Whoa! That's one nasty surprise. Never seen that happen before. It's a good thing that it didn't happen at a worse time, like riding w/traffic at cruising speed.

It's tough for me to tell by the pics.....is that BB spindle secured w/a bolt, or a nut? If it's a nut, then the square taper portion is solid. If it's a bolt-on, then the spindle is hollow for at least the length of the taper, and weakened to the extent of the major thread diameter. OTOH, there are plenty of bolt-on spindles out there. I'm just wondering if this was a factor, or maybe just a defect in material. Does anyone know how common this failure is?

I hope the bruises don't last long................