Anatomical and echocardiographic correlations in the normal heart.

Knowledge of the normal intracardiac structures and their variations is essential for interpretation of two-dimensional echocardiography. The anatomical features seen in the standard echocardiographic views have been demonstrated in normal heart specimens. The cardiac chambers and their connections must be identified. Visualisation of the inferior vena caval drainage to the right atrium usually enables its identification. The right ventricle may be distinguished by the more distal attachment of the tricuspid valve compared to the mitral valve and the presence of the moderator band. The pulmonary artery is recognised by its bifurcation, whereas visualisation of the origin of the brachiocephalic arteries or of both coronary arteries from a great artery identifies the aorta. Anatomical variants such as a prominent Eustachian valve of the inferior vena cava in the right atrium and fibromuscular strands or 'heart strings' traversing the left ventricular cavity are frequently visualised on the two-dimensional echocardiograms.