Beaver, when bones heal they actually go thru a period of breaking down damaged bone and then start building new bone. The first new bone laid down is trying to bridge the gap and find the other end, so it is sort of all spread out like a mushroom cap. Once the ends connect that forms a bony structure called a callus. On the rads it looks a lot like a grafting scar on a rosebush, wider than the original bone, but it isn't as strong because it isn't full density yet. As fracture healing progresses that area becomes more dense and narrows. Occassionaly, when the bone ends are too far apart to bridge the callus proceeds to seal the two ends of the broken bone to protect the marrow. That forms a "false Joint" or non-union. Usually as long as the callus is still expanding (exuberant) it is still trying to bridge the gap between the broken bones. Clavicles tend to go this way, thats why most people wind up with a bump on their clavicle when it heals.