Central vein

A central vein refers to a major vein close to the center of the circulation, i.e. the heart. It originally referred to those large veins in which the distal tip of a catheter could lie for central venous pressure monitoring. To accurately measure the central venous pressure, which is the pressure within the right atrium, there needs to be no venous valves between the vein and the right atrium. 

The following veins lie central to the most central valves in the venous system and are therefore usually considered to be the true central veins ²:

• venae cavae
  • superior vena cava (SVC)
  • inferior vena cava (IVC)
• brachiocephalic veins
• subclavian veins
• common iliac veins
• external iliac veins

Hence catheters located here are known as central venous catheters, central venous lines, or just central lines.

Terminology

It is important to note that although vessels such as the internal jugular vein (IJV) are commonly used to insert central lines they are not themselves regarded as central veins (see below). Indeed, veins such as the IJV contain valves and therefore cannot be used for central venous pressure monitoring ².

Central vein access

Accessing the central veins directly is usually not feasible due to their anatomic inaccessibility, however several more peripherally located veins are often used to reach the central veins, these are (most commonly used first) ^1,2:

• internal jugular vein
• subclavian vein
• femoral vein
• occasionally axillary vein may also be used as a point of access

Disambiguation

• central vein may also be used as shorthand for the following veins ³:
  • central veins of adrenal gland
  • central veins of liver
  • central vein of retina