Normal lung and pneumothorax using ultrasound m mode

Both sets of ultrasound pictures above show the m mode images below and standard images above. Panel A shows the appearance of a normal lung segment. In the m mode images, the parietal and visceral pleura are divided by the pleural line. Compare the parietal pleura in panel A, which appears as a series of parallel, non-fluctuating lines ("waves") to the visceral pleura, which appears more granular, like sand ("beach"). The presence of these normal findings, sometimes described as the "seashore sign," rules out pneumothorax in this location. Panel B shows an abnormal lung appearance consistent with pneumothorax. Both above and below the parietal line, only parallel, non-fluctuating lines are seen.