Confusing the aorta with the inferior vena cava (IVC) is a classic POCUS pitfall, often dismissed as a “rookie mistake,” yet not unheard of even among experienced users, particularly when image quality is suboptimal or the patient’s body habitus makes scanning challenging.

The key is to always trace the IVC upward to confirm its continuity with the right atrium. Whenever possible, identify the hepatic vein–IVC junction, a dependable landmark for orientation. Gently fanning the probe to visualize and identify both vessels can further reduce the risk of error.

The table and figures below highlight additional distinguishing features that can help differentiate these two vessels with confidence.

In the following sonographic image (left), the initial vessel is aorta (note anterior branches) and as we fan the probe towards the right, IVC emerges. Hepatic vein joining the IVC can be seen. This image also illustrates how IVC passes ‘through’ the liver while aorta is by the side (= there is some gap between the aorta and the liver).

Here is a nice example showing IVC entering the right atrium (RA). Also note the hepatic vein, tricuspid valve. Occasionally, you may find tricuspid valve vegetation in this view!

Pulsatility should NOT be used to differentiate IVC and aorta. Contrary to popular perception, IVC is often pulsatile, more so in hyperdynamic states (e.g., sepsis, volume depletion, cirrhosis) and tricuspid regurgitation. Below is a nice example demonstrating pulsatile IVC.