A nasal mask system, comprising: a cushion assembly (250) including a sealing region having a nose ridge region (252), sides of nose region, corners of nose region (254), and a top lip region (255) adapted to seal around both nares of the patient&rsquo；s nose. The sealing region includes a membrane seal (260) that extends around an entire perimeter of the sealing region. The sides of nose region includes a portion adapted to be positioned and seal along a region adjacent the junction between the nasal greater alar cartilage and the lateral nasal cartilage of the patient&rsquo；s nose. The portion includes a wing or sealing flap (270) that protrudes from an inner edge of the membrane along its inner perimeter.
