Set 6: pleural effusion

normal example

For some effusions, the fluid can be sneaky and may creep far up the inside of the ribcage, leaving an apparently sharp costophrenic angle. To detect these types of effusions, you need to look carefully at the INSIDE margin of the lateral ribs, where they curve around from front to back. On this image, the yellow indicates the undersurface of several of the left ribs, and the red point is where they start to curve from back to front. Notice that the aerated lung comes right up to each red point. This is a normal case.