A method of operating a navigation system that can orient the distal end
of a medical device in a selected direction to navigate the medical
device through a network of body lumens in an operating region in a
subject that includes identifying a path through the network of body
lumens in the operating region; displaying a two-dimensional image of the
operating region including the path through the body lumens; determining
at least one location on the path; and operating the navigation system to
orient the distal end of the medical device in a direction substantially
aligned with the path at the at least one location and advancing the
distal end of the medical device.