Tarsal pseudo-coalition--a positional artifact

Pseudo-coalition of the talocalcaneal joint is a positional artifact which is created by either slight abduction or inversion of the foot on the lateral radiograph. This apparent bony bridge is due to overlap of normal structures on opposite sides of the hindfoot. It may be distinguished from a true coalition by the following features: 1) it disappears in a truly lateral radiograph, 2) there is no associated talar spur, and 3) there are no clinical findings of spastic flat foot. In addition, the true medial talocalcaneal bridge requires special views for its demonstration and cannot be seen in a lateral radiograph.