Pleura: No significant effusion.

The appearance of these lines usually indicates an underlying pathology:

: Fine, reticular (spiderweb-like) lines that are neither central nor peripheral. They are often considered a superposition of many B lines viewed from the front. Common Causes

Septal lines on a chest X-ray refer to the presence of Kerley B lines, which are a type of radiographic finding.

Septal lines on a chest X-ray, often called , are thin, linear opacities that indicate the thickening of the interlobular septa in the lungs. These septa are thin sheets of connective tissue that separate the functional units of the lung, called secondary pulmonary lobules. While normally invisible on a radiograph, they become prominent when fluid, cells, or fibrous tissue accumulate within them. Types of Septal (Kerley) Lines

Kerley B lines are short, horizontal lines at the lung periphery, typically seen at the costophrenic angles. They represent interstitial edema and are often associated with: