Jellyfish sign (ultrasound)

Last revised by Arlene Campos on 10 Feb 2025

The jellyfish sign refers to the sonographic appearance of atelectatic lung "swimming" within a large pleural effusion. The mobility of the lung within pleural fluid implies an absence of lung consolidation and the absence of pleural adhesions 1. It also suggests a transudative pleural effusion; the viscosity of exudative effusions may hamper free lung excursion 2.

See also

Cases and figures

  • Case 1: sonographic pleural effusion
  • Case 2: jellyfish sign
:

Updating… Please wait.

 Unable to process the form. Check for errors and try again.

 Thank you for updating your details.