The ribcage was a part of a body containing organs such as the heart and lungs.
Kaleds including Davros had more widely spaced ribcages than humans. (TV: The Stolen Earth [+]) In his youth, Davros saw the ribs of some dead Kaleds melt and look as if they were tentacles due to mutation. (AUDIO: Innocence [+])
An agent of MIAOW once put the barrel of a gun against Fitz Kreiner's ribcage. (PROSE: Mad Dogs and Englishmen)