That is what we call a Bunion. What is a bunion?

http://en.wikipedia.org/wiki/Bunion

From the article, These factors are often considered genetic. Although some experts are convinced that poor fitting footwear is the main cause of bunion formation,[2] other sources concede only that footwear exacerbates the problem caused by the original genetic deformity.[3]

I actually dislike women wearing heels due to several reasons:

1) Restrictive footwear
2) Dangerous (balance and drain grates)
3) In event of emergency, it's a hindrance to run (fire, quake)
4) Backache
5) Deformed toes