13. Anatomy of Abdominal Visceral Vessels

I. Abdominal Visceral Arteries

• Major unpaired visceral arteries arise from abdominal aorta
• Celiac trunk → Foregut; SMA → Midgut; IMA → Hindgut

1. Celiac Trunk

• Celiac trunk: T12 level → Supplies foregut organs
• Left gastric artery: Lesser curvature of stomach + lower esophagus
• Splenic artery: Spleen, pancreatic body/tail, stomach

• Branches: Short gastric arteries, left gastroepiploic artery, pancreatic branches

• Common hepatic artery: Main arterial route to liver/gallbladder/duodenum/pancreas

• Proper hepatic artery → Right and left hepatic arteries
• Right hepatic artery → Cystic artery
• Right gastric artery → Lesser curvature
• Gastroduodenal artery → Right gastroepiploic artery + superior pancreaticoduodenal arteries

2. Superior Mesenteric Artery

• SMA: L1 level → Supplies midgut
• Territory: Distal duodenum, jejunum, ileum, cecum/appendix, ascending colon, proximal 2/3 transverse colon
• Branches: Inferior pancreaticoduodenal, jejunal, ileal, ileocolic, right colic, middle colic arteries

3. Inferior Mesenteric Artery

• IMA: L3 level → Supplies hindgut
• Territory: Distal 1/3 transverse colon, descending colon, sigmoid colon, upper rectum
• Branches: Left colic, sigmoid arteries, superior rectal artery

II. Abdominal Visceral Veins

Portal Venous System

• Portal vein: Formed by SMV + splenic vein → Enters liver at porta hepatis
• SMV: Small intestine, ascending colon, proximal 2/3 transverse colon, pancreatic head
• IMV: Distal 1/3 transverse colon, descending colon, sigmoid colon, superior rectum
• IMV usually joins splenic vein
• Splenic vein: Spleen, pancreatic body/tail, short gastric veins, left gastroepiploic vein
• Gastric veins: Left and right gastric veins usually drain to portal vein
• Right gastroepiploic vein usually drains to SMV

Systemic Venous System

• Middle and inferior rectal veins → Internal iliac veins → Common iliac veins → IVC
• Esophageal veins → Azygos system → SVC

III. Collateral Circulation

• Pancreaticoduodenal arcades: Celiac trunk ↔ SMA
• Marginal artery of Drummond: Continuous arterial arcade along colon margin → SMA ↔ IMA
• Arc of Riolan: Inconstant collateral between middle colic artery (SMA) and left colic artery (IMA)

Portosystemic Anastomoses

• Lower esophagus: Left gastric vein ↔ esophageal veins/azygos → Esophageal varices
• Rectum: Superior rectal vein ↔ middle/inferior rectal veins → Rectal varices
• Umbilicus: Paraumbilical veins ↔ abdominal wall veins → Caput medusae
• Retroperitoneum: Colic/pancreaticoduodenal veins ↔ retroperitoneal/lumbar veins

IV. Lymphatic Drainage and Surgical Relevance

• Lymphatic drainage follows arterial supply
• Foregut → Celiac nodes
• Midgut → Superior mesenteric nodes
• Hindgut → Inferior mesenteric nodes
• Nodes → Intestinal lymph trunks → Cisterna chyli → Thoracic duct
• Surgical relevance: Vessels define safe ligation planes and oncological lymphadenectomy fields