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Coronary sulcus

The coronary sulcus, also known as the atrioventricular groove, is a prominent surface groove of the heart that encircles it transversely at the junction between the atria and ventricles. It marks the separation of the atrial and ventricular chambers and houses major coronary vessels.

On the anterior aspect, the coronary sulcus contains the right coronary artery (RCA) and the small cardiac vein. On the posterior side, it houses the coronary sinus and the circumflex branch of the left coronary artery (LCx). The groove is partially filled with epicardial fat, which cushions and protects the vessels.

The coronary sulcus is of high clinical relevance as a landmark in imaging, surgery, and electrophysiology. It serves as a guide to the location of the coronary sinus for cardiac resynchronization therapy (CRT) lead placement and is a pathway for major coronary circulation around the heart.

Synonyms

  • Atrioventricular groove

  • Coronary groove

  • Sulcus coronarius

Function

  • Serves as the external landmark separating atria from ventricles

  • Houses major coronary arteries and veins (RCA, LCx, coronary sinus, small cardiac vein)

  • Provides a protected channel for epicardial fat and vessels

  • Acts as a guide for interventional and surgical cardiac procedures

  • Defines anatomical regions in cardiac imaging and electrophysiology

MRI Appearance

T1-weighted images:

  • Coronary sulcus appears as a fat-filled groove between atria and ventricles

  • Enclosed vessels (RCA, LCx, coronary sinus) are seen as signal voids

T2 Cine (Cardiac-gated SSFP):

  • Cine imaging shows coronary sulcus as a bright epicardial fat plane encircling the heart at the atrioventricular junction

  • Coronary vessels appear as dark flow voids running within the groove

  • Useful for assessing chamber motion relative to vessel course

STIR (Short Tau Inversion Recovery):

  • Fat suppression improves visualization of vessels within the sulcus

  • Highlights edema, inflammation, or infiltration involving coronary sinus or vessels

T1 Post-Contrast (Gadolinium-enhanced MRI):

  • Coronary vessels and sinus enhance strongly with contrast

  • Coronary sulcus appears as a fatty channel with enhancing vascular structures

  • Useful for identifying tumor invasion, venous obstruction, or post-surgical changes

MRA (Magnetic Resonance Angiography):

  • Depicts RCA, LCx, and coronary sinus within the coronary sulcus in 3D

  • Essential for mapping coronary anatomy, stenosis, or anomalous courses

CT Appearance

Contrast-Enhanced CT (Cardiac CTA):

  • Coronary sulcus visualized as a groove filled with epicardial fat and enhancing vessels

  • Clearly demonstrates RCA course, LCx artery, and coronary sinus

  • Multiplanar and 3D reconstructions define relationships to atria and ventricles

  • Used in evaluation of coronary artery disease, anomalous vessels, venous anatomy, and surgical planning

CT images

Coronary sulcus anatomy CT axial image -img-00000-00000

MRI image

Coronary sulcus mri axial image