Vagal innervation of the stomach

1. Origin

• Left and right vagus nerves → oesophageal plexus between the tracheal bifurcation and the diaphragm
• Plexus → anterior vagal trunk (left vagus) and posterior vagal trunk (right vagus)
• Rotation of the stomach → left vagus becomes anterior, right vagus posterior
• Trunks enter the abdomen through the oesophageal hiatus

2. Course and relations

At the hiatus

• 2 vagal structures → 88%
• 4 vagal structures → 7%; division above the diaphragm
• More than 4 structures → 5%
• Both trunks → right of the midline of the oesophagus in most specimens
• Anterior trunk → embedded in the anterior oesophageal wall
• Posterior trunk → closer to the aorta than to the oesophagus; thicker than the anterior trunk
• Vagal fibres at the gastro-oesophageal junction → in the peritoneal fold left of the oesophagus

Anterior vagal trunk

• Hepatic division:
  • Separates at the level of the abdominal oesophagus
  • Runs in the avascular part of the hepatogastric ligament, often as several parallel branches
  • Pyloric branch → along the right gastric artery to the pylorus and first part of the duodenum
• Anterior gastric division:
  • Runs along the lesser curvature, 0.5–1 cm from it → anterior nerve of Latarjet
  • Gives 2–12 gastric branches (mean 6)
  • Ends near the incisura angularis as the crow's foot, inconstant

Posterior vagal trunk

• Coeliac division:
  • Largest of the 4 divisions; always single
  • Runs in the gastropancreatic fold → coeliac plexus
• Posterior gastric division:
  • Forms the posterior nerve of Latarjet
  • Ends higher on the lesser curvature, with fewer branches than the anterior nerve
  • Never reaches the duodenum
• Criminal nerve of Grassi:
  • Branch of the posterior trunk behind the gastro-oesophageal junction
  • Supplies the fundus and proximal stomach

3. Branches / Parts

1. Hepatic division → liver, gallbladder, bile duct, pylorus
2. Anterior gastric division → anterior stomach wall, antrum, pylorus
3. Coeliac division → coeliac plexus → small bowel, pancreas, right colon
4. Posterior gastric division → posterior stomach wall, antrum

Function

• Gastric branches to body and fundus → acid secretion (parietal cells)
• Nerves of Latarjet → antral pump and pyloric emptying

Sympathetic and intrinsic supply

• Sympathetic → greater splanchnic nerves, coeliac ganglia; fibres follow the arteries
• Gastroduodenal pain → sympathetic afferents (T5–T10)
• Intrinsic → myenteric plexus of Auerbach, submucosal plexus of Meissner

4. Clinical significance

Vagotomy

1. Truncal vagotomy → trunks divided at the hiatus; denervates all abdominal viscera; needs a drainage procedure (pyloroplasty or gastrojejunostomy)
2. Selective vagotomy → hepatic and coeliac divisions preserved; abandoned
3. Highly selective vagotomy (HSV) → only branches to the body and fundus divided; nerves of Latarjet preserved; no drainage needed
4. HSV dissection → proximal to the crow's foot
5. Proximal crow's foot branch → 7 cm from the pyloroduodenal junction
6. Distal 6–8 cm of the oesophagus → skeletonised to divide all fibres
7. Current indications → intractable or complicated peptic ulcer after failed medical therapy; marginal ulcer after Roux-en-Y gastric bypass