A surgical instrument particularly suited to endoscopic and laparoscopic insertion through a cannula of a trocar into an insufflated body cavity or lumen includes a bending member in an elongate shaft that acts to rotate an end effector about an articulation pivot joint. A proximally directed camming surface (e.g., gear segment, cam recess) aft of a pivotal attachment of the end effector to a proximal frame ground of the elongate shaft interacts with a bending member whose proximal end is ground to the proximal frame ground. Differential fluidic actuators or mechanical cam bars deflect a distal end (e.g., rack, cam point) of the bending member to effect articulation. Thereby, the end effector may act upon tissue that would otherwise be obscured, such as behind an organ. The articulated end effector also advantageously allows an endoscope to be positioned behind the end effector without being blocked by the instrument shaft.