- Who
- Inferior Vena Cava
- What
- 20 millimetre(s)
- Where
- Not Applicable ()
The largest vein in the human body is the inferior vena cava, which carries deoxygenated blood from the lower half of the body back up to the heart. Ultrasound imaging studies have found that the inferior vena cava varies considerably in size from one individual to another, with diameters ranging from 1.2 cm to 3 cm (0.47–1.18 in). The average inferior vena cava diameter for an adult is around 2 cm (0.78 in).
In 1993, a case study was published in the Annals of Vascular Surgery that detailed the case of a patient who strained so hard while on the toilet that they restricted the flow through their inferior vena cava and fainted.
