Unobtrusive interface systems

A patient interface assembly configured to deliver a flow of breathable gas to a patient's airways, the patient interface assembly comprising: a flexible cushion configured to sealingly engage an underside of the patient's nose; a frame removably attached to the flexible cushion; and a positioning and stabilizing structure configured to maintain the flexible cushion in engagement with the underside of the patient's nose, the positioning and stabilizing structure comprising a pair of rigidizers that extend laterally relative to opposite lateral sides of the frame, a rear strap portion and a pair of side strap portions extending anterior to the patient's ears, each of the side strap portions being attached to a corresponding one of the pair of rigidizers, the rigidizers not forming an airflow path for the breathable gas, wherein each rigidizer is made of plastic, is configured to extend across the patient's cheek, has a first end located at a corresponding one of the lateral sides of the frame, and a second end attached to a corresponding one of the side strap portions, wherein each rigidizer comprises a first side configured to face the patient's head and a second side opposite the first side, each rigidizer having a first bend and a second bend, the first bend being between the first end and the second bend, the second bend being between the second end and the first bend, the first bend being concave as viewed from the second side, the second bend being convex as viewed from the second side, wherein each rigidizer is configured so that a fabric layer is positioned between the plastic and the patient's face in use, and wherein the positioning and stabilizing structure provides only a two-point connection to the frame.