What is cortical thickening that precedes a stress fracture?

There are a lot of confusing things you can see on an MRI report, on an x-ray report or an ultrasound report when you're a runner with pain that you think might be a stress fracture.  One of those findings that may be reported on your medical imaging study is a thing called "cortical thickening." I want to explain what that is so you can better understand it in case you happen to see it on an MRI report, x-ray report or in your doctor's notes. What is cortical thickening that precedes a stress fracture?  Well, that's what we're talking about today on the Doc On The Run Podcast.