A surgical cutting instrument comprising an outer tube having a peripheral wall and a longitudinal axis. The outer tube has a plurality of openings arranged generally longitudinally along the outer tube. Each of the openings has first and second cutting edges defining portions of the periphery of such openings. An inner cutting member is rotatable within the outer tube. The inner cutting member has at least one cutting edge cooperable with the first and second cutting edges of the openings of the outer tube for cutting material from within the patient with a shearing action.