Symmetrical variations in the branching pattern of abdominal aorta: a case report

Introduction Information regarding anatomical variations in the branching pattern of great vessels of the abdomen, including abdominal aorta, celiac trunk, mesenteric and renal arteries is imperative for planning surgical procedures and interpreting interventional radiological imaging. In fact, liver and kidney transplantations and oncologic resections require major vessels ligation. Background knowledge of the possible vascular variations in the branching pattern of aorta could prove to be life saving during such procedures [1]. The abdominal aorta continues from thoracic aorta at the median aortic hiatus in the diaphragm, at the level of lower border of 12th thoracic vertebra. Classically, 3 ventral branches –celiac trunk, superior mesenteric artery and inferior mesenteric artery– arise from it and supply foregut, midgut and the hindgut, respectively. The first ventral branch, the celiac trunk arises at T12-L1 level. The second and third ventral branches are the superior mesenteric and inferior mesenteric arteries, which usually originate at L1 and L3 vertebral levels, respectively. The lateral branches of the aorta, i.e. renal arteries and gonadal vessels supply the urogenital system. The posterolateral branches –inferior phrenic arteries and the lumbar arteries– supply the body wall, inferior aspect of the diaphragm and posterior abdominal wall [2]. The celiac trunk is about 1.25 cm long, passes almost horizontally forwards. It divides into left gastric, common hepatic and splenic arteries. However, variations in this branching pattern have been reported. It may also give off one or more of the inferior phrenic arteries. Classically, renal artery arises from each side of the abdominal aorta. Renal artery variations are divided into 2 groups: early division and extra renal arteries (ERA). Branching of the main renal arteries into segmental branches more proximally than the renal hilar level, is called early division. ERAs are divided into 2 groups: hilar (accessory) and polar (aberrant) arteries. Hilar arteries enter kidneys from the hilum with the main renal artery, whereas polar arteries enter kidneys directly from the capsule outside the hilum [3]. The frequency of ERAs is generally between 25-30% in anatomic and cadaver studies [2].