On an axial CT of the thorax at the level of the pulmonary veins entering the heart, which cardiac chamber forms the posterior border of the heart and lies directly anterior to the oesophagus?
- A Right atrium
- B Right ventricle
- C Left atrium ✓
- D Left ventricle
Correct answer: C. Left atrium
Explanation
The left atrium is the most posterior chamber of the heart and sits immediately in front of the oesophagus, a relationship exploited in transoesophageal echocardiography. The right ventricle forms most of the anterior sternocostal surface, the right atrium forms the right border, and the left ventricle forms the left border and apex. Only the left atrium contacts the oesophagus across the oblique pericardial sinus region.
Reference: Gray's Anatomy for Students, 4th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.