Symptoms of an Accessory Navicular Bone

An accessory navicular bone is an extra bone that can be found on the inside portion of the foot near the arch. Some people are born with an accessory navicular bone but never develop symptoms, while others experience pain, swelling, and foot dysfunction when the accessory bone irritates surrounding structures (specifically the posterior tibial tendon).

Learning about early symptoms of problems with the accessory navicular bone may allow you to seek treatment before you experience difficulty walking, exercising, or wearing shoes.

Visual Cues

The most obvious symptom of an accessory navicular bone is typically a bump that appears along the arch of your foot. This bump will often become more visible or palpable when you are active or wearing shoes that tightly fit around your midfoot.

Bone Prominence Along Medial Foot Arch

The accessory navicular bone typically causes a rounded prominence to develop along the inside of your foot near the middle section.

Symptoms often include:

• Firm lump along inside arch of foot that can be felt

• Pain when pressure is applied to lump

• Increased pain after standing or walking for long periods of time

The bump is often located in the same area as where the posterior tibial tendon attaches near the accessory navicular bone.

Redness and Swelling

Inflammation is another possible sign that your accessory navicular bone is causing symptoms. Your skin may become irritated from your shoes rubbing along the bone prominence or from repetitive activity.

Symptoms can include:

• Redness along top of bump

• Mild swelling along arch of foot

• Warmth to touch after standing or exercise

Persistent swelling or inflammation along the affected area may require medical treatment if resting and changing shoes does not help. Your posterior tibial tendon may become irritated or inflamed from the accessory navicular bone.

Pain and Discomfort

Typically, symptoms begin along the arch of your foot and may come and go depending on your activity level.

Symptoms can include:

• Dull pain along the inside of your foot

• Occasional sharp pains when active

• Warmth or swelling along the bump

Foot pain may get worse after running, hiking, or standing for extended periods of time.

Throbbing Pain With Activity

You may experience a throbbing pain along the inside portion of your foot when you are active. Running, hiking, or standing for long periods of time will typically stress the posterior tibial tendon more than other activities.

Symptoms may slowly develop as you exercise and feel better with rest.

Sharp Pain With Direct Pressure

Sharp pain is often experienced when you put pressure along your accessory navicular bone.

This can happen when your shoe rubs against the arch of your foot or when you apply pressure to the bump.

Sharp pain can also be recreated when clinicians apply pressure to your foot.

Foot Function

Since the accessory bone is located near the attachment point of the posterior tibial tendon, it can cause alterations in normal foot function.

Symptoms may include:

• Slight shortening of stride on the affected foot

• Mild limping after you have been active for long periods of time

• Shoes wearing unevenly on the inside portion of the midfoot

Foot biomechanics can be affected with time and place extra stress on your knees, hips, or low back.

Flat Feet

Having flat feet is another symptom that is commonly associated with having a symptomatic accessory navicular bone. The posterior tibial tendon typically helps support the arch and an extra bone can make it difficult for this tendon to maintain the medial foot arch.

Symptoms may include:

• Progressive flattening of the arch

• Increased pronation or “rolling in” of the foot

• Midfoot fatigue with prolonged standing

Orthotics or arch supports can help decrease stress through the posterior tibial tendon.

Posterior Tibial Tendon Weakness

Symptoms of irritation along the posterior tibial tendon can cause you to have weakness in this tendon.

Symptoms can include:

• Lack of control with excessive foot pronation

• Pain behind your inner ankle

• Inability to perform a single leg heel raise

Posterior tibial tendon strengthening exercises and orthotics can help restore normal strength.

Treasure Valley Foot & Ankle actively treats many of these symptoms by implementing rehabilitation exercises that focus on improving the strength of your posterior tibial tendon and supporting the arch of your foot.

Activity-Related Irritation

Exercise can often cause pain and inflammation along your accessory navicular bone if it stresses your posterior tibial tendon.

Tight Shoes

If your shoes press along the inside of your foot, you may experience symptoms associated with an accessory navicular bone. You may notice:

• Blisters or calluses along the bump

• Pain that does not go away after changing your shoes

• Increase pain with tight shoes

Wearing shoes with a wider midfoot section and good arch support can help decrease symptoms.

Repetitive Activity

Any type of activity that continually stresses your foot can cause inflammation along the posterior tibial tendon.

Activities that can aggravate symptoms include:

• Running

• Jumping sports

• Hiking

• Increasing mileage or intensity too quickly

If you continue to exercise through pain, you can develop tiny tears in the tendon, which can lead to chronic inflammation.

Doctor’s Evaluation

Your doctor can diagnose a symptomatic accessory navicular bone with a physical exam and imaging studies.

Physical Exam

Your clinician will likely check for:

• Tenderness along the medial portion of your navicular bone

• Range of motion of your foot and ankle joint

• Strength of your posterior tibial tendon

• Pain with single-leg heel raises

Physical examination allows your provider to determine if your accessory navicular bone is causing your posterior tibial tendon pain.

Imaging

X-rays will typically be obtained to confirm the diagnosis. In some cases, an MRI or CT scan may be needed to evaluate the surrounding anatomy.

Your doctor may order the following:

• Weight-bearing foot X-rays to visualize the accessory navicular bone

• MRI to check for inflammation of the posterior tibial tendon or bone marrow edema

• CT scan to provide a more detailed look at the bones in your foot

When to See a Doctor

You should see a doctor if you notice persistent:

• Pain along the arch of your foot

• Swelling or redness along a bone bump on the inside of your foot

• Pain when wearing certain types of shoes

• Flatfoot deformity that continues to get worse over time

• Weakness in your foot

Left untreated, you may develop chronic problems with your posterior tibial tendon.

Symptoms of a painful accessory navicular bone can include an arch bump, sharp pains with activity or pressure along the bump, flatfoot deformity, and pain along the inside of your foot.

Since the accessory bone is located near the posterior tibial tendon, it can cause problems with this tendon and lead to flatfoot deformity. The sooner you treat your symptoms, the better your chances are of restoring normal function to your foot.

Frequently Asked Questions

What is an accessory navicular bone?

An accessory navicular bone is an extra bone that is located on the inside portion of the foot and along the arch.

What are symptoms of an accessory navicular bone?

Some of the most noticeable symptoms of an accessory navicular bone include a bump along the arch of your foot, sharp pain along the bump of your foot, and flatfoot.

Can I exercise with an accessory navicular bone?

You should avoid high-impact activities if you have pain along your accessory navicular bone. Walking should not typically cause any pain if you have an accessory navicular bone.

How do you fix an accessory navicular bone?

Typically, non-operative treatment in the form of rest, ice, orthotics, shoe modifications, and physical therapy is the first line of treatment for relieving pain along an accessory navicular bone. If conservative treatments fail, surgery may be needed to remove the accessory navicular bone.