What Happens

Bunions on the big toe often begin when an abnormal foot motion called excessive pronation transfers weight to the inner edge of the sole of the foot. This and other factors, such as having flatfoot and wearing tight-fitting shoes, can result in too much pressure on the big toe (metatarsophalangeal) joint, causing the big toe to bend in toward the smaller toes.

A bunion can affect the other toes. As a result of the pressure of the big toe moving toward other toes, you may develop:

• Ingrown nails (the toenail begins to grow into the toe).
• Corns or calluses.
• Hammer toes.

A bunion can increase the risk of osteoarthritis in the big toe joint.