A sheet for covering at least a portion of a mattress that includes a movable first section and a movable second section adjacent to and proximate to the movable first section comprises a first sheet section for covering at least a portion of the movable first section, a second sheet section laterally adjacent to the first sheet section configured to cover at least a portion of the movable second section, wherein the first and second sheet sections are joined together at a sheet junction, a first member projecting laterally from the first sheet section toward the second sheet section and extending up to the sheet junction, and a second member projecting laterally from the second sheet section toward the first sheet section and extending up to the sheet junction, wherein a portion of the first member overlays a portion of the second member proximate the sheet junction.