The Inferior and Right Side of the Heart Are NOT the Same
No, the inferior part of the heart is not the same as the right side of the heart—these are distinct anatomical and functional regions that should never be conflated in clinical practice. 1
Anatomical Distinction
The inferior (diaphragmatic) surface of the heart refers to the bottom surface of both ventricles that rests on the diaphragm, while the right side refers to the right-sided cardiac chambers (right atrium and right ventricle) 2.
Key Anatomical Facts:
The inferior wall is primarily part of the LEFT ventricle, not the right ventricle, and is supplied by the right coronary artery in approximately 80% of people or the left circumflex artery in 20% 1, 3
The right ventricle occupies the anterior position of the heart, lying immediately behind the sternum, not the inferior surface 2
In standard echocardiographic views, the inferior wall of the left ventricle includes the basal inferior, mid inferior, and apical inferior segments—all part of the LEFT ventricular anatomy 2
Clinical Implications: Why This Distinction Matters
Electrocardiographic Interpretation:
Inferior leads (II, III, aVF) detect pathology of the inferior LEFT ventricular wall, not the right ventricle 1
ST-segment elevation in leads II, III, and aVF indicates inferior wall myocardial infarction of the left ventricle 1, 4
To assess the right ventricle, you must use right-sided chest leads (V3R, V4R), which are completely different from inferior leads 5, 4
Imaging Orientation:
In the apical four-chamber echocardiographic view, the right ventricle and right atrium appear on the LEFT side of the screen, while the left ventricle and left atrium appear on the right side of the screen 2
The parasternal short axis view obtained by rocking the probe can image from "the apex of the left ventricle inferiorly up to the aortic root superiorly"—demonstrating that inferior refers to the bottom of the LEFT ventricle 2
Common Clinical Pitfall
The most dangerous error is assuming inferior wall MI involves the right ventricle. While proximal right coronary artery occlusion can cause BOTH inferior left ventricular infarction AND right ventricular infarction simultaneously, these are separate events affecting different chambers 1, 4.
When inferior MI is present, you must actively look for right ventricular involvement by recording V3R and V4R leads immediately, as ST elevation in these right-sided leads is transient 5, 4
Right ventricular involvement has critical therapeutic implications (avoid nitrates and preload-reducing agents) that would be missed if you incorrectly assumed "inferior = right side" 4
Anatomical Summary
The heart's spatial organization: