Chest X-Ray PA view - Cardiac Borders

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MCQ 117

Q. Which of the following, per se, does not form Left cardiac border on CXR PA view ?

a. Left atrium
b. Left Ventricle
c. Aortic arch/knob
d. Pulmonary trunk

ANSWER:

Ans : A

The cardiovascular silhouette , or cardiac shadow, is the contour of the heart and great vessels seen on chest radiographs.

Its right border is formed by the SVC, the right atrium, and the IVC. 

Its left border is formed by the aortic arch (which produces the aortic knob ), the pulmonary trunk, the left auricle, and the left ventricle. 

Its inferior border is formed by the right ventricle, and 

the left atrium shows no border.

Please note 

1. Left auricle is Left atrial appendage which is a muscular pouch connected to left atrium.
2. Silhouette sign is a misnomer, it should technically be " Loss of silhouette ".

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