While Kerley B lines are the most clinically recognized, the full classification describes three patterns:

"Mr. Harrison in Bed 4—please start IV furosemide. And page cardiology. Those Kerley lines are telling us his heart can’t keep up."

: Thin, horizontal linear opacities, typically 1–2 cm long and less than 1 mm thick.

Kerley B lines were not a disease. They were a physical sign—a map of interstitial edema.

Under normal conditions, these structures are too thin to see. Pathological processes cause fluid accumulation or cellular infiltration. The septa swell, casting distinct shadows on the X-ray. Primary Differential Diagnoses

Kerley B lines are short, thin, horizontal lines visible on a chest X-ray that indicate the thickening of interlobular septa, most commonly due to pulmonary edema . Key Characteristics

This is the most common cause. The lines represent pulmonary venous hypertension forcing fluid into the interstitial spaces.

She glanced back at the image. The lines were quiet, delicate, almost easy to miss. But to her, they screamed as loudly as any siren.

The presence of Kerley B lines demands immediate clinical correlation. They are objective signs of interstitial pulmonary edema.

Administer intravenous loop diuretics (e.g., furosemide) if cardiac failure is suspected.

Accurate identification requires optimal viewing conditions and proper patient positioning. Kerley B Lines Kerley A Lines Peripheral bases Central hilum Length Course Horizontal Radial / Oblique Clinical Context Acute fluid overload Severe/Chronic congestion Visual Checklist for Radiologists Check the costophrenic angles. Look closely at the lateral lung margins. Differentiate from overlying skin folds or rib borders. Assess for concurrent cardiomegaly or pleural effusions. Clinical Implications and Next Steps

The lung anatomy contains connective tissue sheets called interlobular septa. These septa separate pulmonary lobules. They contain lymph capillaries and small veins.