JVD occurs when the increased pressure of the superior vena cava causes the external jugular vein to bulge. When this happens, it becomes more visible on the right side of a person’s neck.

Anatomy. The (external) jugular vein is located superficially under the skin on both sides of the neck, running in a caudodorsal direction from dorsal aspect of the tympanum to the coelomic cavity.

The external and internal jugular veins are joined by the subclavian vein, which enters the right atrium of the heart as the cranial vena cava (Fig. 1). Figure 1: Dissection of the cranial thorax ...