Could an Accessory Navicular Be the Hidden Cause of Your Arch Pain?

By Adrian Bianco|2026-07-31T11:59:56+00:00July 31st, 2026|

If you’ve been dealing with persistent pain along the inside of your foot, just above the arch, an accessory navicular could be playing a bigger role than you realise. An accessory navicular is an extra piece of bone that some people are born with on the inside of the foot, just above the arch. It occurs in around 10–20% of the population, although most people never experience symptoms or even know it’s there. For some, however, this small anatomical difference can become painful because of its close relationship with one of the foot’s most important tendons.

Why does an accessory navicular cause pain?

The posterior tibial tendon is one of the main structures responsible for supporting your arch.

In many people with an accessory navicular, the posterior tibial tendon attaches to the extra bone rather than the main navicular bone. Because the accessory bone is connected by cartilage instead of solid bone, it can move slightly under load. Although this movement is minimal, it can repeatedly stress both the tendon and the tissue connecting the two bones.

Over time, this can lead to irritation, inflammation and ongoing pain. In many cases, it’s not just the accessory bone causing the problem—it’s the extra strain placed on the posterior tibial tendon.

What does it feel like?

People with a symptomatic accessory navicular often experience:

A dull ache or sharp pain along the inside of the foot, usually over the bony prominence above the arch.
Localised swelling.
Discomfort when wearing shoes that rub against the area.
Tenderness when pressure is applied.
Flat feet or excessive pronation.
Symptoms that worsen after exercise or prolonged time on their feet.

Because these symptoms closely resemble posterior tibial tendon injuries, it’s important not to assume the tendon alone is responsible. An accessory navicular is often the underlying reason the tendon continues to become irritated.

How is it diagnosed?

A podiatrist can examine your foot, gait and identify the location of your paint to help determine whether an accessory navicular is contributing to your symptoms.

X-rays can confirm the presence of the accessory bone, and MRI scans can identify inflammation within both the accessory navicular and the tendon, helping guide the most appropriate treatment.

How is it treated?

Most cases respond well to conservative treatment, which may include:

Temporary modification of aggravating activities.
Supportive footwear.
Custom foot orthotics to reduce stress on the posterior tibial tendon.
Short-term immobilisation in a walking boot during severe flare-ups.
A rehabilitation program including strengthening and stretching exercises.

If symptoms persist despite appropriate conservative care, surgery may be considered. This usually involves removing the accessory navicular and securely reattaching the posterior tibial tendon to the main navicular bone.

Don’t ignore ongoing arch pain

Pain on the inside of your foot isn’t something you simply have to live with. If you’ve been told you have posterior tibial tendonitis, or you’ve noticed a painful bump above your arch that won’t settle, an accessory navicular could be the missing piece of the puzzle.

An accurate diagnosis is the key to successful treatment. By addressing both the irritated tendon and the underlying mechanical cause, most people can return to walking, exercising and living comfortably without ongoing pain.

Our Melbourne podiatrists have extensive experience assessing and managing accessory navicular syndrome and posterior tibial tendon injuries. If this sounds like what you’re experiencing, we’d be happy to help. Book an appointment today and take the first step towards getting back on your feet.