7.10. The Pericardial Sinuses

A Brief Note on the Pericardial Sinuses

Due to the complex folding process that occurs to the serous pericardial layers during embryonic development, two sinuses are produced near the great vessels, where the visceral and parietal layers become continuous with each other. It’s important to note that the sinuses are not in the pericardial cavity. The two sinuses are called the transverse sinus and the oblique sinus.

The transverse sinus is the hollow area posterior to the pulmonary trunk and the ascending aorta, but anterior to the superior vena cava and the pulmonary veins. The area is shaped like a back-to-front ‘S’.

The oblique sinus is a hollow dead-end area posterior to the heart. It is formed as a space between the pericardial reflections of the four pulmonary veins.