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Medioplantar oblique calcaneonavicular ligament

The medioplantar oblique calcaneonavicular ligament is the strongest component of the spring ligament complex, which stabilizes the medial longitudinal arch of the foot. This ligament runs obliquely from the calcaneus to the navicular and supports the head of the talus, preventing medial arch collapse.

It plays a critical role in maintaining foot stability, talar support, and arch integrity. Injuries or degeneration of the spring ligament complex often occur in association with posterior tibial tendon dysfunction (PTTD) and are a major cause of adult-acquired flatfoot deformity.

Synonyms

  • Spring ligament (part of complex)

  • Superomedial calcaneonavicular ligament (related structure)

  • Plantar calcaneonavicular ligament (general term for the complex)

Origin, Course, and Insertion

  • Origin: Sustentaculum tali of the calcaneus

  • Course: Runs obliquely in a medioplantar direction, forming part of the hammock-like spring ligament complex beneath the head of the talus

  • Insertion: Medial plantar surface of the navicular bone

Tendon Attachments

  • Forms a supporting sling for the talar head in combination with the superomedial calcaneonavicular ligament

  • Works in synergy with the posterior tibial tendon, deltoid ligament, and plantar fascia to stabilize the medial arch

Relations

  • Superiorly: Head of the talus, which rests on the ligament

  • Inferiorly: Plantar calcaneocuboid region and plantar aponeurosis

  • Medially: Tibialis posterior tendon and deltoid ligament

  • Laterally: Navicular bone articulation with cuneiforms

  • Anteriorly: Plantar surface of navicular

  • Posteriorly: Sustentaculum tali and calcaneus

Function

  • Arch support: Maintains medial longitudinal arch integrity

  • Talar stabilization: Supports the head of the talus, preventing medial displacement

  • Load distribution: Absorbs stress during gait and weight-bearing

  • Synergistic role: Works with tibialis posterior and plantar fascia to prevent arch collapse

Clinical Significance

  • Spring ligament injury/attenuation: Leads to medial arch collapse and adult-acquired flatfoot

  • Association: Frequently seen with posterior tibial tendon dysfunction (PTTD)

  • Symptoms: Medial foot pain, progressive flatfoot, instability

  • Surgical importance: Reconstruction or augmentation may be required in severe flatfoot deformities

  • Imaging role: MRI and CT are critical for assessing ligament integrity and degeneration

MRI Appearance

  • T1-weighted images:

    • Normal ligament: low to intermediate signal intensity (dark band) between calcaneus and navicular

    • Degeneration or partial tear: intermediate hyperintensity and thickening

    • Fat planes around the ligament appear bright, aiding visualization

  • T2-weighted images:

    • Normal ligament: darker than T1, uniform low signal

    • Tear or degeneration: hyperintense linear or diffuse signals within ligament fibers

    • Fluid-sensitive T2 sequences highlight discontinuity, edema, or ligament thickening

  • STIR:

    • Normal: dark low signal

    • Pathology: bright hyperintensity, indicating edema, inflammation, or tear

    • Excellent for detecting subtle partial tears and surrounding soft-tissue edema

  • Proton Density Fat-Saturated (PD FS):

    • Normal: low homogeneous signal

    • Tears/attenuation: bright irregular or diffuse hyperintensity within ligament substance

    • Sensitive to partial fiber disruption and periligamentous fluid

  • T1 Fat-Sat Post-Contrast:

    • Normal: minimal or no enhancement

    • Pathology: enhancement in ligament tears, synovitis, or inflammatory changes

    • Post-surgical cases: scar tissue enhances, while recurrent rupture remains non-enhancing

CT Appearance

Non-Contrast CT:

  • Ligament not clearly delineated (similar density to surrounding soft tissues)

  • Indirect signs of chronic injury: loss of medial arch height, talar head uncovering, calcaneal valgus deformity

  • Degeneration may show as ligament thickening or calcification in advanced cases

Post-Contrast CT (standard):

  • Ligament poorly defined without intra-articular contrast

  • Soft tissue inflammation or adjacent bony changes may be better appreciated

MRI images

Medioplantar oblique calcaneonavicular ligament coronal cross sectional anatomy 3T MRI AI enhanced radiology image-img-00000-00000_00001

MRI images

Medioplantar oblique calcaneonavicular ligament sagittal cross sectional anatomy 3T MRI AI enhanced radiology image-img-00000-00000

MRI images

Medioplantar oblique calcaneonavicular ligament (spring ligament complex) axial cross sectional anatomy 3T MRI AI enhanced radiology image-img-00000-00000