Your browser does not seem to support JavaScript. As a result, your viewing experience will be diminished, and you have been placed in read-only mode.
Please download a browser that supports JavaScript, or enable it if it's disabled (i.e. NoScript).
An instrument for trepanning, being an improvement on thetrepan. It is a circular or cylindrical saw, with a handle like thatof a gimlet, and a little sharp perforator called the center pin.