What are bunions and what causes them?

Bunions affect the base of the big toe (metatarsal). Because of abnormal forces on the joint the bone starts to deform forming an angle instead of a straight line. This is called hallux valgus.

The exact cause of bunions isn't really known. There may be some heredity involved. Some conditions linked with hallux valgus include flatfeet, arthritis, stroke, and cerebral palsy.

Improper footwear with a narrow space (or toe box) for the toes is a contributing factor. Adding a high heel forces the toes further forward into the toe box adding to the problem. The bone may even grow larger at that point because of the pressure.

Women are affected nine times more often than men. Sandal wearers and people who go barefoot have a much lower rate of bunions. Ballet dancers in pointed shoes are at risk for both hallux valgus and the resulting bunions.