It is a extra piece of bone at anteromedial part of ankle, attached with inner planter part of navicular bone.

• This bone is present approximately 2.5% of general population and usually asymptomatic. In early childhood it remains unnoticed. During adolescence when it starts calcify then only get noticed.

You will feel a prominent bony bump at antero-inferior part of ankle. Most of the time its only painless. This may become painful following a twist or injury. A very big bump may develop sensitive skin due to rubbing within shoe.

You should visit a orthopaedic or a specialist foot and ankle surgeon if you develop sensitive skin and pain at this area.

Your doctor will conduct a proper clinical examination which will include checking the status tibialis posterior muscle; responsible for maintaining foot arch. You may ask to get an x-ray of your feet in standing position. If indicated a MRI may also be required.

To start with conservative treatment in the form of NSAID, cold pack is helpful. In case of significant symptom immobilisation may require. Local infiltration of steroid is also practised, but there is difference of opinion. In restrained cases excision of the accessory navicular followed by reattachment of tibialis posterior tendon is required.