Kerley's B Lines

They are perpendicular to the pleural surface and extend all the way to the lung edge.

So next time you see a chest X-ray with fine peripheral lines, stop and think: Is that the lung crying out before the flood? If yes, you’ve just spotted one of radiology’s most satisfying signs—and possibly saved a patient from drowning from the inside out.

The septa swell. And suddenly, on a plain chest X-ray, Kerley’s B lines appear. kerley's b lines

Short (1–2 cm), thin (

To identify Kerley B lines on a radiograph, look for specific features: They are perpendicular to the pleural surface and

The characteristic radiological features of Kerley's B lines are:

Fibrosis, sarcoidosis, and certain pneumonias (viral or mycoplasma) can also trigger their appearance. Kerley B vs. Other Septal Lines The septa swell

Kerley also described:

Kerley's B lines can be caused by a variety of conditions, including:

Think of the lung as a sponge. The alveoli (air sacs) are the holes; the connective tissue around them is the sponge’s framework. When left atrial pressure rises—due to heart failure, mitral disease, or fluid overload—fluid first leaks into this interstitial space, not yet into the alveoli. This is .