You may know that the human foot has 26 bones, but would you believe some people
have more? These extra bones are called accessory bones, and are most commonly seen in the hands and feet. You don’t grow extra bones, but you can be born with them.
Some people confuse these extra bones with the sesamoid bones which everyone has under the big toe joint. Accessory bones are often found on the inside and outside edge of the foot.
In fact, the most common ones are: os trigonum (behind the ankle), os tibiale externum (also known as the accessory navicular on the inside of the foot), and os peroneum and os vesalianum (which are both located on the outside aspect of the midfoot). These accessory bones are usually the size of a pea of an almond.
Usually these extra bones are painless and nothing to worry about. Problems may start if the bones become inflamed or rub in your shoes. This is when most people start complaining of pain in the area of the accessory bones. The accessory bones are most often identified on an x-ray and can even be mistaken for a fracture. There have been cases where the bones get in between the joints and cause some people to develop arthritis in their foot.
When should you call a doctor? You should call a podiatrist if you notice a bump on your foot or start experiencing pain. Remember, pain is not normal. Podiatrists are experts at reading foot and ankle x-rays and are well trained to differentiate normal accessory bones from fractures or other abnormalities.
If you do have an extra bone causing you pain, there are many treatment options available to get you comfortable again. Treatment is usually conservative and doesn’t necessarily mean you will end up in the operating room.
Give Kansas City Foot and Ankle a call and make an appointment if you notice or a bump or start experiencing foot pain. You might be surprised to find out that you have an extra bone!