An extremely rare bifurcation pattern of the caudal abdominal aorta: case report demonstrated by angiography.

An extremely rare bifurcation pattern at the caudal abdominal aorta was encountered on the pelvic angiography and MR angiography of a male patient. Instead of dividing into two common iliac arteries, the caudal abdominal aorta first gave the right external iliac artery at the level of the last lumbar arteries, then bifurcated into a right internal iliac artery and a left common iliac artery. The median sacral artery originated at this anomalous bifurcation. This high origin of the right external iliac artery and separate branching of these right iliac vessels from the abdominal aorta are important during the interventions in the region. We present the angiography findings and discuss the embryological origin of this unusual and unreported congenital anomaly.