Cushion module for patient interface

A cushion module for a patient interface comprising:

• a chassis portion partially forming a plenum chamber pressurisable to a therapeutic pressure of at least 6cmH2O above ambient air pressure, the chassis portion being sized and structured to receive a flow of air at the therapeutic pressure for breathing by a patient;
• and
• a seal-forming structure connected to the chassis portion, the seal-forming structure partially forming the plenum chamber and being constructed and arranged to form a seal with a region of the patient's face surrounding an entrance to the patient's airways, the seal-forming structure having at least one hole therein such that the flow of air at the therapeutic pressure is delivered to at least an entrance to the patient's nares, the seal-forming structure constructed and arranged to maintain said therapeutic pressure in the plenum chamber throughout the patient's respiratory cycle in use;
• wherein the seal-forming structure comprises:
• a central portion positioned on a posterior side of the seal-forming structure, the central portion configured to contact at least the patient's pronasale, nasal alae and lip superior and to seal in use against at least the patient's pronasale, nasal alae and lip superior;
• a pair of mid-lateral portions on the posterior side of the seal-forming structure, each mid-lateral portion positioned on a respective lateral side of the central portion, each mid-lateral portion having a stiffness greater than a stiffness of the central portion;
• and
• a pair of rigidising portions, each of the rigidising portions extending from the posterior side of the seal-forming structure to an anterior side of the seal-forming structure configured to face away from the patient's face during use, each rigidising portion located on a respective lateral side of the seal-forming structure, and each rigidising portion having a stiffness greater than the stiffness of the mid-lateral portions,
• wherein the seal-forming structure is configured not to engage the bridge of the patient's nose in use and wherein the cushion module is configured to leave the patient's mouth uncovered in use.