From the case:
Shmoo sign (annotated image)
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Annotated image showing the Shmoo sign for left ventricular enlargement. The shape of the Shmoo superimposed over the radiograph demonstrates the origin of this sign.
Author: Vincent Tatco
License: CC-NC-BY-SA
Case Discussion
Shmoo sign refers to the configuration of the heart with left ventricular enlargement and dilated aorta on AP chest radiographs. The "Shmoo" is a fictional cartoon creature from Al Capp's Li'l Abner comic strip in the 1940s. The prominent left heart border and dilated aorta correspond to the Shmoo’s body and head, respectively.