Patient interface and cushion thereof

A patient interface for delivering a flow of air to a patient for treatment of sleep disordered breathing, comprising:

• a plenum chamber pressurisable to a therapeutic pressure of at least 4 cmH2O above ambient air pressure, said plenum chamber including a plenum chamber inlet port sized and structured to receive a flow of air at the therapeutic pressure for breathing by a patient;
• and
• a seal-forming structure constructed and arranged to form a seal with a region of the patient's face surrounding an entrance to the patient's airways, said seal-forming structure having a hole therein such that the flow of air at said 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;
• and
• wherein the seal-forming structure includes a cushion having a plurality of interconnected struts forming a plurality of voids, and
• wherein, in use, when the seal-forming structure is in engagement with the patient's face, the struts are configured to flex thereby altering the size, shape and/or orientation of the voids to allow the cushion to conform to the patient's face.