Earth-heart sign

The earth-heart sign is a newly recognized sign of cardiac compromise that may be seen on chest radiographs of patients with tension pneumomediastinum.

The substantial pressure exerted on the heart by the gas trapped in the mediastinum with subsequent impairment of central venous return and obstruction of diastolic filling may lead to a flattening of the cardiac silhouette resembling the oblate-spheroid morphology of the earth itself (which like many planets assumes this shape due to a combination of rotational and gravitational forces), i.e. the earth-heart sign .