Hydro point sign. B-mode, a convex probe is placed longitudinally at the coronal plane in the posterior axillary line at the right lung base. The left arrow indicates a veiled pneumothorax artefact, and the right arrow shows a contour of the diaphragm. The collapsed lung is marked by the left asterisk, the middle asterisk indicates fluid in the pleural cavity, and the right asterisk shows an echogenic shadow of the rib, which partially covers the liver. A video loop is available as Supplementary File 8.