Transverse Pericardial Sinus

sinus transversus pericardii

The transverse pericardial sinus is a tunnel-like passage within the pericardial cavity that runs behind the aorta and pulmonary trunk and in front of the superior vena cava and atria. It forms because the serous pericardium wraps the arterial great vessels in one sleeve and the veins in another. A finger can be passed through it from one side to the other during surgery.

Anatomical Data

Structure & Supply

Location	Within the pericardial sac, behind the ascending aorta and pulmonary trunk, in front of the superior vena cava and the upper parts of the atria.
Parts	Arterial reflection of serous pericardium (in front) Venous reflection of serous pericardium (behind) Superior aortic recess

Biomechanics

Function & Actions

A space created by pericardial reflections rather than a working structure; it allows the arterial and venous ends of the heart some independent movement.

Clinical Relevance

Clinical Notes

Cardiac surgeons pass a finger, tape or clamp through the transverse sinus to separate and control the aorta and pulmonary trunk, for example before cross-clamping the aorta for bypass. Fluid in its superior recess can mimic enlarged lymph nodes or an aortic dissection on CT, a known imaging pitfall. Its counterpart behind the left atrium is the oblique pericardial sinus.

Pathology

Common Injuries & Conditions

Pericardial Recess Fluid Mimicking Disease

Small amounts of normal or excess pericardial fluid in the sinus recesses can be mistaken for lymphadenopathy or dissection on scans. Recognising its typical position avoids unnecessary investigation.

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