third surgical instrument 295 with end effector 295 b disposed in the surgical access port 200 is a third lumen 220 containing a third tubular member 240 and a corresponding third worm wheel 260 and third rigid arm 270 the third worm wheel 260 is oriented on an axis substantially transverse to the longitudinal axis a 1 but also different from the axis along which the first and second worm wheels 160 are disposed the surgical access port 200 is configured such that upon actuation of the worm gear 150 the third worm wheel 260 will rotate about an axis substantially transverse to the longitudinal axis a 1 but different from the axes about which first and second worm wheels 160 rotate and third tubular member 240 and third surgical instrument 295 will articulate in conjunction with the first two tubular members 140 and first two surgical instruments 195 as explained above the operator of the surgical access port 200 can determine the relative spacing of the end effectors 195 b 295 b of the surgical instruments 195 295 with respect to a known point such as the cylindrical member 110 or the longitudinal axis a 1 turning now to fig8 a surgical access port 300 is shown which contains a toothed rack.