Coronary Venous Anatomy
 
The last article was on coronary artery anatomy. During my first year of experience of cardiac CT 5 years ago, while I was working on 4 slice CT scan, venous filling was a major issue for overlap of arterial and venous structures; now, with16 and 64 slice CT scanners that is now no longer an issue.
In spite of that I felt a short overview of Coronary Venous Anatomy is essential.

The venous circulation can be divided into three systems: the coronary sinus and its tributaries, the anterior right ventricular veins, and the thebesian veins.


A) The Coronary Sinus into which drains the large veins (which are important).
The coronary sinus predominantly drains the left ventricle and receives approximately 85 percent of coronary venous blood. It lies within the posterior atrioventricular groove and empties into the right atrium at the lateral border of the triangle of Koch. The crescent-shaped thebesian valve guards the orifice of the coronary sinus. The named tributaries of the coronary sinus include the anterior interventricular vein, which courses parallel to the left anterior descending coronary artery. Adjacent to the bifurcation of the left main stem, the anterior interventricular vein courses leftward in the atrioventricular groove, where it is referred to as the great cardiac vein. It receives blood from the marginal and posterior left ventricular branches before becoming the coronary sinus at the origin of the oblique vein (of Marshall) at the posterior margin of the left atrium. The posterior interventricular vein, or middle cardiac vein, arises at the apex, courses parallel to the posterior descending coronary artery, and extends proximally to the crux. Here, this vein drains either directly into the right atrium or into the coronary sinus just prior to its orifice. The small cardiac vein runs posterior through the right atrioventricular groove.

 
Clcik here for Bigger Picture
Clcik here for Bigger Picture
Clcik here for Bigger Picture
Clcik here for Bigger Picture
 
B) Anterior Cardiac venous systems, which are small veins which drain into right atrium.
The anterior right ventricular veins travel across the right ventricular surface to the right atrioventricular groove, where they either enter directly into the right atrium or coalesce to form the small cardiac vein. As indicated, this vein travels down the right atrioventricular groove, around the acute margin, and enters into the right atrium directly or joins the coronary sinus just proximal to its orifice. A relatively constant vein is right marginal vein that follows the right margin of heart
Clcik here for Bigger Picture
 
C) Thebesian veins
The thebesian veins are small venous tributaries that drain directly into the cardiac chambers. They exist primarily in the right atrium and right ventricle.


The topographic separation does not indicate functional separation, the two-system anastamose freely, particularly at cardiac apex, anterior interventricular groove, and conus pulmonalis. Due to this extensive degree of collateralization amongst these veins and the coronary arteries, and the paucity of valves within coronary veins, enables the use of retrograde coronary sinus cardioplegia for intraoperative myocardial protection.

Coronary venous anatomic mapping may aid in planning of transvenous biventricular pacing lead placement and other invasive procedures. .

Coronary sinus is used as landmark in catheter angiogram for tracing circumflex artery.

Dr. Hemant Telkar