There are a few bones in the human body that are connected only to tendons or are embedded in muscle. These are the sesamoids. Two very small sesamoids (about the size of a kernel of corn) are found in the underside of the forefoot near the great toe – one on the outer side of the foot and the other closer to the middle of the foot.
Sesamoids provide a smooth surface over which the tendons slide, thus increasing the ability of the tendons to transmit muscle forces. The sesamoids in the forefoot also assist with weight-bearing and help elevate the bones of the great toe. Like other bones, sesamoids can fracture. Additionally, the tendons surrounding the sesamoids can become irritated or inflamed. This is called sesamoiditis and is a form of tendonitis, and is common among ballet dancers, runners and baseball catchers.
- Pain under the big toe or on the ball of the foot.
- Swelling and bruising.
- Difficulty and pain in bending and straightening the big toe.
Surgery is usually not required to treat sesamoiditis. Over-the-counter anti-inflammatory medications, as well as rest and ice the sole of your feet, usually relieve the pain. Consult your physician before taking any medications.