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 penetrating end defines a substantially planar dissecting segment and a central rod segment extending from the planar dissecting element. The planar segment of the penetrating end defines atraumatic outer edges which may be arcuate in character. In one embodiment, the distal entry surface of the central rod segment and the atraumatic edges of the planar dissecting segment are at least partially exposed from the nose shield when in the extended position of the obturator sleeve. The obturator sleeve may include a generally tapered nose shield for at least partially accommodating the penetrating end.
