Abstract: A medical catheter instrument has a shaft portion, a distal portion bendable in a controlled manner in at least one direction relative to the shaft portion, and a control element extending in an axially movable manner through the shaft portion to the distal portion. The axial movement of the control element controls a corresponding bending movement of the distal portion. The catheter instrument includes a bending assembly having at least one elongated, elastically bendable stiffening element and at least one elongated, bendable and axially length-adjustable bending element, the elements being provided in an axial sub-region of the distal portion and extending therein with an axial main component, wherein the stiffening element forms an element restoring bending movement and has a higher flexural stiffness than the bending element, and the bending element is coupled to the control element or forms part of the same.