AbstractUndermining and imbricating the superficial musculoaponeurotic system (SMAS) have been advocated by many recent authors to enhance the results of face lifting procedures. Because all undermining has dangers, we compared in 5 fresh cadavers and 15 patients the immediate operative effects on the labial commissures, buccolabial grooves, submental areas, and cervicomental regions of undermining and imbrication with those of plication without any undermining. Closures were made on both sides and with each technique with the layers pulled to their limit of stretch. We found no significant difference between the two methods in the effects on the areas mentioned.Disproven by this study is the theory that undermining and imbricating of the SMAS by itself will permit, at the time of surgery, greater displacement of esthetically important landmarks than will mere SMAS plication without undermining.