When you are seriously injured in battle, you go for the throat.

Prerequisite(s): Sneak attack class feature

Benefit: After any attack reduces your hit points to one-quarter or fewer of their normal total, your opponents are denied their Dexterity bonus to AC against your melee attacks for a number of rounds equal to the number of sneak attack dice you possess. This effect ends if your hit points rise above one-quarter of their normal total.