A bunion is a firm, painful bump that forms over a bony bulge at the base of the big toe. In most cases, the big toe joint also is enlarged and has degenerative arthritis. The toe also may be pushed toward the second toe (hallux valgus).
Bunions tend to be inherited, but they also are common in the following groups:
Women who wear high heels
People who wear shoes that are too narrow or too pointed
People with flatfeet
All of these situations force the big toe to drift toward the little toes, and this can cause bunions to form.