my wife caught her heel edge at Stowe, going pretty fast on a sort of traverse style trail, bounced the back of her (helmeted) head off the hard pack. I was right behind her and i still cringe when i picture how hard and violent the bounce and whiplash was. THat was at least 6, maybe even 8 years ago now
She is STILL dealing with the neck injury all these years later. tore a muscle that just doesn't want to heal right. Her head was fine, but the "bounce" tore some muscle in her neck, near the top of the collarbone