Dictionary.net

Consists of a lever mounted on a handle, and straight throughout its whole length, except at its very end, which is slightly curved, in order that it may be more conveniently put under the portion of bone intended to be elevated. The lever is pierced at various distances from its butt-end with several holes, intended for the reception of a movable screw-peg, fixed on the top of a kind of bridge. This part of the instrument consists of an arch, the ends of which are long, and covered with small pads, and on its centre is the screw-peg already mentioned. By means of these holes the arm of the lever can be lengthened at pleasure.