This site is intended for healthcare professionals

Go to /sign-in page

You can view 5 more pages before signing in

Cardiovascular silhouette (radiology)

Last reviewed dd mmm yyyy. Last edited dd mmm yyyy

Authoring team

The cardiovascular silhouette is the radiodensity apparent on a standard PA chest radiograph due to the contrast of the blood-filled heart and great vessels against the surrounding air-filled lungs.

It has prominences on each border which occur in a regular sequence and represent cardiovascular structures:

  • right border, from superior to inferior:
    • superior vena cava
    • right atrium
    • inferior vena cava
  • left border, from superior to inferior:
    • arch of aorta - this prominence is termed the aortic knob
    • pulmonary trunk
    • left auricle
    • left ventricle

Inferiorly, the heart shadow merges with that of the diaphragm.

The overall shape of the cardiovascular silhouette is dependent on the phase of breathing due to the attachments of fibrous pericardium to the diaphragm inferiorly. The pericardium is relatively fixed by the great vessels to the roots of the lungs superiorly, so descent of the diaphragm during inspiration tends to make the silhouette look thinner and longer. Hence, standardly chest films are taken in inspiration. Conversely, the normal variation within the population of the shape of the heart results both in extremes of very thin and broad silhouettes. The former are more common in the obese and pregnant ladies; the latter are more common in thin individuals.

Lateral radiographs reveal a radiolucent space posterior to the heart and anterior to the vertebral column; this is the retrocardiac space. It contains the oesophagus and descending aorta.


Related pages

Create an account to add page annotations

Add information to this page that would be handy to have on hand during a consultation, such as a web address or phone number. This information will always be displayed when you visit this page

The content herein is provided for informational purposes and does not replace the need to apply professional clinical judgement when diagnosing or treating any medical condition. A licensed medical practitioner should be consulted for diagnosis and treatment of any and all medical conditions.

Connect

Copyright 2024 Oxbridge Solutions Limited, a subsidiary of OmniaMed Communications Limited. All rights reserved. Any distribution or duplication of the information contained herein is strictly prohibited. Oxbridge Solutions receives funding from advertising but maintains editorial independence.