Figure 2.

C-sign (a) typical C-sign: Extends from the talar dome through the coalition component of the posterior talocalcaneal joint to the sustentaculum, (b) deformed C-sign: Extends from the medial area to the posterior area along the talocalcaneal joint and involves the posterior edge of the posterior talocalcaneal joint. Comparing typical C-sign, deformed C-sign shows protruding bony figure posteriorly (see the arrow)