C sign - talocalcaneal coalition

Lateral X-ray
of a flat foot with C-sign, which is a bony bridge between the talar dome and sustentaculum tali, in combination with a prominent inferior border of the sustentaculum tali. This represents a talocalcaneal coalition, which is an abnormal connection between the talus and calcaneus, and is thought to cause the flat foot deformity.
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The C sign is an important radiological sign which may be seen on a lateral radiograph of the ankle in those with the talocalcaneal subtype of tarsal coalition. It can be seen in both osseous and nonosseous coalition.

Radiographic appearance

A continuous C-shaped arc on a lateral ankle radiograph is formed by the medial outline of the talar dome and posteroinferior aspect of the sustentaculum tali due to their bridging.

Differential diagnosis

Considerations include:

  • subtalar syndesmosis or synchondrosis: CT is helpful in differentiating
  • positional artifact
Siehe auch:
Assoziationen und Differentialdiagnosen zu C-Zeichen Talokalkaneare Koalition:
Talokalkaneare
Koalition
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