Variation in the vertebral levels of the origins of the abdominal aorta branches: a retrospective imaging study.

Our aim was to investigate the variation in the vertebral levels of the origins of the celiac artery, superior and inferior mesenteric arteries, paired renal arteries, and common iliac arteries. We conducted a retrospective imaging study in a large public secondary hospital on a nonrandom sample of 227 participants. We consecutively included adult patients who had undergone computed tomography angiography of the abdomen and excluded patients with a history of any vertebral abnormality or whose images revealed evidence of a vertebral abnormality or a congenital anomaly of any of the branches of the abdominal aorta. The primary outcome was the frequency distribution of the vertebral levels of the landmarks. The secondary outcomes were the intercorrelations of the vertebral levels of the landmarks and their relationships with age, sex, weight, height, and body mass index. The celiac artery originated at T11/T12-L1/L2, followed by the superior mesenteric artery at T12-L2, the paired renal arteries at T12/L1-L2/L3, the inferior mesenteric artery at L2-L4, and the common iliac arteries at L3-L5. The vertebral levels of the landmarks were positively intercorrelated and stronger between proximate pairs. In addition, the vertebral levels of the landmarks were related to age, but not sex, weight, height, or body mass index. The intercorrelations suggest that a considerable proportion of the variation is accounted for by 'trickle-down' variation; variation in the vertebral level of a proximal landmark results in variation in the vertebral level of the immediate distal landmark. The overarching parameter remains unidentified.