Turns out Robbie fractured his 3rd and 4th metatarsal on his left foot. They were impacted fractures, which means the bone stem was pushed up into the knob at the end of the bone, and that's where the fractures occurred.
Apparently, if you're going to have a fracture, this is the one to have. It's fairly stabile--the bones won't shift around as they heal.
Dr. Roof, our family physician, explained this by drawing the bones--right on Robbie's foot. "You don't mind if I draw on your foot, do you?" he asked. Robbie didn't.
"Dr. Roof is good. He actually explained it to us," was the verdict.
What does this mean? That Robbie can walk on the boot-cast as soon as his foot doesn't hurt anymore. And he can take the boot-cast off at night after 2 weeks. It's hard to sleep in, Robbie reports, so this will be good.
In six weeks, he'll be boot-cast free.