An accessory navicular is an extra bone on the inner side of your foot. It’s connected to the bone we call the “navicular,” which helps form the foot’s arch. Most people don’t have an accessory navicular, and you can have one and not know it. But in some people, this extra bone causes problems.
An accessory navicular forms as your foot bones develop. In a normal foot, it’s one of two pieces that eventually fuse to form the navicular. But if these two parts don’t fuse, they become two separate bones. They are connected by fibrous tissue or cartilage. An accessory navicular can cause problems in a few ways. It can be irritated by the constant pulling of a tendon that attaches in the area. It can cause a bump on your instep that can rub against your shoe. And, you can injure your foot and hurt the tissue that connects it to the navicular.
Accessory navicular problems are felt on the inner side of your foot. You may have an irritated, swollen bump on your skin. You may have pain or throbbing in your mid foot and arch. Your foot may hurt more when you are active.
Treatment options depend on your needs. For some people, medications and an arch support may help provide relief from pain. In some cases, immobilization with a walking boot may be recommended. If these options don’t help, you may benefit from surgery, Surgery will usually entail removal of the extra bone. Your healthcare provider can create a plan that’s right for you