Cardiac silhouette

Last revised by Frank Gaillard on 28 Jun 2018

Cardiac silhouette refers to the outline of the heart as seen on frontal and lateral chest radiographs and forms part of the cardiomediastinal contour. The size and shape of the cardiac silhouette provide useful clues for underlying disease.

Radiographic features

From the frontal projection, the cardiac silhouette can be divided into right and left borders:

On the lateral projection the cardiac silhouette is formed by 1:

Size

The cardiac silhouette is considered enlarged if the cardiothoracic ratio is greater than 50% on a PA view of the chest 1. See main article: enlargement of the cardiac silhouette for more information.

Shape

The shape of the cardiac silhouette can be used as clues to the underlying disease. For example 1:

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