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Topic

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Apex of the heart

The apex of the heart is the most inferior, leftward, and anterior part of the heart. It is formed entirely by the left ventricle and lies at the level of the fifth intercostal space, midclavicular line. The apex points downward, forward, and to the left, resting on the diaphragm and separated from the chest wall by lung tissue.

It is externally recognized as the site where the apical impulse (point of maximal impulse, PMI) can be palpated in clinical examination. Internally, the apex corresponds to the tapering end of the left ventricular cavity.

Relations

  • Anteriorly: Left lung and costal cartilages

  • Inferiorly: Diaphragm

  • Posteriorly: Left ventricular chamber

  • Laterally: Pericardium and pleura

The apex is important clinically because displacement of the apical impulse indicates cardiomegaly, left ventricular hypertrophy, or heart failure.

Synonyms

  • Cardiac apex

  • Apical region of left ventricle

  • Apex cordis

Function

  • Represents the terminal portion of the left ventricle, responsible for contraction and ejection of blood into the aorta

  • Provides the site for the apical impulse (PMI) during systole

  • Serves as a landmark for cardiac imaging, echocardiography, and auscultation

  • Important in ventricular function assessment and in diseases such as apical hypertrophic cardiomyopathy

MRI Appearance

T1-weighted images:

  • Myocardium at the apex shows intermediate signal intensity

  • Pericardial fat provides contrast to delineate apical borders

T2-weighted images:

  • Normal apex myocardium is intermediate to low signal

  • Areas of edema (e.g., myocarditis, infarction) appear bright hyperintense

T2 Cine:

  • Demonstrates dynamic contractile motion of the apex

  • Useful for assessing regional wall motion abnormalities (e.g., apical ballooning in Takotsubo cardiomyopathy)

STIR:

  • Highlights myocardial edema or inflammatory changes at the apex as bright signal

  • Useful in detecting acute infarction or myocarditis

T1 Fat-Saturated (Pre-contrast):

  • Myocardium shows intermediate signal contrasting with suppressed pericardial fat

T1 Fat-Saturated Post-Contrast (Gadolinium):

  • Normal myocardium enhances uniformly

  • Pathologies (scar, fibrosis, infarct) show delayed enhancement, often localized at the apex in ischemic disease or apical HCM

MRI Non-Contrast 3D Imaging:

  • Provides volumetric visualization of the left ventricular apex

  • Useful in pre-surgical mapping and congenital anomaly evaluation

CT Appearance

CT Pre-Contrast:

  • Apex appears as a soft-tissue muscular structure at the inferior tip of the heart

  • Useful for identifying calcifications or gross morphological changes

CT Post-Contrast (Cardiac CT):

  • Apex enhances as part of the left ventricle in arterial phase

  • Demonstrates wall thickness, contractility (with cine CT), and pathology such as aneurysms, thrombus, or infarction

  • 3D reconstructions delineate apical morphology in congenital anomalies and cardiomyopathy

CT images

Apex of the heart CT axial image

MRI image

Apex of the heart MRI axial image anatomy image -img-00000-00000