Accessory navicular

An accessory navicular bone is an accessory bone of the foot that occasionally develops abnormally in front of the ankle towards the inside of the foot. This bone may be present in approximately 2-21% of the general population and is usually asymptomatic. When it is symptomatic, surgery may be necessary.From left to right: Type 1, 2 and 3Lateral projection of type 2Type 2Cornuate navicular boneCornuate navicular boneCornuate navicular boneType 2 on one foot (dark arrow) and type 3 on the other (white arrow) An accessory navicular bone is an accessory bone of the foot that occasionally develops abnormally in front of the ankle towards the inside of the foot. This bone may be present in approximately 2-21% of the general population and is usually asymptomatic. When it is symptomatic, surgery may be necessary. Accessory navicular bone may cause a continuous stretch and stress on the tibialis posterior tendon which can progress to chronic disabling pain and may cause tendon rupture or secondary flat foot deformity, when this occurs this condition is commonly known as accessory navicular syndrome. Other conditions which closely mimic the symptoms of an accessory navicular bone include plantar fasciitis, bunions and heel spurs. The Geist classification divides the accessory navicular bones into three types.