FIGURE 131.12 A: Normal motion-mode of lung Commonly referred to as “seashore” sign with “waves” and “sand.” B: Pneumothorax, known as the “barcode” sign Pitfalls Lung sliding from the opposing pleura can be a subtle finding and has the potential for misinterpretation by the novice sonographer Additionally, cardiac movement, especially when scanning on the left side of the chest, can sometimes be confused for lung sliding Newer ultrasound machines may have significant postprocessing in order to minimize artifacts and create clearer images This postprocessing can interfere with traditionally described thoracic imaging artifacts and make interpretation more difficult