A catheter .has a distal section that includes a spring member having at leasta slot,a rib and a spine for biasing the distal section for deflection within asingle plane.Depending on the plurality and orientation of slot(s), rib(s) and spine(s)s,the distalsection can allow for deflection in two opposing directions while allowingonly limiteddeflection in perpendicular directions to maintain torquability, axial loadingcapabilities,and side force performance.