flail chest
n.— «The first week was the diciest, with Mr. Corzine, who was in an isolation room for security reasons, using a mechanical ventilator because in one small area the broken ribs were unable to help the lungs expand, creating what is known as a flail chest.» —“In Corzine’s Recovery, Doctors Cite Grit and Luck” by Lawrence K. Altman in Camden, New Jersey Tuscaloosa News (Alabama) May 13, 2007. (source: Double-Tongued Dictionary)
“Flail chest” is pretty standard medical terminology, having been listed in the ICD (International Classification of Diseases) since at least 1979: it is a very obvious condition where a section of ribs are totally separated from the main rib cage (due to being broken at both ends, or detatched from the sternum), causing that portion of the chest to rise and fall in a motion out of sync with the rest of the breathing rhythm.
It’s creepy to look at, and of course pretty life-threatening.