What is an accessory navicular
An accessory navicular is an extra bone or piece of cartilage near the navicular bone on the inner side of the foot and is attached to the posterior tibial tendon. It does not usually cause any pain. The accessory navicular can become irritated by overuse or strain to the posterior tibial tendon that attaches to the accessory navicular. This can cause pain and swelling, known as accessory navicular syndrome. Rest, physical therapy and orthotics are treatments that can reduce symptoms. If there is no improvement, immobilization with a walking boot for 4 to 6 weeks may be considered. Surgical intervention is rarely needed.
About 10% to 15% of people are born with an accessory navicular. About half of the people with accessory navicular have it in both feet.
There are three types of accessory navicular bones with Type 2 being the most common one that can cause symptoms.
The accessory navicular can affect the location where the posterior tibial tendon inserts. This tendon has the job of keeping your foot aligned and helping to maintain an arch. The accessory navicular can be associated with a normal foot posture and alignment, or sometimes with a flatfoot.
Accessory navicular bones typically go unnoticed until adolescence. As a child matures, the accessory navicular calcifies and can become firm. This may cause direct pressure on the skin between the shoe and the accessory navicular. Sometimes, repetitive motion or sudden impact across the cartilage bridge between the accessory navicular and the navicular bone causes inflammation and irritation in the area. The posterior tibial tendon that attaches to the navicular may become irritated and inflamed, resulting in persistent pain in the middle of the arch of the foot.
What are the symptoms of accessory navicular?
Accessory navicular bones most often do not cause symptoms. However, ill-fitting shoes, flat feet, foot and ankle sprains or overuse may contribute to causing symptoms which may include:
- a noticeable bony bump on the inner side of the foot, just above the middle arch
- pain or tenderness in the inner arch of the foot
- swelling and redness around the area of the accessory navicular
- pain when weight is put on the foot, which may cause a limp with walking, running or other weight bearing activities
- pain that is often worse during or after physical activity
- difficulty wearing tight shoes (often need to find wider width shoes)
- irritation from shoes rubbing against the bony bump
- weakness in the foot or ankle if the posterior tibial tendon is involved, which can make inward movement of the foot difficult or painful
Accessory navicular symptoms typically do not get worse with age. Most children and teens who have symptoms caused by an accessory navicular bone will find that the symptoms go away when they finish growing.
How is an accessory navicular diagnosed?
A health-care provider will perform a physical exam of the patient’s foot to diagnose accessory navicular syndrome. The physical exam involves:
- assessing the foot and affected area to look for a bony bump and redness in the navicular region (middle arch region of the foot)
- touching and pressing on the area to assess for tenderness or movement
- assessing the patient’s walking pattern and shoe wear
The patient will also have X-rays taken of the foot. Other types of imaging are rarely needed.
How is an accessory navicular treated?
If the patient is experiencing symptoms from an irritable accessory navicular, initial treatment strategies include:
- Wearing well-fitting wider shoes to minimize direct pressure on the accessory navicular area (middle arch of the foot).
- Placing pads over the accessory navicular bump for extra cushioning in footwear.
- Trying orthotics: either over-the-counter gel inserts or arch supports, or custom orthotics can be made to try to decrease the pressure in the painful area.
- Physical therapy focused on calf stretching, ankle stabilization and strengthening of the foot.
- Rest from activities that make the pain worse such as high-impact sports, along with applying ice and elevating the affected foot.
- Use of a nonsteroidal anti-inflammatory drug (NSAID) medication in the form of over-the-counter oral medication such as ibuprofen (e.g., Advil) or naproxen (e.g., Aleve) or topical creams, for a period of 4 to 6 weeks.
If the initial treatment strategies do not work, then immobilization of the foot in a walking boot for 4 to 6 weeks may be offered. This will help to provide enough rest to the irritated area to reduce symptoms.
If after more than six months of consistent therapy, the initial treatments do not help to reduce symptoms and pain, then surgery may be considered to remove the accessory navicular. This is a day procedure that requires a person to remain in a non-weight bearing cast for 4 to 6 weeks after surgery and to participate in rehabilitation to strengthen and return to functional activities after the cast is removed.
While you cannot prevent having an accessory navicular bone, you can reduce the risk of developing accessory navicular syndrome by wearing supportive well-fitting footwear, avoiding repetitive high-impact activities, maintaining a healthy weight and practicing good foot care.
References
Mosca, V. (2014). Principles and Management of Pediatric Foot and Ankle Deformities and Malformations (1st ed.). Wolters Kluwer Health
Hospital for Special Surgery. (2023, October 17). Accessory Navicular. https://www.hss.edu/health-library/conditions-and-treatments/list/accessory-navicular
Sheth, U., & Kay, R.M. (2026, February 21). Accessory Navicular. Orthobullets. https://www.orthobullets.com/pediatrics/4070/accessory-navicular
Parekh, S.G. (n.d.). The accessory navicular: "I have an extra bone in my foot?" OrthoInfo – American Academy of Orthopaedic Surgeons. https://orthoinfo.aaos.org/en/diseases--conditions/ortho-pinion-accessory-navicular
OrthoKids – Pediatric Orthopaedic Society of North America. (n.d.). Accessory Navicular. https://orthokids.org/conditions/accessory-navicular/