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Sustentaculum tali

The sustentaculum tali is a medial shelf-like projection of the calcaneus that supports the talus. It lies on the superior-medial aspect of the calcaneus, providing an attachment site for multiple ligaments and forming a pulley for the flexor hallucis longus (FHL) tendon. Its name means “support of the talus,” reflecting its role in stabilizing the talus and subtalar joint.

The sustentaculum tali is clinically important as a landmark for surgery and a common site of injury in calcaneal fractures. Due to its close relationship with the FHL tendon and neurovascular structures, pathology in this region may lead to pain and tendon dysfunction.

Joints

  • Forms part of the subtalar joint (articulates with the talus above).

Ligament Attachments

  • Spring ligament (plantar calcaneonavicular ligament): Attaches from sustentaculum tali to navicular, supporting talar head.

  • Deltoid ligament (tibiocalcaneal fibers): Medial ankle stabilizer attaching to sustentaculum.

  • Talocalcaneal ligaments: Medial talocalcaneal ligament attaches directly to sustentaculum tali.

Tendon and Muscle Relations

  • Flexor hallucis longus tendon: Passes in a groove beneath the sustentaculum tali, using it as a pulley.

  • Tibialis posterior and flexor digitorum longus tendons: Pass nearby along the medial calcaneus but not directly on the shelf.

  • No direct muscular attachment to the sustentaculum tali itself.

Nerve Supply

  • Tibial nerve branches: Medial calcaneal branches provide innervation to surrounding structures.

  • Deep peroneal nerve: Minor articular contribution to subtalar joint.

Arterial Supply

  • Posterior tibial artery branches: Medial calcaneal arteries supply sustentaculum tali region.

  • Peroneal artery branches: Contribute small collateral supply.

Venous Drainage

  • Venous plexuses drain into posterior tibial and peroneal veins.

Function

  • Support: Acts as a shelf to support the talus and subtalar joint.

  • Pulley: Provides a smooth surface for the flexor hallucis longus tendon.

  • Stability: Anchors important ligaments for medial ankle and arch support.

  • Landmark: Serves as a key surgical landmark in medial hindfoot procedures.

Clinical Significance

  • Fractures: Commonly involved in calcaneal fractures; displacement may disrupt subtalar mechanics.

  • FHL tendonitis: Compression in the groove beneath sustentaculum tali causes pain and restricted motion.

  • Tarsal coalition: Calcaneonavicular or talocalcaneal coalition may involve the region.

  • Surgical importance: Medial approach landmark for calcaneal fracture fixation and subtalar joint surgery.

MRI Appearance

  • T1-weighted images:

    • Normal sustentaculum tali: cortical bone dark (low signal), marrow intermediate-to-high signal depending on fat content.

    • Fractures: linear low-signal cortical break with surrounding marrow signal changes.

    • AVN or sclerosis: diffuse low signal marrow.

  • T2-weighted images:

    • Normal marrow: intermediate-to-high signal depending on fat.

    • Cortical bone: dark low signal.

    • Fractures/edema: bright hyperintense marrow with low-signal cortical break.

    • FHL tendonitis: increased fluid signal around tendon groove.

  • STIR:

    • Normal marrow suppressed (dark).

    • Pathology (fractures, edema, tendon inflammation): bright hyperintense signal.

  • Proton Density Fat-Saturated (PD FS):

    • Normal: homogeneous dark marrow, low-signal cortex.

    • Pathology: bright signal areas highlight bone bruises, subtle fractures, or tendon irritation beneath sustentaculum.

  • T1 Fat-Sat Post-Contrast:

    • Normal: uniform mild enhancement of marrow.

    • Fractures or inflammatory changes: enhancement at marrow/soft tissue interface.

    • FHL tenosynovitis: enhancing synovial sheath around tendon groove.

MRI Arthrogram Appearance

  • Contrast outlines subtalar joint surface above sustentaculum tali.

  • Subtle cartilage lesions: contrast penetration into joint defects.

  • May highlight FHL sheath pathology when communicating with subtalar joint effusion.

CT Appearance

Non-Contrast CT:

  • Provides excellent cortical bone definition.

  • Sustentaculum tali fractures: clearly seen as cortical disruption or displacement.

  • Useful for evaluating calcaneal fracture patterns involving subtalar joint.

CT Arthrogram Appearance

  • Contrast outlines subtalar joint and sustentaculum surface.

  • Cartilage defects: contrast penetration into subchondral lesions.

  • Highlights intra-articular extension of fractures.

  • Valuable alternative when MRI is contraindicated.

CT VRT 3D image

Sustentaculum tali

MRI image

Sustentaculum tali MRI sagittal cross sectional anatomy 3T MRI AI enhanced radiology image-img-00000-00000

CT image

Sustentaculum tali sagittal CT cross sectional anatomy radiology image-img-00000-00000