Compliant backrest

A backrest comprising:

• a peripheral frame defining a central opening and comprising a pair of laterally spaced upright members connected with longitudinally spaced upper and lower members;
• and
• a flexible shell comprising opposite sides coupled to the upright members and upper and lower portions coupled to the upper and lower members, wherein the shell comprises:
• first means for providing macro-compliance of the shell relative to the frame;
• and
• second means for providing micro-compliance of the shell of the frame relative to the frame.

A backrest comprising:

• a frame comprising a pair of laterally spaced upright members;
• and
• a flexible shell comprising opposite sides coupled to the upright members, wherein the shell comprises:
• first and second slots extending longitudinally along opposite sides of the shell inboard of locations where the shell is connected to the upright members;
• and
• a plurality of openings arranged between the first and second slots, wherein the plurality of openings comprises a matrix of openings adapted to allow lateral expansion of the shell.