Tarsal and carpal coalitions are developmental anomalies of bone differentiation. Despite being relatively common in general population, they tend to be underdiagnosed.
These conditions may lead to pain and stiffness in the affected extremity and incorrect posture that require medical attention. The radiologist is supposed to be aware of these conditions and their appearance.
On plain radiographs, calcaneo-navicular coalition may be recognized by the "C - sign" or the "anteater nose sign" - but these may not be fully expressed. In such cases, CT or MRI may be advised.
The article is supplemented by case studies from our institution.