Learning Radiology xray montage

Talar Beak
Tarsal Coalition

General Considerations

  • Rare (1% incidence)
  • Fusion of two or more tarsal bones in the hindfoot (talus and calcaneous) or midfoot (cuboid, navicular and 3 cuneiforms)
  • Most common coalitions (90% of total) are
    • Calcaneous and navicular (calcaneonavicular)
    • Calcaneous and talus (talonavicular)
  • Fusion may be congenital or acquired
    • Congenital form is familial
      • Autosomal dominant with near complete penetrance
      • Bilateral 50% of time
      • More common in males than females
    • Acquired form may be due to trauma, infection, arthritis, surgery


  • Complete coalition
    • Bony (synostosis)
  • Incomplete coalition
    • Cartilaginous (synchondrosis)
    • Fibrous (syndesmosis)

Clinical Findings

  • Most are asymptomatic
  • When symptomatic, symptoms begin in 2nd decade of life
  • Pain is most common symptom
    • Made worse by physical activity
  • Restricted range of motion
  • Muscles spasms

Imaging Findings

  • Conventional radiography of the foot is the study of first choice
  • Calcaneonavicular fusions should all be evident on a 45° internal oblique view
    • Bridge is usually from anterolateral aspect of calcaneous to dorsolateral aspect of navicular
  • With fibrous and cartilaginous coalition, the joints may be narrowed, sclerotic and irregular
  • Talocalcaneal coalition may be more difficult to see
    • Most often involves junction between the middle facet of the talus and the sustentaculum talus
    • Talar beak presumably occurs because of limitation of motion in subtalar joint
      • At insertion of talonavicular ligament, periosteal reaction develops
      • Beak not present in all patients with talocalcaneal coalition
  • Pes planus deformity is common
  • Hypoplasia of the sustentaculum tali may occur
  • MRI is most sensitive to fibrous and cartilaginous fusion


  • Conservative treatment is utilized first
    • NSAID (non-steroidal anti-inflammatory drugs)
    • Steroid injections
    • Orthotics
  • Surgical interventions most commonly involve resection of the bridge and placement of fat, muscle or tendon in place of the coalition
  • Arthrodesis is sometimes used with severe coalitions


  • Cause of spastic peroneal flatfoot
  • Bony bridge can fracture

Talar Beak and Tarsal Coalition. The white arrow points to a "talar beak" seen on the dorsum of the talus which should raise suspicion for the presence of a tarsal coalition. The oblique view of the same foot demonstrates bony bridging between the tarsal navicular and the calcaneous.
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Tarsal Coalition  eMedicine Eric A Wang, MD, Amilcare Gentili, MD, Sulabha Masih, MD,  and Matthew C Wang, BS