A patient interface device (2 102) is includes a cushion (6 106) and a frame assembly (60 160) coupled to the cushion the frame assembly including a main frame member (4 104) and a stiffening structure (62 162) coupled to the main frame member the stiffening structure having a main arm (64 164) a first Y portion coupled to a first end of the main arm having first and second front branches extending at upward and downward angles respectively from the first end of the main arm and a second Y portion coupled to a second end of the main arm having first and second rear branches extending at upward and downward angles respectively from the second end of the main arm.
