Pericardial or pleural? Find the descending aorta

Answer a. The pericardium wraps the heart in front of the descending aorta. Fluid inside it runs between the heart and the aorta. Pleural fluid lies outside the pericardium, behind the aorta, so it cannot pass in front of it.

Answer d. Fluid behind the descending aorta, which does not pass in front of it, lies in the left pleural space. Scan the left lung base to confirm it and judge its size.

Answer a. The descending thoracic aorta runs down behind the heart. In the parasternal long-axis view it is cut in cross-section and appears as a small round circle behind the left atrium, near the junction of the left atrium and left ventricle. Increase the depth to see it.

Answer b. Epicardial fat sits in front of the heart and often looks grey or dark. Free pericardial fluid collects behind the heart first in a supine patient. A stripe in front only, with nothing behind, is more likely to be fat. Confirm in a second view.

Answer c. These findings support cardiac tamponade, where pressure in the pericardium stops the right heart filling. Tamponade is a clinical diagnosis, and a hypotensive patient with an effusion and these signs needs senior help now. The spine sign belongs to pleural effusion and consolidation.