An obturator assembly is presented including an obturator housing, an obturator shaft operably connected to the obturator housing and defining a longitudinal axis, and proximal and distal ends, and a penetrating member adjacent the distal end of the obturator shaft. The obturator assembly also includes an instrument retention mechanism mounted on a top portion of the obturator housing and adapted for securing and stabilizing surgical instruments, e.g., endoscopes, inserted into the obturator, thereby permitting visualization of tissue as the tissue is being penetrated by the penetrating member.
