Abstract: A seal assembly is provided which includes a housing and resilient first seal means associated with the housing. The first seal means is preferably a gasket having an aperture formed therein for receiving surgical instrumentation adapted to cooperate with a dilating means having an exterior face associated with the housing for dilating the aperture of the gasket. The first seal means and the dilating means are adapted for relative movement therebetween, the first seal means and the dilating means assuming a first position wherein the aperture of the first seal means is spaced from the dilating means and is adapted to receive surgical instrumentation of a first diameter with minimal insertion force, and assuming a second position wherein the aperture of the first seal means is stretched around the exterior face of the dilating means for receiving surgical instrumentation of a second diameter greater than the first diameter with minimal insertion force.