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Posterior talar articular facet

The posterior talar articular facet of the calcaneus is the largest and most important articular surface of the calcaneus, located on its superior surface. It articulates with the posterior facet of the talus, forming the posterior subtalar joint. This joint is essential for hindfoot inversion and eversion, transmitting forces from the talus to the calcaneus during gait.

The facet is covered by hyaline cartilage and supported by strong ligaments, making it crucial for hindfoot biomechanics. It is a common site of degenerative arthritis, subtalar dislocation, and post-traumatic changes, especially following calcaneal or talar fractures.

Joints

  • Forms the posterior subtalar joint, the main articulation between talus and calcaneus

Ligament Attachments

  • Interosseous talocalcaneal ligament: Stabilizes subtalar joint within sinus tarsi

  • Cervical ligament: Connects calcaneus to talus laterally

  • Medial, lateral, and posterior talocalcaneal ligaments: Reinforce subtalar articulation

  • Deltoid ligament (indirect support): Provides medial stability through talus

Tendon and Muscle Relations

  • Medial side: Tibialis posterior and flexor digitorum longus tendons course medially

  • Lateral side: Peroneal tendons pass adjacent to calcaneus but do not attach to the facet

  • Posteriorly: Achilles tendon attaches to calcaneal tuberosity (not directly related to facet but close in projection)

Nerve Supply

  • Tibial nerve branches: Medial and lateral plantar articular nerves supply the facet region

  • Sural nerve: Provides lateral subtalar joint innervation

  • Deep peroneal nerve: Minor contributions anteriorly

Arterial Supply

  • Posterior tibial artery: Provides branches via artery of tarsal canal

  • Dorsalis pedis artery: Supplies region via artery of tarsal sinus

  • Peroneal artery: Contributes lateral vascular branches

Venous Drainage

  • Drains into posterior tibial, peroneal, and dorsalis pedis veins

Function

  • Provides a stable articulating surface for subtalar joint

  • Allows hindfoot inversion and eversion during gait

  • Transmits forces from talus to calcaneus, contributing to shock absorption

Clinical Significance

  • Arthritis: Common site of subtalar osteoarthritis, especially post-traumatic

  • Fractures: Intra-articular calcaneal fractures often involve posterior facet

  • Coalitions: Talocalcaneal coalitions may involve posterior facet and restrict motion

  • Surgical relevance: Accurate reduction of posterior facet fractures is essential to restore subtalar function

MRI Appearance

  • T1-weighted images:

    • Normal cortical bone of facet: low signal (dark)

    • Subchondral marrow: intermediate-to-high signal depending on fat content

    • Arthritis or fracture: low-signal lines or irregular cortical defects

  • T2-weighted images:

    • Cartilage: intermediate-to-high signal depending on hydration

    • Cortical bone: dark low signal

    • Subchondral bone marrow edema: bright hyperintense signal

    • Osteochondral defects: focal areas of cartilage loss with underlying high-signal edema

  • STIR:

    • Normal marrow suppressed dark

    • Pathology (fractures, arthritis, edema): bright hyperintense signal

  • Proton Density Fat-Saturated (PD FS):

    • Normal: homogeneous low signal in cortical rim, intermediate in marrow

    • Pathology: bright signal within marrow and cartilage defects

    • Excellent for early detection of osteochondral changes and arthritis

  • T1 Fat-Sat Post-Contrast:

    • Normal: minimal uniform enhancement

    • Inflammatory arthritis or post-traumatic change: enhancing synovium and marrow

    • AVN-like pathology: non-enhancing necrotic areas with rim enhancement

MRI Arthrogram Appearance

  • Contrast fills the posterior subtalar joint

  • Cartilage defects: contrast outlines or penetrates lesions

  • Detects subtle osteochondral damage and synovitis not well seen on standard MRI

CT Appearance

Non-Contrast CT:

  • Cortical bone: high-density, sharply defined

  • Excellent for evaluating fractures and subchondral sclerosis

  • Arthritis: visible as osteophytes, joint space narrowing, subchondral cysts

CT Arthrogram Appearance

  • Contrast clearly outlines the posterior subtalar joint surface

  • Cartilage loss: contrast pooling into subchondral bone

  • Subtle chondral defects and osteochondral lesions well visualized

  • Valuable alternative to MRI in patients with contraindications

MRI image

Posterior Talar Articular Facet of the Calcaneus agittal MRI cross sectional anatomy 3T MRI AI enhanced radiology image-img-00000-00000

CT image

posterior talar articular surface sagittal CT cross sectional anatomy radiology image-img-00000-00000