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Posterior calcaneal articular facet

The posterior calcaneal articular facet is the largest and most important articular surface of the calcaneus, forming the principal component of the subtalar joint. It articulates with the posterior talar facet and plays a crucial role in hindfoot motion, particularly inversion and eversion.

It is a key structure in foot anatomy, biomechanics, trauma assessment, and imaging of the hindfoot and subtalar joint.

Synonyms

  • Posterior talar facet of the calcaneus

  • Posterior subtalar facet

Location

  • Situated on the superior surface of the calcaneus

  • Posterior to the sustentaculum tali

  • Inferior to the talus

  • Forms the posterior compartment of the subtalar joint

  • Separated from middle facet by the calcaneal sulcus

Anatomical components

  • Hyaline cartilage-covered articular surface

  • Convex or slightly concave contour

  • Subchondral bone plate beneath the cartilage

  • Margins contributing to subtalar joint congruity

Relations

Superiorly:

  • Posterior articular facet of the talus

Inferiorly:

  • Calcaneal body

Anteriorly:

  • Calcaneal sulcus

  • Middle calcaneal articular facet

Posteriorly:

  • Posterior calcaneal tuberosity

Medially:

  • Sustentaculum tali

Laterally:

  • Lateral process of the calcaneus

X-ray appearance

Plain radiographs (lateral, axial, and Broden views):

  • Posterior facet: Seen as a smooth, curvilinear subchondral line on lateral views

  • Subtalar joint space: Clearly visualized between talus and calcaneus

  • Best demonstrated on: Broden and lateral views

CT appearance

Non-contrast CT:

  • Posterior facet: Well-defined, smooth cortical articular surface

  • Subchondral bone: Uniform density beneath the articular surface

  • Joint congruity: Clearly visualized

  • Excellent spatial resolution for evaluating articular contour and alignment

MRI appearance

T1-weighted images:

  • Subchondral bone: High signal marrow with low-signal cortical margin

  • Articular cartilage: Intermediate to low signal

  • Facet contour: Clearly delineated

T2-weighted images:

  • Articular cartilage: Intermediate-to-high signal

  • Joint fluid: High signal outlining the posterior facet

  • Subchondral bone: Low-to-intermediate signal

STIR:

  • Fat-suppressed marrow: Uniform low signal

  • Joint fluid: Bright signal

  • Facet margins: Well visualized against suppressed marrow

Proton density fat-saturated (PD FS):

  • Articular cartilage: Well-defined intermediate signal

  • Joint fluid: High signal

  • Subchondral bone: Suppressed marrow signal

MRI image

Posterior calcaneal articular facet mri anatomy labelled image-img-00000-00000