A catheter system for positioning an instrument within a body that includes a hub defining a lumen therethrough for passage of the instrument toward the body. The catheter system also includes an elongate tubular member defining a lumen therethrough. The lumen of the elongate tubular member is in communication with the lumen of the hub for further passage of the instrument toward the body. The system also includes a slitter member that is coupled to the hub. The slitter member is disposed to slit the elongate tubular member as the elongate tubular member moves relative to the hub.
