Abstract: A bone cutter for shaping a socket, such as a hip socket, comprising a cutter head located at one end of a rotatably driven shaft and having a hemispherical portion with a hemispherical exterior surface, the hemispherical portion containing a closed hollow chamber, and openings, such as slots, in said hemispherical portion connecting between the exterior surface and the chamber, the trailing portion of each of the openings having a cutting edge raised slightly above the hemispherical surface to move material from the socket into the chamber during rotation of the cutter head, and quick release means for connecting and disconnecting the cutter head and the shaft.

Abstract: A duraguard for a surgical cutting tool consisting of a guard mounting member rotatably mounted within the nose section of the tool housing at two spaced locations and supporting a guard arm extending outwardly along the cutting tool and terminating a protective foot extending over the end of the cutting tool to separate the dura from the skull, the arm and foot being rotatable relative to and about the cutting tool in order to follow curved slots formed by the tool.