A patient interface device (8) includes a mask including a interface element (12) structured to engage a portion of the face of a patient and a headgear assembly (14) coupled to the mask. The headgear assembly has a top surface member (28) and a bottom surface member (30) the top surface member being coupled to the bottom surface member to form a fluid delivery housing (20) having an airtight internal chamber (32). The fluid delivery housing is structured to receive a flow of breathing gas from a pressure generating device and is fluidly coupled to the interface element. Also the headgear assembly has a plurality of spaced support members (34) provided within the internal chamber to define a plurality of flow paths through the internal chamber around the support members the support members being structured to support the top surface member relative to bottom surface member and prevent the internal chamber from collapsing.
