Why is sesamoiditis so serious in a runner?

The sesamoid bones, these two little bones and they sit under the big toe joint and interestingly when I show X-rays to someone like somebody who has a stress fracture almost always the first thing they say is “what are those two things” and they're pointing to the sesamoid  bones. They are also very small and they don't have a great blood supply. So if you get a problem with the sesamoids and you get sesamoiditis, it gets flared up and gets worse and worse and worse. A lot of times it'll turn into a sesamoid stress fracture which is very serious because it can actually crack and break. Today on the Doc On The Run podcast we’re talking about why sesamoiditis is so serious in a runner.