Nasal cannula and securement system

A patient interface comprising:

• a body defining a manifold, the manifold comprising:
• a first opening;
• and
• a second opening, the first opening and the second opening in fluid communication with each other via the manifold;
• a pair of nasal prongs extending from the body, the pair of nasal prongs in fluid communication with each other via the manifold, each nasal prong of the pair of nasal prongs comprising:
• a gas inlet for fluid communication with a supply of breathable gas;
• a gas outlet to direct a flow of gas to a nare of a patient;
• and
• an exterior surface, at least a portion of the exterior surface being a sealing surface configured to seal the nare of the patient;
• and
• a recess between the pair of nasal prongs, the recess configured to avoid contact with a septum of the patient, a wall of the recess being thinner relative to a wall of the pair of nasal prongs.