A device for introduction into a body, the device assuming within the body a predefined shape, the device comprising: an elongated element formed primarily from a plurality of segments sequentially interconnected so as to form an effective hinge between adjacent of the segments; and a substantially straight elongated-element-restricting structure receiving said elongated element in a straightened configuration; wherein the segments and the effective hinges are configured such that: when the elongated element is confined to a substantially straight state, the effective hinges transfer compressive forces from one segment to the next so that the elongated element can be pushed so as to advance along said elongated-element-restricting structure; and when the elongated element is not confined by said elongated-element-restricting structure, each segment is deflected at the effective hinge relative to the next segment until at least one abutment surface of each segment comes into abutment with at least one corresponding abutment surface of the next segment, thereby defining a fully flexed state of the elongated element, the fully flexed state corresponding to a predefined shape of the elongated element, characterized in that said substantially straight elongated-element-restricting structure has a cross-sectional shape fitting closely to the external shape of said elongated element. an elongated element formed primarily from a plurality of segments sequentially interconnected so as to form an effective hinge between adjacent of the segments; and a substantially straight elongated-element-restricting structure receiving said elongated element in a straightened configuration; wherein the segments and the effective hinges are configured such that: when the elongated element is confined to a substantially straight state, the effective hinges transfer compressive forces from one segment to the next so that the elongated element can be pushed so as to advance along said elongated-element-restricting structure; and when the elongated element is not confined by said elongated-element-restricting structure, each segment is deflected at the effective hinge relative to the next segment until at least one abutment surface of each segment comes into abutment with at least one corresponding abutment surface of the next segment, thereby defining a fully flexed state of the elongated element, the fully flexed state corresponding to a predefined shape of the elongated element, characterized in that said substantially straight elongated-element-restricting structure has a cross-sectional shape fitting closely to the external shape of said elongated element. when the elongated element is confined to a substantially straight state, the effective hinges transfer compressive forces from one segment to the next so that the elongated element can be pushed so as to advance along said elongated-element-restricting structure; and when the elongated element is not confined by said elongated-element-restricting structure, each segment is deflected at the effective hinge relative to the next segment until at least one abutment surface of each segment comes into abutment with at least one corresponding abutment surface of the next segment, thereby defining a fully flexed state of the elongated element, the fully flexed state corresponding to a predefined shape of the elongated element, characterized in that said substantially straight elongated-element-restricting structure has a cross-sectional shape fitting closely to the external shape of said elongated element.