An obturator assembly for use in dissection of tissue includes an obturator housing, an obturator member mounted to the obturator housing and an obturator sleeve coaxially mounted about the obturator member and adapted for reciprocal longitudinal movement between a retracted position and an extended position. The obturator member includes an obturator rod and a penetrating end. The obturator sleeve has a nose adjacent the penetrating end. The penetrating end defines outer edges leading toward a distal end surface. The outer edges are at least partially exposed from the nose when in the extended position of the obturator sleeve.