Adjustable backrest

An adjustable backrest for supporting a human back comprising:

• a) a straight spine member;
• b) a lumbar support member projecting from said straight spine member;
• c) an upper back support member projecting from said straight spine member adjacent to said lumbar support member;
• d) a back pad resting on said lumbar support member and said upper back support member for supporting said human back, said back pad including a pair of individually adjustable side support members;
• e) lumbar adjustment means connected to said lumbar support member for adjusting curvature of said lumbar support member relative to said straight spine member to accommodate different sizes and shapes of lower back portions of said human back;
• f) upper back adjustment means connected to said upper back support member for adjusting curvature of said upper back support member relative to said straight spine member to accommodate different sizes and shapes of upper back portions of said human back;
• g) said adjustment means connected to said side support members for independently adjusting curvature of each of said pair of individually adjustable side support members relative to said back pad to accommodate different side contours of said human back;
• h) means connected to said straight spine member and said back pad for providing side-to-side mobility of said back pad to accommodate twisting movement of said human back.