Small cardiac vein
The small cardiac vein is a vessel located mainly within the posterior aspect of the right coronary sulcus, also referred to as the right atrioventricular groove. This vein contributes to the formation of the greater cardiac venous system, along with the coronary sinus and its tributaries, veins draining the right ventricle and veins draining the atria.
The small cardiac vein contributes to the venous drainage of the external layer of the myocardium of the posterior right atrium and right ventricle.
|Drains from||Small venules of the right and inferior borders of the heart|
|Tributaries||Right marginal vein|
|Drains to||Coronary sinus|
|Drainage area||External layer of the myocardium of the posterior right atrium and right ventricle|
This article will discuss the anatomy and function of the small cardiac vein.
Anatomy and course
The small cardiac vein begins in the distal portion of the anterior aspect of the right coronary sulcus, arising from venules surrounding the junction of the right and inferior borders of the heart. It then courses onto the diaphragmatic surface of the heart within the posterior aspect of the right coronary sulcus, emptying into the arterial end of the coronary sinus. Along its course, the small cardiac vein accompanies the right coronary artery (RCA) within the coronary sulcus as well as the marginal branch of the RCA along the inferior border of the heart. The small cardiac vein sometimes receives the right marginal vein. However, in most individuals, the right marginal vein drains directly into the right atrium.
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Anatomical variations of the small cardiac vein are common. In about 60% of individuals, this vein is either very small or completely absent. Additionally, instead of draining into the coronary sinus, the small cardiac vein drains directly into the right atrium in about 50% of cases.