Vascular Anatomy of the Abdominal Aorta and the Inferior Vena Cava

Abdominal Aorta

The abdominal aorta continues from the thoracic aorta as it passes posterior to the median arcuate ligament and between the crura of the diaphragm (aortic hiatus), in front of the body of the T12 vertebra and then descends slightly to the left of midline. Clinically, the abdominal aorta is often divided into suprarenal and infrarenal arterial segments. The rationale for this division is the higher incidence of atherosclerotic and aneurysmal disease in the infrarenal abdominal aorta and the increased complexity of interventions involving the suprarenal portion. It terminates as a bifurcation into two common iliac arteries anterior to the fourth lumbar vertebra.

As the aorta descends through the abdominal cavity, the infrarenal aorta gives off anterior, lateral, and posterior branches. Anterior branches include the celiac trunk, superior mesenteric artery, and inferior mesenteric artery, which supply the gastrointestinal viscera, as well as the phrenic and gonadal arteries ( Fig. 19.1 ).

The bilateral inferior phrenic arteries may arise together as a trunk or as independent vessels just above or at the origin of the celiac trunk. They pass upward from the abdominal aorta to the diaphragm and give off multiple branches to the adrenal glands. The inferior phrenic artery also supplies the Glisson capsule of the liver through anastomoses at the bare area of the liver within the triangular ligaments.

The celiac trunk arises just below the aortic hiatus. A search for its origin at angiography should begin from the left pedicle of the T12 vertebra to the superior endplate of the L1 vertebra. Asymptomatic narrowing or occlusion of the origin of the celiac trunk should be anticipated by thorough review of any preprocedural imaging. It is the major supply to the foregut (liver, gallbladder, pancreas, stomach, lower esophagus) and spleen ( Fig. 19.2 ).