"Fractured skull" means that a person's skull has been broken or cracked, which can cause severe head injuries and can be very dangerous. Full definition
He hit his head on a tree stump and fractured his skull in several places. (discovermagazine.com)
crawl at the end is that six months after his release, according to the Associated Press, Kenny was killed when he «fractured his skull when he fell from a 15 - foot wall while taking a shortcut to his brother's house after a dinner with his mother.» (rogerebert.com)
Ornithologists estimate that up to 10 per cent of adult robins die not from starvation or attacks by cats, but from fractured skulls obtained in territorial disputes with others of their kind. (newscientist.com)