Various embodiments concern an introducer sheath assembly comprising a tubular sheath member having a deflectable distal end portion and a sheath member lumen, and a handle assembly including a steering mechanism for deflecting the distal end portion of the sheath member. The distal end portion of the sheath member can deflect in different directions along a plane by selective tension in one of two pull wires. The selective tension can be caused by selective proximal or distal axial translation of a shuttle assembly relative to the tubular sheath member. The selective proximal or distal axial translation can be controlled by selective clockwise or counterclockwise rotation of a control knob.