The right hemithorax has no lung markings visible. There is a triangular opacity
where the right hilum should be.
PATTERN:
The entire right lung is collapsed and the space is totally filled with air.
If the cause was obstruction of the main bronchus, the air would not be filling
the thorax and there would be opacity, not lucency. The problem is thus in the
pleural space and is not a lung pattern.
DIFFERENTIAL DIAGNOSIS:
The right lung is compressed by air in the pleural space, which could have
originated from a defect in the visceral pleura, often spontaneous, or from
a wound in the chest wall, usually traumatic.
