The present invention relates to a nasal mask system, comprising: a cushion assembly (250) including a sealing region having a nose ridge region (252), sides of nose region (253), corners of nose region (254), and a top lip region (255) adapted to seal around both nares of a patient's nose, the sealing region including a membrane seal (260) that extends around an entire perimeter of the sealing region, the sides of nose region including a portion (270) 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's nose, the portion including a wing or sealing flap that protrudes from an edge of the membrane seal along its inner perimeter.
