An incrementally adjustable wound retractor, which provides access to a body cavity, includes an inner ring having a diameter greater than the desired diameter of the wound incision, an outer ring having an annular axis and a diameter greater than the desired diameter of the wound incision, and a flexible sleeve disposed in a generally cylindrical form between the inner and outer rings. The outer ring includes first and second circular tubes spaced apart axially with each including a lumen having a rigid, noncompliant split hoop positioned therein. The outer ring may be rolled over itself and around the annular axis to retract the sleeve with sufficient force to stretch the incision to the desired diameter. A gel cap seal may be coupled to the outer ring outside of the biological body to seal the opening produced by the wound retractor between the body cavity and outside the body cavity.