What is Accessory Navicular?

The foot is comprised of a number of different bones. In some patients, an additional piece of bone is seen right next to the navicular bone on the inner aspect of the foot. This lies in close proximity to a tendon called the posterior tibial tendon. This additional piece of bone is called the accessory navicular.

What causes Accessory Navicular?

An accessory navicular is a congenital defect, meaning it is present at birth. It is not very common and is only seen in between 2 to 10 percent of the population. It may run in families.

Symptoms and Diagnosis

In most cases, the patient may have have no symptoms whatsoever. However, sometimes an accessory navicular is usually associated with flat feet. Patients may experience a mild amount of pain, as the bone can protrude out and rub against the footwear. Additional trauma to the foot or excessive activity can cause pain as well.

On examination, there may be swelling and redness over the area of the accessory navicular, and patients may experience pain in the area is touched or pressed on. The best test to diagnose an accessory navicular is an X-ray of the foot. It is clearly seen as an abnormal bony bump that lies close to the navicular bone.

How is Accessory Navicular treated?

In cases where an accessory navicular bone is causing symptoms, treatments may be necessary. These can include simple lifestyle changes such as avoiding activities that can cause pain, wearing appropriate and comfortable footwear, and resting the foot if the pain is severe. Custom orthotics may be necessary to avoid pain and provide comfort. Physical therapy may be useful as well.

If you continue to experience pain despite treatment, surgery may be required to remove the accessory navicular. The procedure is very safe and has a high success rate.