Thumbscrews represent a very insidious form of torture. You weren't likely to die from their use, but they created unendurable agony. The device consisted of three upright metal bars, between which the thumbs were placed. A wooden bar slid down along the metal bars, pressing the thumbs against the bottom. A screw pressed the wood bar downward, crushing the thumbs painfully. The thumbscrews were an elaboration of an earlier device known as the pilliwinks, which could crush all 10 fingers and resembled a nutcracker [source: Parry].
Thumbscrews supposedly originated with the Russian army as a punishment for misbehaving soldiers. A Scottish man brought a set home with him and introduced them to the United Kingdom [Kellaway and Parry].
Up next, a very old and very familiar medieval torture device, plus some variations on a theme.