Fig. 2

a Diaphragm dysfunction with atypical or paradoxical movement due to large pleural effusion (PE). Red dot line delineates the abnormally shaped diaphragm. Yellow and blue arrows indicate the reverse movement during inspiration. Note that when this sign is present, pleural fluid should be evacuated immediately. b Large pleural effusion (PE) and ascites. The blue arrow indicates the three-layer structure of the diaphragm floating in the fluid: a during expiration; b during inspiration, with abnormal shape; and c during deep inspiration, with the abnormal shape indicating paradoxical movement