Conventional ultrasonic signs in the lung. (a) The pleural line (black bold arrow) is a roughly horizontal hyper-echoic line between upper and lower ribs, identified by acoustic shadows (white arrow). (b) Lung-sliding is a forward-and-back movement of visceral pleura against parietal pleura in real-time motion. In time-motion mode, it includes motionless parietal tissues over the pleural line and a homogenous granular pattern below it (right image). (c) Comet-tail artifacts (white bold arrows) are hyper-echoic reverberation artifacts arising from the pleural line, laser-beam-like and spreading up to the edge of the screen.