A case of an additional right external iliac vein surrounding the right external iliac artery and lacking the right common iliac vein.

A case of an additional right external iliac vein lacking a right common iliac vein was found in an 84-year-old female cadaver during a dissection course at Aichi Medical University in 2014. The findings are reported and discussed from the embryological and clinical viewpoints. The right and left iliac venous systems were macroscopically observed with attention to the homonymous arteries and the inferior vena cava. In this cadaver, a preaortic external iliac vein originated from a right external iliac vein and drained directly into the inferior vena cava. The preaortic and right external iliac veins surrounded the right external iliac artery. In addition, the right internal iliac vein drained into the left common iliac vein, and the right obturator vein drained into the right external iliac vein. Our findings suggested that normal external iliac veins developed from the ventral limb of the iliac venous system in this case. Our case has clinical importance for surgical complications such as hemorrhages in pelvic operations, phlebography, and especially central venous cauterization of the right femoral vein.