Lesson 4

Question 1

What are the 3 systems that make up the venous
drainage of the heart?

Answer 1

• venous tributaries that converge to form the coronary sinus
• anterior cardiac veins
• Thebesian veins.

Question 2

What is the coronary sinus?

Answer 2

• The coronary sinus is the main channel of venous blood coming from the heart’s tissues.
• The coronary sinus opens into
  the right atrium, between the inferior vena cava’s opening and tricuspid annulus.

Question 3

What are the 3 mains veins that converge to form the coronary sinus?

Answer 3

• great cardiac vein
• middle cardiac vein
• small cardiac vein.

Question 4

Describe the location of the great cardiac vein.

Answer 4

The great cardiac vein runs along the anterior interventricular sulcus from the inferior to superior and lies beside the left anterior descending artery. Upon reaching the base of the
heart, it turns and runs along the left atrioventricular sulcus. On the posterior side of the heart, the great cardiac vein becomes the coronary sinus.

Question 5

What is the valve of Vieussens?

Answer 5

The junction where the great
cardiac vein meets the coronary sinus, is a valve called the valve of Vieussens which prevents the
backflow of blood from the coronary sinus into the great cardiac vein.

Question 6

What is the oblique vein of Marshall?

Answer 6

An oblique vein coming from the left atrium, that connects to the great vein and provides drainage from the left atrium.

Question 7

Describe the location of the middle cardiac vein.

Answer 7

The middle cardiac vein arises from the posterior aspect of the apex and runs along the
posterior interventricular sulcus from the inferior to superior and lies beside the right (or
left) posterior descending artery. The middle cardiac vein and its tributaries drain the
posterior left and right ventricles, as well as the interventricular septum.

Question 8

Describe the location of the small cardiac vein.

Answer 8

The small cardiac vein originates from the inferior anterolateral surface of the right
ventricle. It runs along the acute marginal artery and ascends toward the right
atrioventricular sulcus. It then turns toward the posterior side of the heart and enters the
coronary sinus. In some cases, the small cardiac vein drains directly into the right atrium.
The small cardiac vein drains the posterior wall of the right atrium and right ventricle.

Question 9

Describe the location of the anterior cardiac veins.

Answer 9

The anterior cardiac veins are composed of 2-4 branches that travel superiorly to cross the
right atrioventricular sulcus and enter the right atrium directly, draining the anterior wall of
the right ventricle. An acute marginal vein runs beside the acute marginal artery and is
considered part of the anterior cardiac vein.

Question 10

Describe the Thebesian veins.

Answer 10

The Thebesian veins are microscopic vessels that originate from capillary beds and drain directly into the right atrium.