Abdominal Arterial and Venous Supply: Celiac, Superior Mesenteric, and Inferior Mesenteric Systems

Overview of Gut Vascular Territories

  • Abdominal gut is classically divided into three embryologic regions, each with its own main artery.
    • Fore-gut → supplied by the Celiac Trunk.
    • Mid-gut → supplied by the Superior Mesenteric Artery (SMA).
    • Hind-gut → supplied by the Inferior Mesenteric Artery (IMA).
  • The lecture proceeds artery-by-artery, naming every principal and accessory branch, and finishes with the matching venous drainage.

Celiac Trunk (Fore-gut)

  • Short, unpaired branch of the abdominal aorta; lies just below the aortic hiatus of the diaphragm.
  • Supplies: distal esophagus, stomach, proximal (1st & 2nd) parts of duodenum, liver, gall-bladder, pancreas, spleen.

1. Left Gastric Artery

  • Smallest of the three primary branches; courses superiorly and left to the cardia.
  • Gives:
    • Esophageal branches → ascend to distal esophagus in a recurrent fashion.
    • Branches to lesser curvature → anastomose with right gastric artery.

2. Splenic Artery

  • Large, tortuous “pig-tail” vessel that tracks along the superior border of pancreas toward the splenic hilum.
  • Gives off:
    • Pancreatic branches ("pancreaticae") → supple body & tail of pancreas.
    • Short gastric arteries → multiple small twigs to gastric fundus along upper greater curvature.
    • Left gastro-epiploic (gastro-omental) artery → long artery running rightward along greater curvature between stomach & greater omentum; will anastomose with right gastro-epiploic.

3. Common Hepatic Artery

  • Runs rightward toward hepatoduodenal ligament; ultimate source of arterial flow to liver & gall-bladder.
3a. Hepatic Artery Proper
  • Ascends within hepatoduodenal ligament toward porta hepatis.
  • Bifurcates into:
    • Right hepatic artery → usually gives the cystic artery to gall-bladder.
    • Left hepatic artery → supplies left lobe & quadrate lobe.
3b. Right Gastric Artery
  • Small branch coursing along right half of lesser curvature; anastomoses with left gastric.
3c. Gastroduodenal Artery (GDA)
  • Descends posterior to the first part of duodenum (near pyloric sphincter).
  • Terminates into:
    • Anterior superior pancreaticoduodenal artery.
    • Posterior superior pancreaticoduodenal artery.
    • Clinical: Both vessels run on respective surfaces of pancreatic head & 2nd part of duodenum; anastomose with inferior PD counterparts from SMA.
  • Also releases the Right gastro-epiploic artery → supplies right greater curvature/greater omentum; meets left gastro-epiploic (splenic) creating an arcade.

Superior Mesenteric Artery (Mid-gut)

  • Emerges anteriorly from aorta inferior to the pancreas; initially lies midline/superomedial then courses downward & to the right toward ileocecal junction.
  • First major named branches form an antero-posterior arterial arcade with GDA derivatives.

1. Inferior Pancreaticoduodenal Arteries

  • Anterior & Posterior inferior branches; ascend on respective pancreatic surfaces.
  • Anastomose with the superior PD arteries (from GDA) → important collateral between celiac & SMA territories.

2. Jejunal and Ileal (Intestinal) Arteries

  • Numerous unnamed branches fanning into mesentery.
    • Jejunal side: fewer arterial arcades, long vasa recta.
    • Ileal side: more arcades, short vasa recta.
  • Supply entire small bowel distal to entry of bile duct.

3. Ileocolic Artery

  • Runs almost in a “beeline” toward ileocecal junction.
  • Divides into
    • Ileal branch
    • Colic branch (to cecum)
    • Appendicular artery → enters mesoappendix; critical for appendectomy (must be ligated to avoid hemorrhage).

4. Right Colic Artery

  • Ascends retroperitoneally to supply ascending colon.

5. Middle Colic Artery

  • Traverses within transverse mesocolon to the transverse colon.
  • Posteriorly displayed in dissection (segment of colon removed to visualize course).

Inferior Mesenteric Artery (Hind-gut)

  • Arises from left-posterior aorta; descends to pelvic brim.
  • Dissection image (Netter) removes small bowel to display aorta, IMA, and cut SMA branches.

Marginal Artery (of Drummond)

  • Continuous arterial arcade along colonic margin; created by serial anastomoses of ileocolic, right colic, middle colic (SMA) with left colic (IMA) branches.
  • Provides collateral if one mesenteric region is obstructed.

1. Left Colic Artery

  • Runs retroperitoneally leftward to supply descending colon.

2. Sigmoid Arteries

  • Several inferiorly angled branches that feed the sigmoid colon.

3. Superior Rectal Artery (terminal IMA branch)

  • Continues into pelvis to upper rectum.
  • Complements:
    • Middle rectal arteries → from internal iliac (not dissected in this course).
    • Inferior rectal arteries → from internal pudendal (studied previously).

Venous Drainage & Portal System

  • Veins mirror arteries but differ at the top of the fore-gut region.

1. Superior Mesenteric Vein (SMV)

  • Drains mid-gut; runs with SMA on right border of mesentery.

2. Inferior Mesenteric Vein (IMV)

  • Drains hind-gut; typically empties into the splenic vein.

3. Splenic Vein

  • Travels horizontally across posterior pancreas.
  • Joins SMV in front of the aorta forming the Portal Vein.
  • Thus, no dedicated “celiac vein.”

4. Portal Vein Significance

  • Carries nutrient-rich, oxygen-poor blood to liver for first-pass metabolism before systemic circulation.

Key Functional & Clinical Correlations

  • Anastomoses
    • Gastro-epiploic (greater curvature) and pancreaticoduodenal (around pancreatic head) provide vital celiac–SMA collaterals.
  • Appendicular artery must be located and ligated during appendectomy to prevent hemorrhage.
  • Marginal artery ensures colonic perfusion even if a specific colic artery is sacrificed.
  • Variations & Tortuosity
    • Splenic artery’s coils are normal yet important to recognize on imaging.
    • Hepatic artery proper can vary; cystic artery usually originates from right hepatic but can differ.
  • Bleeding ulcer posterior to first part of duodenum endangers gastroduodenal artery, causing brisk hemorrhage.
  • Differences in jejunum vs. ileum vasculature (arcades/vasa recta) assist surgeons in identifying bowel segments intra-operatively.