Question

Which structure lies posterior to the transverse pericardial sinus?

• A. Aorta
• B. Pulmonary trunk
• C. SVC
• D. Left atrium

Hint:

Anterior is the great arteries, inferior is the left atrium - what is left for the back?

Answer 1

The Correct Option is C

Step 1: The transverse pericardial sinus is a short passage within the pericardial cavity that lies between the reflections of serous pericardium around the arterial ends (aorta and pulmonary trunk) and the venous ends of the developing heart tube.

Step 2: Its boundaries are: anteriorly the ascending aorta and pulmonary trunk, posteriorly the superior vena cava (SVC), and inferiorly the left atrium.

Step 3: So the structure lying posterior to the transverse sinus is the SVC, matching option (c).

Step 4: The aorta and pulmonary trunk lie anterior to it, and the left atrium lies inferior to it, so those options describe other boundaries and are not correct.