An unusual cause of medial foot pain: The cornuate navicular.

The accessory navicular bone (ANB) is a secondary ossification center of the navicular bone and is rarely observed. Three distinct types of accessory navicular bones have been described. The type III, known as the cornuate navicular, is a rare morphological entity of the accessory navicular bone. We report the case of a patient, 48 years old, who presented with chronic swelling and pain in her left foot. Radiological examination permitted the diagnosis and showed a conflict between the tibial posterior tendon and the cornuate navicular, responsible for the symptoms. Surgical treatment led to symptoms relief.