An article on the same here:
Misano MotoGP:
I broke the scaphoid below my throttle hand - whilst playing football years ago.
It is a very painful injury & if it doesn't heal properly can require surgery to prevent disruption to the blood circulation to the hand.
Fair credit to the guy if he's prepared to ride a Moto GP bike with a broken scaphoid.
These Moto GP riders are made of stern stuff. Lorenzo, Hopkins & Pedroza seem to be riding with more fractures than they see all day at our local A&E.