Coronary SulcusEdit

The coronary sulcus, also known as the atrioventricular groove, is a prominent circular groove on the external surface of the heart that marks the boundary between the atria and the ventricles. It forms a continuous band that encircles the heart, separating the atrial walls from the ventricular walls as the heart contracts and relaxes. The groove serves not only as a clear anatomical landmark but also as a conduit for major vessels and veins that supply and drain the heart muscle. The sulcus can be observed in a variety of imaging modalities, including coronary angiography and cardiac MRI.

Within the circular path of the coronary sulcus lie essential components of the heart’s circulation. The right coronary artery travels along the right portion of the groove, supplying portions of the right atrium and right ventricle, and giving off branches that may participate in the heart’s conductive system in some individuals. On the left side, a portion of the left coronary artery—the circumflex branch—runs in the left atrioventricular portion of the sulcus, distributing blood to the left atrium and portions of the left ventricle. The posterior part of the sulcus houses the coronary sinus, a large venous channel that collects most of the heart’s venous blood and drains into the right atrium. Tributaries such as the great cardiac vein contribute to this drainage system. These relationships make the coronary sulcus a critical anatomical landmark for clinicians and surgeons working with the heart.

Anatomy

Boundaries and orientation

The coronary sulcus forms a crown-like ring around the heart, beginning near the right atrium and continuing posteriorly to encircle the left atrium and ventricle. This contour separates the atrial walls from the ventricular walls on the heart’s surface. For a broader view of the heart’s external landmarks, see the heart.

Right coronary artery along the right atrioventricular segment of the groove.
Circumflex branch of the left coronary artery along the left atrioventricular segment of the groove.
Coronary sinus in the posterior portion, with tributaries such as the great cardiac vein, posterior veins, and other small cardiac veins contributing to venous return. See also coronary sinus.
Possible small perforating branches that connect the arterial and venous networks within the sulcus.
In some individuals, the arterial distribution within the groove can vary with coronary artery dominance, influencing which vessel provides the nodal blood supply. See coronary artery dominance.

Variations

Dominance patterns (right-dominant, left-dominant, or codominant) affect how the arteries within or near the sulcus supply the heart, especially the atrioventricular node. See coronary artery dominance.
The precise courses of the circumflex artery and the right coronary artery within the groove show anatomical variability, which can have practical implications for imaging interpretation and surgical planning. For a broader context, consult anatomical variation and coronary artery literature.

Development and terminology

The term coronary sulcus reflects its role as a coronal boundary between myocardial regions and its continuity around the heart. It is often equated with the atrioventricular groove, and in many anatomical texts the two terms are used interchangeably. For historical naming, see nomenclature in heart anatomy.

Clinical significance

Surgical and interventional relevance

The groove serves as a major surgical landmark during procedures such as coronary artery bypass grafting, where surgeons often identify the right coronary artery and the circumflex branch as they dissect in or around the groove. The proximity to the coronary sinus also guides venous cannulation and retrograde approaches to myocardial protection.
The coronary sinus itself, located in the posterior sulcus, is accessed in certain procedures that require venous cannulation or retrograde cardioplegia. Understanding the sulcus’s layout helps minimize injury to nearby structures during these operations. See cardiac surgery and cardioplegia.

Vascular supply and conduction

The arterial supply within the sulcus contributes to the perfusion of portions of the atria and ventricles, and in many people the AV node receives a significant arterial supply from the right coronary artery coursing in the groove. Variations in this supply can influence susceptibility to ischemia in particular regions during coronary disease.
Because the sulcus is a stable, identifiable landmark, it also aids in diagnostic imaging and catheter-based interventions that aim to map or treat vessels around the heart. See coronary angiography.

Pathology and imaging considerations

While the sulcus itself is not a site of disease, its contained vessels can be affected by atherosclerosis or other coronary pathology. Accurate interpretation of imaging studies that depict the groove and its contents is important for planning revascularization or assessing risk. See cardiovascular disease and medical imaging.

History and nomenclature

The coronary sulcus’s dual label as the coronary sulcus and the atrioventricular groove reflects both its anatomical location and its functional relation to the heart’s atrial and ventricular regions. Early anatomical texts and modern atlases emphasize this structure as a defining feature of the heart’s surface anatomy. For cross-references, see history of anatomy and anatomical terminology.