The Collaborative International Dictionary of English v.0.48:

Round-backed \Round"-backed`\, a.
   Having a round back or shoulders; round-shouldered.
   [1913 Webster]

WordNet (r) 3.0 (2006):

round-backed
    adj 1: having the back and shoulders rounded; not erect; "a
           little oldish misshapen stooping woman" [syn: hunched,
           round-backed, round-shouldered, stooped,
           stooping, crooked]