Thus it is a primary purpose of the access device 34 to form with the incision 32 an access or working channel 34, and to provide a valve or other sealing structure across the working channel 34 in order to maintain the pneumoperitoneum. [0068] An enlarged view of one embodiment of the access device 34 is illustrated in FIG. 2 which also shows the abdominal wall 21 and the incision 32.