Well, I'm going to add that my DD is the very same way! No joke, she had a dark front tooth for the LOOOONGEST time, from fallling on her face so much. She tended to walk on her toes, and inevitably fell on her face - scrapes on her nose, chin, lips, and the dark tooth where it bled into the pulp. It has gotten better w/ age (she's almost 4 now) but she's got a dark tooth again from something that she did! It's a running joke that when seh comes to me crying we'll say "did you fall A-G-A-I-N???!' She'll start to laugh and say yeah.. unless its really serious that is.. then I won't tease her.
She needs to pay more attention - this is in all things she does, and I'm sure this is why she's so accident prone. She'll walk forward but look backwards.. It's as if she doesnt have that sense of self-preservation that we tend to have.. Weird. But, again it's getting better as she ages, as I can reason with her and seh realizes the faults of her not paying attention.
So, good luck, hold him, urge him to be careful and wait till he grows up :) I can't wait till she learns to drive <ugh> I may refrain from allowing that till she shows much much MUCH improved attention to detail LOL Not kidding.