small cardiac vein

The smallest cardiac veins drain directly into the heart chambers.

Additionally, some of the flow through the smallest cardiac veins empty back into the left heart directly.

The openings of smallest cardiac veins (foramina venarum minimarum or foramina Thebesii) are located in the heart.

These include the great cardiac vein, the middle cardiac vein, the small cardiac vein and the anterior cardiac veins.

The small cardiac vein runs in the coronary sulcus between the right atrium and ventricle and opens into the right extremity of the coronary sinus.

Here the smallest cardiac veins returns blood into the heart chambers from the capillary bed in the muscular cardiac wall, enabling a form of collateral circulation unique to the heart.

The right marginal vein ascends along the right margin of the heart and joins the small cardiac vein (sometimes known as the right coronary vein) in the coronary sulcus, or opens directly into the right atrium.

The smallest cardiac veins or Thebesian veins or veins of Thebesius are minute valveless veins in the walls of all four heart chambers and they are often confused with the distinct set of arterial connections, the "vessels of Wearn".