Fig. 1(A) Scanning image of the left upper thorax obtained through a rib interspace. Upper, real-time mode. Lower, time-motion mode. Two-dimensional imaging showed a hyperechoic pleural line between two ribs. In time-motion mode, there were multiple horizontal lines over the pleural line and homogenous granular echogenicity below it, referred to as the 'seashore sign' (white arrow). (B) Scanning image of left upper thorax obtained through a rib interspace after inserting the tracheal tube 2 cm deeper. Upper, real-time mode. Lower, time-motion mode. The homogenous granular pattern below the pleural line disappeared and 'lung pulse', regular vertical lines (white striped arrows) synchronized with the heartbeat, appeared.