A surgical access apparatus includes a housing member and a portal member extending from the housing member and defining a longitudinal axis. The housing member and the portal member define a longitudinal passage therethrough dimensioned to permit passage of an elongated object. A centering mechanism is mounted relative to the housing member. The centering mechanism includes an annular element mounted for rotational movement within the housing member and about the longitudinal axis and first and second arm elements mounted to the annular element and extending radially inwardly relative to the longitudinal axis. The first and second arm elements are each positioned to intersect the longitudinal passage and are adapted to pivot relative to the housing member. The first and second arm elements are operatively connected whereby pivotal movement of the first arm element upon engagement with the elongated object causes the annular element to rotate in response thereto and effect corresponding pivotal movement of the second arm element.