The iliolumbar artery-anatomic considerations and details on the common iliac artery trifurcation.

The iliolumbar artery (ILA) of Haller is the largest nutrient pedicle of the ilium and its detailed knowledge is important for various surgical procedures that approach the lumbosacral junction, the L4/L5 disk space, the sacroiliac joint, the iliac and psoas muscles, or the lumbar spine. Also the ILA is relevant for various techniques of embolization. We aimed to evaluate the anatomic and topographic features of the ILA, by dissection on 30 human adult pelvic halves and on 50 angiograms. ILA was a constant presence and it emerged at Level A (from the common iliac artery (CIA), 8.75%), Level B (from the CIA bifurcation, 2.5%), Level C (from the internal iliac artery (IIA), 52.5%), Level D (from the IIA bifurcation, 3.75%), and Level E (from the posterior trunk of the IIA, 32.5%). Level B of origin of the ILA corresponds to a trifurcated CIA (morphology previously unreported), while Level D corresponds to a trifurcated IIA. A higher origin of the ILA corresponds to a more transversal course of it. A descending lumbar branch that leaves the iliac arterial system independently to enter the psoas major muscle, as seen in 48% of cases, may be misdiagnosed as ILA. Surgical interventions in the lumbar, sacral, and pelvic regions must take into account the variable origins of the ILA from the iliac system that can modify the expected topographical relations and may lead to undesired hemorrhagic accidents.