Fissures

Oblique fissures are seen only in lateral view

How to identify left and right oblique fissures

• Right oblique fissure has transverse fissure abutting it.

• Right oblique fissure is more vertical, while the left is slanted posteriorly.

• By recognizing the diaphragm it touches

• Left is posterior to right oblique fissure

All of these findings are not useful when there are alterations due to abnormalities.

Very useful in evaluating for signs of loss of lung volume

• Oblique fissure moves forwards with upper lobe atelectasis

  • The characteristic bowing sign is unique to left upper and lingular atelectasis

  • This does not happen on right as a single lesion cannot give both RUL and RML atelectasis

    • Double lesion sign

• Oblique fissure moves backwards with lower lobe atelectasis

• When the atelectasis is due to mass, you may see S curve of Golden

Fluid in fissure is recognized better in lateral view.

• It has a biconvex appearance