Bone bruise vs stress reaction in a runner

Whenever I speak to a runner who wants to know if they can run with a bone bruise, I get confused. If you were "diagnosed" with a bone bruise, you should be confused, too. A bruise is a very simple thing. You fall down and land on your knee and you get a bruise. You get a bruise because your kneecap crushes the skin against the ground and you get bleeding in the skin that you see as discoloration that we call a bruise. You can't see that in a bone. When you get diagnosed with a bone bruise, you have to think of it in terms of bone injury, like a stress fracture. The continuum of bone injury includes stress response, stress reaction and stress fractures. You have to understand the severity of the bone injury before you can decide whether or not to run.  What is the difference between a bone bruise and a stress reaction in a runner?  Well, that's what we're talking about today on the Doc On The Run Podcast.