The venae cordis minimae are a number of small veins in the walls of all of the heart chambers. An alternative name is the Thebesian veins.
They originate within the myocardium and pass deeply through the endocardium of the nearest chamber. Their orifices into the chambers are termed the foramina venarum minimarum.
They are more common within the atria and particularly along the interatrial septum next to the right atrium. As well as returning venous blood, they may pass oxygenated blood to the myocardium.