Lung: absent sliding is not enough

Answer b. A lung pulse means the left lung is touching the chest wall, so a pneumothorax is unlikely at those points. The left lung is not ventilating, which fits a tube in the right main bronchus. Check the tube position. A pneumothorax shows no lung pulse. An effusion shows fluid above the diaphragm, not this pattern.

Answer a. The lung point, where sliding and no sliding meet, is the only sign here which confirms pneumothorax. Absent sliding and a barcode sign show no movement, which has other causes such as apnoea and adhesions. A-lines appear in normal lung and in pneumothorax, so they do not separate the two.

Answer b. Free air rises to the least dependent part of the chest, which in a supine patient is the anterior chest. Start there and move laterally to look for a lung point. The lung bases and the mid-axillary line suit fluid, which collects in dependent areas. The supraclavicular fossa gives a small, awkward window.

Answer a. Flat lines all the way down mean nothing moves at the pleural line, the barcode or stratosphere sign. The seashore sign has a grainy pattern below the pleural line and shows sliding. The sinusoid sign and the quad sign describe a pleural effusion.

Answer a. Pleurodesis sticks the two layers of pleura together, so the lung stops sliding even when it touches the chest wall. Absent sliding here does not separate adhesions from a pneumothorax. B-lines or a lung pulse rule out pneumothorax at that spot, and a lung point confirms it. A right main bronchus intubation affects the left lung.