Which of the following does not form right border of heart in the X-ray?
Ans. is 'a' i.e., Pulmonary trunkNormal Heart shadow* In the PA view of chest the transverse diameter of the cardiac shadow is slightly less or equal to half the transverse diameter of chest, i.e., heart: chest ratio is 1 : 2 (=0.5). If this ratio is increased above 0.5, it is suggestive of cardiac enlargement.* The margins of cardiac shadow are identifiable in PA, right anterior oblique (RAO) and left anterior oblique (LAO) views.* In PA view the right margin of heart is formed by superior vena cava, right atrium and inferior vena cava from above downward. The left margin is formed by aortic knuckle (Prominence due to arch of aorta), Pulmonary trunk, left auricle and left ventricle from above downward.* In LAO view the heart shadow is largely made up of right ventricle anteriorly and left ventricle posteriorly. In the RAO view of chest x-ray the heart shadow shows all the four chambers. The posterior border of heart shadow is formed by left atrium, therefore this view is used to assess the size of the left atrium.* Anterior borderAnterior border of heart is formed by (from above downwards): i) Ascending aorta; ii) Pulmonary artery; Hi) Right ventricle* Posterior border Posterior border of heart is formed by (from above downwards): i) Pulmonary artery; ii) Left atrium; iii) Left ventricle.
Pulmonary trunk
Superior vena cava
Right atrium
Inferior vena cava
C.V.S.