A bed (20) comprises a deck having at least one section (44) that is orientation adjustable about a laterally extending, longitudinally translatable axis (58) and a mattress assembly including at least one volumetrically adjustable element (64) associated with the orientation adjustable deck section. The volumetrically adjustable element is adapted to change the thickness (T) of a portion of the mattress assembly adjacent to the deck section in a direction (D2) nonparallel to the orientation (α) of the section and in response to a change in orientation of the deck section.
