Pseudo lung sliding

(A) Lung sliding: This image shows lung sliding. There is respirophasic movement of the pleural line. This is caused by movement of the visceral pleural against the parietal pleural surface. It indicates that the two pleural surfaces are apposed to one another (ie, there is no pneumothorax at the site of probe application to the chest wall).
(B) Pseudo lung sliding: This image shows movement of the pleural line that is caused by contraction of the intercostal muscle. There is absence of lung sliding. Forceful contraction of the overlying intercostal muscle may be mis-interpreted as lung sliding. Lung sliding is identified as a to-and-fro movement of the pleural line along the main axis of the pleural line. Pseudo lung sliding does not have the same pattern pattern of movement, but rather tracks with the movement of the adjacent intercostal muscle.