A bed comprises a deck having at least one section that is orientation adjustable about a laterally extending, longitudinally translatable axis and a mattress assembly including at least one volumetrically adjustable element associated with the orientation adjustable deck section. The volumetrically adjustable element is adapted to change the thickness of a portion of the mattress assembly adjacent to the deck section in a direction nonparallel to the orientation of the section and in response to a change in orientation of the deck section.
