title: Cardiac rotation in left lower lobe collapse. "The flat waist sign".
abstract: Some cases of left lower lobe collapse show slight right anterior oblique rotation of the heart, manifested by loss of the concavity of the left heart border on a perfectly symmetrical posterior-anterior or anterior-posterior projection. This is a useful differential diagnostic sign, because it is not present when the left lower lobe is compressed secondary to left upper lobe emphysema.
mesh_terms: D000328:Adult; D005260:Female; D006321:Heart / Q000000981:diagnostic imaging*; D006801:Humans; D008171:Lung Diseases / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D011012:Pneumomediastinum, Diagnostic; D011859:Radiography