Surgical access system

The invention is directed to a surgical access system that provides access to a surgical area while maintaining pneumoperitoneum during laparoscopic surgery. The access system comprises a sheath retractor adapted to dilate a wound stretchable to a desired diameter and a detachable seal adapted to be removable from the sheath retractor. In another aspect, the detachable seal comprising a valve including a plurality of overlapping sheets defining an access channel that extends into communication with the incision in the patient. Each of the overlapping sheets includes a portion of the perimeter that is not fixed to the inner diameter of the ring, which provide open edges defining the access channel.