marrow: Suppressed fat signal

  • Joint fluid and tendon sheaths: High signal

  • FHL tendon: Seen as low-signal linear structure

CT VRT 3D image

Posterior process of talus 3d

MRI image

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

MRI image

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