A cannula system is described. The cannula system may be formed of biocompatible materials that are suitable to be sterilized. Accordingly, the cannula system may be reusable for a relatively large number of surgical procedures assuming conventional sterilization techniques are employed after each surgical procedure. Additionally, the cannula system may be provided with an internal valve system disposed in a port portion thereof wherein the valve system may be operable to receive the trocar there through, as well as maintaining insufflation of the body cavity. Furthermore, the cannula system may be provided with a plurality of rib members formed on an external surface of the cannula shaft, wherein the rib members may engage the tissues adjacent the incision, thus maintaining the position of the cannula shaft and reducing and/or lessening relative movement of the cannula shaft.