What Happened?

I have quite a few scars, and I can account for most of them, lots from chicken pox as a kid and lots from fights with my older sister who had long nails. I even have one from when I rolled a go-kart and another from when I broke my finger and the bone poked out. I have a big one on my shin from when I ran in to the ball hitch on my old car, (do you remember that kim?). But I have one fairly substantial scar above my elbow that I have no idea where it came from....Like anybody even remotly cares to know this info, but I rediscovered it today and that was my big thought of the day, what happened?