Venae cordis minimae (also called smallest cardiac veins, venae cardiacae minimae, or Thebesian veins) are minute valveless veins in the walls of all four heart chambers. They are most abundant in the right atrium and least in the left ventricle. They originate inside the myocardium and pass through the endocardial layer to empty directly into the chamber. The openings of the chambers are called the foramina venarum minimarum.

The Thebesian venous network is considered an alternative (secondary) pathway of venous drainage of the myocardium. It is named after German anatomist Adam Christian Thebesius, who described them in a 1708 treatise called Disputatio medica inauguralis de circulo sanguinis in corde.

References

• GPnotebook - "venae cordis minimae"
• Medscape Today; Coronary Venous System