How can you brake your mid arm???

I was in a car accident in 2001. I was driving with my left elbow resting on the windowsill. I got t-boned by a car that hit directly at the driver's side door and the door came in about 18". My elbow went through the glass and I broke my ulna, one of the two bones that goes from the elbow to the wrist. It broke at the proximal end, that is, the elbow. It was a 'greenstick fracture', meaning the bone split like a green twig when you bend it. It needed to be held together with a titanium strap, which is still in there. I had to have an 'emergency' surgery to pull out all the little pieces of glass and piece together all the little pieces of bone.