Abstract: A restraint assembly includes an inflator for generating inflation gas. The restraint assembly includes an upper cushion portion and an inflatable stiffening device extending generally longitudinally across a lower edge of the cushion portion for providing longitudinal tension and lateral stability to the restraint assembly. Preferably, the stiffening device is tubular. Also preferably, the restraint assembly includes a tensioning device which at least partially surrounds the stiffening device and places longitudinal tension on the stiffening device when inflated. The tensioning device may take the form of a strap or cord that is spiral-wrapped around the stiffening device. The stiffening device preferably includes an inboard stiffening wall and an outboard stiffening wall. The tensioning device may preferably be zig-zag wrapped back and forth across the outboard wall of the stiffening device for preventing occupant interaction with the tensioning device on the inboard side of the stiffening device.