A catheter system includes a body, a guide member assembly, an articulation assembly, and a partial sleeve. The guide member assembly extends distally from the body and includes a proximal rigid portion defining a longitudinal axis, a distal flexible portion, and an open distal end. The guide member assembly defines a lumen in communication with the body and the open distal end. The articulation section can flex the distal flexible portion and the open distal end relative to the longitudinal axis between a straight configuration and an articulated configuration. The partial sleeve is disposed within a portion of the lumen defined by the distal flexible portion. The partial sleeve also defines a longitudinally extending gap.