cardiac vein

noun

: any of the veins returning the blood from the tissues of the heart that open into the right atrium either directly or through the coronary sinus: as

a

: one that begins at the apex of the lower part of the heart, ascends in the sulcus between the ventricles in front, and curves around the heart to the left to join the coronary sinus in back

called also great cardiac vein

b

: one that begins at the apex of the lower part of the heart and ascends along the sulcus between the ventricles in back to join the right extremity of the coronary sinus

called also middle cardiac vein

c

: a vein that drains blood from the back of the atrium and ventricle on the right side of the heart, passes along the coronary sulcus, and empties into the coronary sinus near its opening into the right atrium

called also small cardiac vein