I've still never heard a satisfactory explanation for how in the hell two parts of a bone, broken such that they aren't even touching, can find their way back to each other and heal. My son broke his collar bone, and the hospital sent him home in a sling. When I looked at the x-ray, I couldn't believe that's the correct treatment. But a month or two later and he was good as new. Absolutely blows my mind every time I think of it.