A medical guidewire system comprising a first inner member having a first outer diameter, a second intermediate member having a second outer diameter larger than the first outer diameter, and a third outer member having a third diameter larger than the second outer diameter of the second member. The second member has a longitudinal extending opening to receive the first member for sliding movement with respect to the first member and the third outer member has a longitudinally extending opening to receive the second member for sliding movement with respect to the first and second member. The first member has a first stiffness, the third member has a third stiffness greater than the first stiffness, and the second member is movable to stiffen the guidewire system.