The Navicular Bone on Foot: Structure, Function, and Common Conditions

Foot pain from the navicular bone is not a common foot complaint. So if you having pain on the inside of your arch keep reading as the pain could be from your navicular bone.

What is the navicular bone?

The foot has over 20 accessory bones that each have different names. These extra bones may cause no problems or they may become painful. Many of these accessory bones are associated with tendons in the foot or ankle. They may be adjacent to the tendon or partially incorporated into the tendon. You may wonder why we are born with these extra bones and the answer is we really don’t know. They just hang out in our feet but sometimes will become problematic.

The navicular bone is a cuboid-shaped bone on the inside medial aspect of the arch of the foot. Midway between the ankle joint and the great toe joint. It has a very important function of being the bone that the posterior tibial tendon attaches to. The posterior tibial tendon starts as a muscle on the inside of the lower leg and as it extends down towards the ankle becomes a tendon.

The tendon attaches to the navicular bone and has the function of stabilizing your arch. Without a fully functioning posterior tibial tendon your arch would become flatter. Adjacent to the insertion of the tendon onto the navicular bone is where the accessory navicular bone lies. The accessory navicular is an extra bone in the arch of the foot.

There are different types of accessory navicular bones. It can be relatively small and lies away from the navicular bone and is in the posterior tibial tendon. It may be large and be partially attached to the navicular bone by cartilage. Or may be part of the navicular bone creating ar larger navicular that appears as a hard prominence on the inside of the arch.

Why does it hurt?

This bone may lie dormant and suddenly become painful for the following reasons.

• Trauma – it may be do to an injury to the foot and ankle such as an ankle sprain.
• Overuse – doing too much of a new activity may increase the potential for pain. As the posterior tibial tendon stabilizes the foot from moving side to side any activities that require this motion may create pain in the area. Examples would be walking or hiking on irregular surfaces or racquet sports.
• Pressure to the area – Any type of shoe gear that puts more pressure can create symptoms as the accessory navicular bone will create a prominence in your arch.
• Flatfeet – A flat foot may be more likely to cause pain in this area as the posterior tibial tendon can be overused to help to support the foot and thereby irritate the accessory navicular bone adjacent to it.

Symptoms of accessory navicular bone?

You’ll have prominence on the inside of your arch. You may have redness over the area, and it will be painful when pressure is applied. Accessory navicular symptoms may also occur from wearing shoes or ski boots that are too tight. This may cause rubbing to the accessory bone. The pain will be very deep and dull.

What will a doctor do to evaluate the condition?

The examination of the foot will demonstrate a painful prominence, with pain to pressure and sometimes redness.
X-rays- These will help to confirm the diagnosis and evaluate which type of presentation you have
MRI scan – This is helpful if a fracture of the navicular bone is suspected or if the tibialis posterior which inserts or is attached to the navicular bone is injured, does it have a tear. MRI can give much more detail then an x-ray.

Treatment options

• Resting in a cam boot especially if the problem is acute.
• Physical therapy– to help strength the muscles thereby pain may be reduced.
• Anti-inflammatories may be useful if used early and when symptoms are minimal.
• Icing and resting may also be useful at an early stage
• Orthotics– custom made inserts may be good for long term relief as they will help support the arch and the tendon.
• Surgery– Surgical excision can be very successful and is recommended after conservative measures fail.

What type of navicular bone presentation you have may predict whether you have a increased chance of needing surgery.

If you think you may have an accessory navicular bone you have the option of seeing a foot and ankle specialist or doctor who is member of American academy of orthopedic. Remember early treatment and evaluation is important to maximize the success of conservative treatments and reduce the chance of surgery.