My favorite all-time NFL story (though it involves the Steelers and may be aprochyphal):
Jack Lambert, in a pre-season contest with the Cardinals, got his finger stuck between a helmet-to-helmet lick. The finger was a mass of broken and bleeding cartilidge; the bones hadn't just been broken, but pulverized. Half his pinkie was hanging by skin.
He came to the sideline so the trainer could look at it. When told he'd have to come out, Smilin' Jack told the trainer to go ahead and cut it off-- he had nine more.