Chest x rays made easy
In the fourth of a five part series, Elizabeth Dick compares collapse and consolidation of the lung and looks at pleural effusions
Collapse of a lobe is caused by proximal Obstruction - for example, by a neoplasm, mucus plug, such as in a postoperative patient, or foreign body, such as in a child. Always mention that you are looking for the cause of the collapse.
When the lobe is not aerated it will lose much of its volume and collapse to a predictable location depending on whether it is an upper, middle, or lower lobe. Figure 1 shows the normal site of the lobes of the lung; figures 2 to 5 and their accompanying line diagrams show where the lobes collapse to. The collapsed lobe itself can be very difficult to see - there may simply be a little extra shadowing on the film. A collapsed lobe is a cause of volume loss; the other cause is a pneumothorax. The signs that should alert you to a collapse are due to the