Lung Point Sign
So we discussed how it may be possible to have absence of lung sliding but still not have a pneumothorax in an older patient with COPD or if they’ve had a prior lung procedure. However, if you can see this sign which is known as the lung point sign, its actually the most specific sign for pneumothorax. It shows the point at which the visceral pleura is coming in contact with the chest wall and it can tell you the size of the pneumothorax, as well it tells you exactly where that visceral pleura is coming into contact with the parietal pleura.
One thing to be careful of is the pericardium, which is normal on the left and it can be mistaken for a lung point sign if the pericardium is coming in and out of the field of view when the patient breaths. And this is showing a normal left sided interrogation of the anterior thoracic space and you can see the heart coming up as the lung goes in and out and this is normal.