Hi all,
Ok, so you would THINK I'd know the answer to this working in Trauma but I don't. So, I'm coming here to the experts.
I took a nasty fall at Jordan yesterday on my way back to the parking lot. Dumbness on my part was a precipitating factor.:O
Or as my father always tells me "all brains, no common sense" yep, that's me! 
I knew the main trail had about 2-3 inches of ice on it because I had to walk my bike UP the main trail to get to the trail head on the right side, just after the second bridge.
After finishing my ride, I was headed to the parking lot thinking "man, I'm doing pretty good here" and the MTB gods laughed...my bike slid directly out from under me to the right, as I put my left foot down to catch myself it was like a slow motion cartoon. Feet went straight up in the air, landed with a "thud" on my back and my head smacked back HARD off the ice bouncing my head back up and forward. Can you say "whiplash?!" :jawdrop:
Anyhow, as I lay there being SOOOO thankful I had my helmet on correctly, I took it off and checked it. The plastic part is fine, not marked. However, there is a little divot--about .5-1inch and another tiny superficial crack just in the foam area that covers the back of your skull.
So, does this necessitate replacement? I wouldn't think so because they are so small but I just want to make sure.
Sorry if this seems like a dumb question. I'm just really not sure.
Thanks!!