PS While a human bone, like any other bone can be converted into a tool through usage as a tool - e.g. May I have your femur to thump my drum, it still does not become an artifact unless the conversion into a tool modifies the bone in someway e.g. adding a silver handle to a skull in order to fashion an attractive and unusual (if leaky) drinking cup, or perhaps shattering a bone in order to fashion a needle (TheHermit bows to the ubiquitous Wade) or carving notches in it in order to keep count of ones victims.
TheHermit