An occupant support (20) comprises a frame (34), a mattress region (58), and a combination perimeter element/boom (80) which comprises a coupling (82) connected or connectable to the frame and to a working element (162). The coupling renders the working element positionable in a perimeter element position where the working element borders the mattress region and functions as a perimeter element and a boom position in which the working element is higher than the mattress and functions as a boom. A combination perimeter element/boom (80) comprises a frame (74), a coupling (82) connected or connectable to the frame and to a working element (162) having length, height and width axes. The coupling renders the working element positionable in a perimeter element position where the length and height axes lie in a vertical plane and in a boom position in which the length and height axes lie in a horizontal plane.
