Mulifunction and radial deflection wires (66, 64) extend from a catheter shaft (8) and into a handle (4). The multifunction wire is pulled and pushed longitudinally and is rotated about its axis to change the stiffness of and to laterally deflect the tip portion (12). A curve size manipulator (32) on the handle body (24) moves the multifunction wire longitudinally but does not hinder its rotational movement. Rotation of a lateral deflection manipulator (38) on the handle causes the proximal end (70) of the multifunction wire to rotate about its own axis; the free longitudinal movement of the proximal end is unhindered. Any initial corkscrewing or other deflection of the tip portion can be removed at assembly by rotating the proximal end (68) of the radial deflection wire. The longitudinal movement of the manipulators can be limited by movable stops (120). The longitudinal positions of the abutment faces (126, 128) of the stops preferably change according to their longitudinal (distal or proximal) orientation.