triangle of koch and opening of the right atrium

What are the openings of the right atrium?

Superior opening – Superior vena cava (SVC),

Inferior opening (floor) – Inferior vena cava (IVC) & Coronary sinus,

Anterior & medial part – Atrioventricular orifice (Tricuspid valve),

Smaller openings – Foraminules (for lesser & anterior cardiac veins).

What does the orifice of the inferior vena cava (IVC) contain?

The valve of the inferior vena cava (of Eustachio).

Where is the coronary sinus orifice located?

Between the IVC orifice and the atrioventricular orifice.

What valve does the coronary sinus orifice contain?

The valve of the coronary sinus (of Thebesius).

Where is the atrioventricular orifice located?

In the anterior and medial part of the right atrium.

What does the atrioventricular orifice connect?

The right atrium to the right ventricle.

What valve does the atrioventricular orifice contain?

The tricuspid valve, which has three cusps.

Where do the lesser & anterior cardiac veins open?

At foraminules in the right atrium.

What is located on the floor of the right atrium?

The Triangle of Koch.

What are the borders of the Triangle of Koch?

Septal cusp of the tricuspid valve,

Orifice of the coronary sinus,

Interatrial septum (where Todaro’s tendon may be found).

Why is the Triangle of Koch important?

It contains the atrioventricular (AV) node under the atrial endocardium.

Where is the AV node located?

Outside the right atrium, in a region called the pyramidal space.