A steerable device for use as e.g. a guidewire for insertion into a subject's body is disclosed. The device features a single side deflection of a bendable portion located at its distal end by application of a longitudinally-directed force either on an inner pull wire or on said bendable portion. The bendable portion is characterized by the presence of a reinforcement structure on one lateral side and a stress relief portion on the opposed lateral side that, upon actuation of the device, allows single side bending thanks to the physical constriction of the reinforcement structure, limiting the compression of one side of the bendable portion. A system further comprising an actuator, as well as methods for using thereof, are also disclosed.