Chronic back strain. A survey of 50 incapacitated cases.
D001415:Back; D002908:Chronic Disease; D006801:Humans; D008161:Lumbosacral Region / Q000000981:diagnostic imaging; D008306:Malingering; D008875:Middle Aged; D009787:Occupational Medicine; D011859:Radiography; D013180:Sprains and Strains / Q000000981:diagnostic imaging / Q000523:psychology