Purpose or Case Report: The structure of the heart is more complex than 4 major chambers, 4 major valves, venous inflow and arterial outflow.

Muscular and soft tissue ridges, perforated membranes, tissue flaps, electrical pathways, external grooves, endocardial surface characteristics, and a core architecture structured of fibrous tissue and embryonic tissue remnants form distinguishing anatomic landmarks. These structures provide insight into cardiac development, serve physiologic purpose, define structural and functional elements, as well as offer prognostic information.

Specific details of cardiac anatomy may not be recognized on cardiac MR and CT examinations. Structural anomalies that affect cardiac function and anatomic or physiologic relationships may be abnormal in hearts with congenital malformations. The fine structural details of the heart are typically not part of an imagers search pattern and are therefore overlooked or underreported. Each minute structure and anatomic characteristic provides clues to errors in cardiac formation and may provide clinically relevant diagnostic information. After palliation of CHD defining anatomic structure may be lost, displaced, interrupted or even restored.

Important processes, corresponding anatomic landmarks, and effects of malformation in defining congenital heart disease anatomy, physiology and functional variation from normal include basal structures such as the central fibrous body of the heart, atrial structures including the crista terminalis, the sinus venarum, and eustacian valve, and ventricular structures such as the crista supraventricularis.

Each structure is described along with its normal location, anatomy functional and physiologic importance, the effect of congenital malformation, and imaging findings as in the example of the central fibrous body (table 1).

Minute cardiac anatomy will be shown in illustration as well as in CT and MR images (figure 1).
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