While we're on the subject of injuries

Lets get a little specific...

I had a guy at work tell me he had ROAD RASH so bad you could see his knee cap protruding...

This is incorrect...

by definition, a rash is an eruption or efflorescence on the skin

The key word in that sentence is "on" .
If you have bone showing...

then you have Traumatic injury...it maybe Road Traumatic injury, but it ain't no rash.

Examples:

Rash: 

technically, road rash is more of a scrape then a rash..

Traumatic Road damage is a little more...gruesome:

 Strive to avoid all of the above.