Abstract: A surgical retractor can be used in conjunction with an electro-surgical instrument without ensuring against the two coming too close together or touching when the surface of the tip of the retractor is electrically and thermally nonconductive and has a Rockwell C hardness of at least 55. The tip of the retractor may have a metal core which is provided with a hard, electrically insulating surface by sintering a ceramic such as aluminum oxide or zirconium oxide. Instead, the tip can be a piece of ceramic which is mounted onto a broad metal band by means of a short length of metal tubing.

Abstract: A caliper that can be operated with one hand to provide accurate direct readings of dimensions within a surgical incision has a fixed jaw at the end of a shaft and a movable jaw at the end of a tube slidably mounted on the shaft. The slidable tube is normally locked in position, but by pressing a button, the user can release the lock, whereupon a coil spring biases the tube and its jaw toward the fixed jaw until their relative movement is stopped by the object being measured. The user then reads the distance between the jaws by the position of a protuberance on the slidable tube relative to a scale etched in the handle.