Actually I heard that Mansfield being decapitated was an urban legend.
While I've never heard or seen anything debunking it, I do hope you're right...
the infowarrior
She was "scalped" as opposed to being decapitated. All 3 of the front seat occupants of the car she was riding in were killed. Had 3 of her children not been sleeping in the backseat, they might've died as well.
I just read today that the rumor came from the fact her wig was thrown onto the dashboard from the force of the accident.
It is an urban legend, and a false one. Mansfield's wig was thrown clear of the crash, and someone -- either in person or seeing the photos of the crash site, I don't recall -- thought it was still attached to her head.
Actually, I misremembered. She was not decapitated, but did suffer severe head trauma. Snopes.com says "scalped" would be the more accurate term.
(A note on the term urban legend: It does not always equate to "false." Some are completely true, and many more have a nugget of truth but become less and less accurate as they're passed around, like any form of folklore.)