does find those prescription drugs in his system. not at very high levels, but they were there. >> let's get answers to those questions. chief medical correspondent and neuro surgeon dr. sanjay gupta here with that. sanjay, what about the injuries of bob saget? >> with these types of injuries, you want to figure out if there is a mechanism of injury you can really identify and also the energy of the force of the injury. so, you know, mechanisms, car accidents, falls, things like that is what we typically think of. but then also how significant? if it was a car accident, how fast was the car going? if it was a fall, how far did he fall? these are things we don't know the answers to, but when you look at these findings, as randi pointed out, these are signi significant. this wasn't a more isolated or casual bump of the head, this was something that involved several different fractures. it takes a lot of force to actually cause these sorts of