Corpus: Vena cava

The vena cava refers to the two largest veins in the human body, responsible for returning deoxygenated blood to the heart.

The vena cava has two parts:

• The superior vena cava, which drains blood from the upper body.
• The inferior vena cava, which drains blood from the lower body.

The vena cava is the largest vein in the human body, with a diameter of approximately 2 cm. Its cross-section and intravascular fluid volume vary depending on body position.

The inferior vena cava develops during the embryonic period from the fusion of the paired subcardinal veins. This process can result in anatomical variations. One common variant is a left-sided inferior vena cava, which may drain into the hemiazygos vein.

The pressure within the vena cava, known as central venous pressure (CVP), typically ranges from 0 to 15 mm Hg. CVP fluctuates with respiration and heartbeats, resulting in the "venous pulse."

Catheters can be inserted into the right atrium via the vena cava for clinical purposes, such as measuring CVP or administering infusion therapy.