A obstetrical wedge-scissor perforator was popularized by William Smellie in themid-eighteenth century.  Earlier deviceshad both an internal and external cutting edgebut the former was abandoned as it served little useful purpose.  Smellie’s design incorporated a protective shoulder at the base of the blades.  The weakness in the design of such perforatorswas that the handles had to be separated to cutor tearthe tissue and thus might require the use of both hands.