Orifice of the Superior Vena Cava

The ostium of the superior vena cava (ostium venae cavae superioris) is the place where the superior vena cava connects to the right side of the heart. The superior vena cava is one of four veins that drain blood from the head, neck, and upper torso. It collects blood from many organs, including the lungs, brain, eyes, ears, nose and upper body.

The mouth of the superior vena cava is located on the right side of the heart, in the region of the right atrium. Here the vein connects to the wall of the heart and forms a valve that prevents blood from flowing back. This valve is called the tricuspid valve.

The superior vena cava has a length of about 10-15 centimeters and a diameter of about 2-3 centimeters. It passes through the chest and neck, where it passes under the collarbone and enters the right atrium. The superior vena cava collects blood from many organs and tissues, including the brain, lungs, liver, and kidneys.

When blood enters the superior vena cava, it passes through the lungs, where gas exchange occurs. The blood then enters the right atrium, where it mixes with blood from other veins and arteries before entering the right ventricle of the heart.

Thus, the opening of the superior vena cava is an important site in the cardiovascular system where blood is collected and distributed throughout the body.