Patient interface

A patient interface for treatment of sleep disordered breathing, the patient interface 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;
• 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;
• a positioning and stabilising structure configured to provide a force to hold the seal-forming structure in a therapeutically effective position on the patient's head, the positioning and stabilising structure comprising a strap configured to be arranged, in use, so that an anterior portion of the strap is positioned anterior to the patient's face in use;
• a vent to allow a continuous flow of gases exhaled by the patient from an interior of the plenum chamber to ambient, said vent being configured to maintain the therapeutic pressure in the plenum chamber in use;
• wherein the anterior portion of the strap is shaped to form the plenum chamber;
• wherein the seal-forming structure is formed by or provided to the anterior portion of the strap.