Do not mistake aorta for the IVC
Mistaking aorta for the inferior vena cava (IVC) is a common pitfall and can potentially lead to patient mismanagement. Always trace the IVC superiorly and make sure it is joining the right atrium. Also, try to look for the hepatic vein-IVC confluence when possible. Following table and figure summarize other key differences between these two vessels.
In the following sonographic image, 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!