A seal (40) is disclosed for installation on the proximal end of a trocar (5). The seal is generally cylindrical in shape and has an upper portion (41) and a lower portion (42). The lower portion is formed for mating engagement with the proximal end of the trocar. The upper portion comprises a central hole (43) for insertion of a surgical instrument and a plurality of folds (44) in proximity to the cent hole. The folds allow the central hole to dilate and contract to seat on surgical instruments of varying diameters, and various configurations of folds are disclosed.
