Adjustable width mattress with relief portions

A mattress assembly comprising:

• an inner core assembly including a core portion comprised of a plurality of core bladders, the core portion having a head end and a foot end defining a core longitudinal length;
• a left width adjustment portion comprising a plurality of left width adjustment bladders, the left width adjustment portion extending laterally away from a left side of the core portion;
• a right width adjustment portion comprising a plurality of right width adjustment bladders, the right width adjustment portion extending laterally away from the right side of the core portion;
• the left and right width adjustment portions each having a head end substantially longitudinally aligned with the head end of the core portion and extending footwardly a longitudinal distance less than the core longitudinal length thereby defining left and right relief portions;
• a retainer assembly having a base and a plurality of tubes secured to the base and which slidingly receive the core bladders.