Abstract: A catheter stiffener adjustment system including a first member with an outer diameter and having at least three first segments with at least one joint enabling the segments to bend relative to each other, and a second member having an inner diameter defining a passageway through which the first member is movable relative to the second member. The second member has at least three second segments with at least one joint enabling the segments to bend relative to each other. In a first position, the first segments and the second segments are alignable substantially in phase to generate a first flexure condition. In a second position, the first segments and the second segments are alignable substantially out of phase to generate a second, stiffer flexure condition.