A case of bilateral formation of common jugular vein by the confluence of the external and internal jugular veins.

The external jugular vein and internal jugular vein are the principal superficial and deep veins of the neck, respectively. The former descends along the lateral aspect of the sternocleidomastoid muscle and typically drains into the subclavian vein, whereas the latter descends through the neck and joins the subclavian vein to form the brachiocephalic vein. Here, we report bilateral anomalies involving the external and internal jugular veins in a 90-year-old Japanese female cadaver. In this case, the external jugular vein drained into the internal jugular vein at the lateral border of the sternocleidomastoid muscle, forming a venous trunk that may be described as a "common jugular" vein. The right and left "common jugular" veins measured 60.1 mm and 40.0 mm in length, respectively, and joined the ipsilateral subclavian veins. Anomalies were also detected in the surrounding veins, including the facial vein draining into the external jugular vein on the right side. Although cases of confluence of the external and internal jugular veins have been recorded with varying frequencies, detailed information about their morphology together with associated veins remains limited. The course of the external jugular vein is clinically important in neck surgery and central venous catheterization, therefore understanding venous anomalies such as those observed in the present case is clinically valuable.