Anatomy
Summary
When theaorta passes through the aortic hiatus in the diaphragm to enter the abdomen, it becomes the abdominal aorta. This occurs near the vertebral level of T12. As it descends, the abdominal aorta gives off numerous branches which can be categorized as those that supply gastrointestinal (GI) structures and non-GI structures. The GI branches, also known as splanchnic arteries, include the celiac trunk, superior mesenteric artery (SMA), and inferior mesenteric artery (IMA). These three arteries branch from the anterior midline of the aorta and are not paired.
The celiac trunk branches near T12, right after the aorta enters the abdomen. It supplies most of the foregut and nearby foregut-derived organs such as the liver, pancreas and gallbladder. It also supplies the spleen. The SMA branches at the L1 level. It supplies the midgut, from the third part of the duodenum to the proximal two-thirds of the transverse colon. Finally, the IMA branches from the aorta at L3. It supplies the hindgut from the distal third of the transverse colon to the rectum. The non-GI branches are paired and come off laterally and posteriorly. They include the inferior phrenic arteries, suprarenal arteries, renal arteries, gonadal arteries, and lumbar arteries. Lastly, where the aorta bifurcates into the common iliac arteries at the vertebral level of L4, it gives off the unpaired median sacral artery, which supplies the lumbosacral area.
Lesson Outline
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FAQs
From the heart, the aorta ascends, then curves downward to become the descending thoracic aorta as it runs through the thoracic cavity. The aorta then passes through the aortic hiatus, an opening in the diaphragm, at the vertebral level of T12, to become the abdominal aorta.
The GI branches are the celiac trunk, superior mesenteric artery, and inferior mesenteric artery.
These branches are major sources of blood supply to the digestive organs. They supply oxygenated blood to the stomach, spleen, liver, gallbladder, pancreas, as well as the small and large intestines.
The inferior phrenic arteries give off a branch, called the superior suprarenal artery, to each adrenal gland. The middle suprarenal arteries come directly from the aorta to supply the adrenal glands. And there are also the inferior suprarenal arteries, which are branches from the renal arteries.
When the abdominal aorta reaches the vertebral level L4, it bifurcates, or splits, into the left and right common iliac arteries. At this bifurcation, the abdominal aorta gives off the median sacral artery.
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