Patient interface and respiratory support apparatus

A patient interface for use with a respiratory support apparatus for delivering breathable gases to a patient, the patient interface comprising:

• a cushion at least partially defining an internal cavity, the cushion comprising a pair of opposing cushion side walls and a sealing flange arranged to seal against a face of the patient;
• a gases inlet in fluid communication with the internal cavity;
• and
• a tether;
• wherein the tether extends substantially laterally across the cushion inside the internal cavity between the pair of opposing cushion side walls, the tether being mounted to the pair of opposing cushion side walls;
• wherein the tether is configured to resist laterally outward movement of the pair of opposing cushion side walls;
• and
• wherein the tether and the pair of opposing cushion side walls are configured such that the tether extends across, but is spaced from, an upper lip region of the patient.