Abdominal aorta

General characteristics and classification of branches

Descending within the abdominal cavity, the aorta forms a bifurcation (bifurcatio aortae) at the level of the fourth lumbar vertebra (L4). At this point, it divides into two large right and left common iliac arteries (aa. iliacae communes). A slender continuation of the main trunk running downward along the anterior surface of the sacrum to the coccyx is the unpaired median sacral artery (a. sacralis mediana).

All vessels branching from the abdominal aorta are conventionally divided into four groups:

• Unpaired visceral branches (to the gastrointestinal tract and spleen);
• Paired visceral branches (to the kidneys, adrenal glands, and gonads);
• Paired parietal branches (to the abdominal and back walls);
• Unpaired parietal branches (median sacral artery).

Unpaired visceral branches

This group supplies blood to the entire digestive tract within the abdominal cavity, as well as the liver, pancreas, and spleen.

1. Celiac trunk (truncus coeliacus). The highest major vessel, which almost immediately divides into three branches:
2. Left gastric artery (a. gastrica sinistra) — runs to the lesser curvature of the stomach, giving off esophageal branches.
3. Common hepatic artery (a. hepatica communis) — runs to the right toward the hepatoduodenal ligament. It divides into the gastroduodenal (a. gastroduodenalis) and proper hepatic (a. hepatica propria) arteries. The latter runs within the portal triad, dividing into right (which gives off the cystic artery) and left branches.
4. Splenic artery (a. splenica) — the largest and most tortuous branch of the trunk. It runs along the superior margin of the pancreas, supplying it with branches, as well as giving off the short gastric and left gastro-omental arteries.

1. Superior mesenteric artery (a. mesenterica superior). Supplies the small intestine and the right half of the large intestine. It gives rise to:
2. Inferior pancreaticoduodenal artery;
3. Jejunal and ileal arteries (aa. jejunales et ileales) — form a complex system of anastomosing arches (arcades) within the mesentery;
4. Ileocolic artery (a. ileocolica), right and middle colic arteries (a. colica dextra et media) — supply the ileocecal junction, appendix, ascending colon, and part of the transverse colon.

1. Inferior mesenteric artery (a. mesenterica inferior). Participates in the blood supply to the left divisions of the large intestine, forming anastomoses with the middle colic artery.

Paired visceral branches

These vessels branch symmetrically on both sides of the aorta and supply the organs of the retroperitoneal space and pelvis:

• Middle suprarenal arteries (aa. suprarenales mediae) — arise between the celiac trunk and the superior mesenteric artery, running toward the hilum of the adrenal glands.
• Renal arteries (aa. renales) — large trunks originating at the L1–L2 level. The right renal artery is longer than the left and passes posterior to the inferior vena cava. Both arteries frequently give off inferior suprarenal arteries and ureteric branches.
• Gonadic arteries — testicular (aa. testiculares) in males and ovarian (aa. ovaricae) in females. They descend along the psoas major muscle. The testicular artery enters the inguinal canal, whereas the ovarian artery descends into the lesser pelvis within the suspensory ligament of the ovary.

Parietal branches

Provide blood flow to the muscles, fasciae, and skin of the abdominal wall:

• Inferior phrenic arteries (aa. phrenicae inferiores) — arise immediately below the aortic hiatus of the diaphragm. They give off superior suprarenal arteries.
• Lumbar arteries (aa. lumbales I–IV) — four pairs of vessels passing posterior to the psoas major muscle. They give off dorsal branches to the back muscles, spinal branches into the vertebral canal, and anterior branches supplying the abdominal wall.
• Median sacral artery (a. sacralis mediana) — a slender unpaired trunk to the sacrum and coccyx.

Major interarterial anastomoses

An extensive network of collaterals exists within the abdominal cavity, which is of paramount importance in surgery:

• Gastric arcades: the left and right gastric arteries anastomose along the lesser curvature; the left and right gastro-omental arteries anastomose along the greater curvature.
• Pancreaticoduodenal zone: the superior pancreaticoduodenal arteries (from the celiac trunk system) connect with the inferior ones (from the superior mesenteric), ensuring a robust connection between the two major vascular beds.
• Marginal artery (Drummond's arcade): formed along the colon. A key site is the junction of the left branch of the middle colic artery (superior mesenteric basin) with the left colic artery (inferior mesenteric basin).
• Intestinal arcades: jejunal and ileal branches form multiple tiers of arches. Near the jejunum, there are fewer arches and longer straight vessels (vasa recta); near the ileum, there are numerous arcade tiers and short straight vessels.

Class and exam questions

What else to study on this topic

• Detailed topography of the celiac trunk branches
• Structure of the portal triad
• Architectonics of small intestine arcades
• Clinical anatomy of Drummond's marginal artery
• Surgical anatomy of the right hemicolon

Other topics in the "Angiology" section

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