Abdominal Vasculature

Abdominal Aorta - Main Highway

• Origin: Aortic hiatus (diaphragm), T12.
• Termination: Bifurcates to common iliacs, L4.
• Relations: Posterior to pancreas & L renal vein; Anterior to vertebral bodies; IVC on right.
• Branches:
  • Unpaired Visceral (Anterior): 📌 Celiac (T12), SMA (L1), IMA (L3).
  • Paired Visceral (Lateral): Middle Suprarenal, Renal (L1-L2), Gonadal (L2).
  • Paired Parietal (Posterolateral): Inferior Phrenic, Lumbar (4 pairs, L1-L4).
  • Terminal: Bifurcates to Common Iliacs (L4); Median Sacral (posterior).

⭐ Origin: Aortic hiatus (diaphragm, T12). Termination: Bifurcates to common iliacs (L4).

Celiac Trunk - Upper Gut Supply

• Origin: Anterior aorta, T12/L1. Supplies foregut.
• Branches (📌 Mnemonic: "Left Hand Side" - LHS):
  • Left Gastric Artery: Stomach (lesser curve), lower esophagus.
  • Splenic Artery: Spleen, pancreas, stomach (fundus, greater curve).
    • Sub-branches: Short gastric, left gastro-omental arteries.
  • Common Hepatic Artery:
    • Proper Hepatic Artery: Liver, gallbladder (cystic a.), stomach (right gastric a.).
    • Gastroduodenal Artery (GDA): Duodenum, pancreas head, stomach (right gastro-omental a.).

⭐ The gastroduodenal artery (from common hepatic) erosion by posterior duodenal ulcer causes severe hemorrhage.

Mesenteric Arteries - Gut's Long Haul

• Superior Mesenteric Artery (SMA): Origin L1, supplies midgut.
• Inferior Mesenteric Artery (IMA): Origin L3, supplies hindgut.

⭐ Griffith's point (splenic flexure) is a watershed area between SMA & IMA supply, vulnerable to ischemia.

Venous Drainage - Rivers Returning

• Inferior Vena Cava (IVC):
  • Forms at L5 (common iliac veins); ends in right atrium.
  • Tributaries: Lumbar, R. Gonadal, R. Suprarenal, Renal, Hepatic.
• Portal Vein:
  • Forms: SMV + Splenic Vein (post. to pancreas neck).
  • Drains: GIT, spleen, pancreas, gallbladder.
  • Tributaries: SMV, Splenic, Gastric (L&R), Cystic, Paraumbilical.

• Portocaval Anastomoses: Portal-systemic links; key in portal hypertension (→ varices).
  • 📌 GURES Sites: Gut (esophageal), Umbilicus, Rectal, Retroperitoneal, Spleen/Suprarenal & intrahepatic.

⭐ L. gonadal & L. suprarenal veins → L. renal vein; R. counterparts → IVC directly.

Clinical Correlations - Vascular Hotspots

• Abdominal Aortic Aneurysm (AAA)
  • Def: Aortic dilation >3 cm.
  • Risks: Atherosclerosis, smoking, HTN, male >65y, family Hx.
  • Location: Infrarenal (surgery >5.5 cm).
• Mesenteric Ischemia
  • Acute (embolus), Chronic (atherosclerosis).
  • Vulnerable: Watershed zones (Griffith's, Sudeck's).
• Portal Hypertension (Portal pressure >5-10 mmHg)
  • Causes: Pre- (PVT), Intra- (cirrhosis), Post-hepatic (Budd-Chiari).
  • Consequences: Varices (esoph, gastric, rectal), ascites, splenomegaly, caput medusae.
• Compression Syndromes
  • Nutcracker: L. renal vein compressed (SMA & aorta).
  • SMA Syndrome: Duodenum (D3) compressed (SMA & aorta).

⭐ Most common AAA site: infrarenal (↓ vasa vasorum, ↓ elastin).

High‑Yield Points - ⚡ Biggest Takeaways

• Celiac trunk supplies foregut; branches: Left Gastric, Splenic, Common Hepatic arteries.
• Superior Mesenteric Artery (SMA) supplies midgut derivatives; watch for SMA syndrome.
• Inferior Mesenteric Artery (IMA) supplies hindgut derivatives; Marginal Artery of Drummond is key anastomosis.
• Portal vein is formed by Splenic vein and SMV; crucial in portal hypertension.
• Key portocaval anastomoses: esophageal varices, caput medusae, internal hemorrhoids.
• Left renal vein passes between SMA and aorta (Nutcracker syndrome); gonadal arteries arise from aorta.