Video 1 shows the typical A-pattern of the lung image, without respiratory lung sliding or pulsation and without B-lines. This pattern is the representation on the screen of a reflection of the chest wall below the artifact image of the pleural line, without any movement relative to the chest wall.1 The mirror effect represents the well-known reverberation phenomenon due to the interaction of the ultrasound beam with air in the pleural space and is highly suggestive of pneumothorax.2-4 However, other pulmonary conditions, such as atelectasis or pleural adhesions, quite common in lung carcinoma, may share with pneumothorax a motionless lung without B-lines. In the stable patient, detection of a motionless A-pattern in the most dependent chest area needs to be confirmed by looking for a highly specific sign for pneumothorax that is the lung point.3-5 This is the point on the chest where the ultrasonography pattern of the aerated lung (ie, the sliding sign) appears again intermittently with respiration and corresponds to the edge of pneumothorax. When the lung is not totally collapsed, a lung point may be found by moving the probe toward the lateral chest and the lower intercostal spaces. However, in case of hydropneumothorax, the lung point cannot be visualized. Rather, a fluid-air level is detected. This latter is imaged as the interposition between an anechoic space on one side of the scan and the echoic pleural line with the mirror image of the chest wall below it on the other side (Video 2).