A device (10) for navigation within a patient's body, said apparatus comprising a tubular structure having an inner lumen and relatively rigid proximal (15) and distal portions (14) separated by at least one very flexible joint (12) with constant inner diameter and small bending radius. At least one magnetic element (13) is embedded in the distal portion of the device and responsive to externally applied magnetic fields, such that the orientation of distal portion aligns approximately with an externally applied magnetic field (B). The inner lumen of the device allows a flexible medical instrument (17) (e.g. catheter, endoscope, etc.) to be inserted and retracted, such that the flexible medical device is effectively steered in the direction of the lumen's distal section.
