Stomach Anatomy
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Direct answer
J-shaped and the most distensible part of the gut, the stomach occupies the left upper abdomen from the cardia (behind the seventh left costal cartilage, T10–T11) to the pylorus (L1, right of the midline), with a fundus doming under the left cupola of the diaphragm and a body and pyloric antrum between the lesser and greater curvatures. Its capacity grows from about 30 millilitres at birth to 1–1.5 litres in the adult. Behind it lies the stomach bed — pancreas, spleen, left kidney and suprarenal, splenic artery, transverse colon with its mesocolon and the left crus of the diaphragm — separated by the lesser sac. All its arteries descend from the coeliac trunk, and vagal trunks ride the curvatures, which is why both surgery (vagotomy, gastrectomy) and disease (ulcer, carcinoma) follow curvature anatomy.
What you must remember
- Parts and orifices: cardia, fundus, body, pyloric antrum and canal; the fundus reaches the fifth left intercostal space, and gas collects there on an erect film — the stomach bubble.
- Stomach bed (posterior relations): pancreas, left kidney, left suprarenal, splenic artery, spleen, transverse colon and mesocolon, left crus of diaphragm — all separated by the lesser peritoneal sac.
- Arterial supply, all from the coeliac trunk: left gastric (direct branch, on the lesser curvature) and right gastric (from the hepatic); right gastroepiploic (from the gastroduodenal) and left gastroepiploic with short gastrics (from the splenic) on the greater curvature.
- Venous drainage: right and left gastric veins to the portal vein; right gastroepiploic to the superior mesenteric, left gastroepiploic and short gastrics to the splenic — the gastric veins enlarge in portal hypertension.
- Nerve supply: anterior (left) vagal trunk supplies the anterior surface and gives the crow's foot of gastric branches to the body; posterior (right) trunk gives a coeliac branch; sympathetic fibres from the coeliac plexus are vasomotor and pain-carrying.
- Lymph drainage: along both curvatures to left and right gastric, gastroepiploic and short gastric nodes, all finally to the coeliac nodes — and via the thoracic duct to the left supraclavicular (Virchow's) node in carcinoma.
- Clinical classic: infantile hypertrophic pyloric stenosis — firstborn boys around three to six weeks, projectile non-bilious vomiting, visible peristalsis left to right, and a palpable olive-shaped mass.
Working through the vagotomy story
The history of ulcer surgery is a tour of gastric nerve anatomy. Truncal vagotomy cut both trunks at the oesophageal hiatus, curing acid hypersecretion but denervating the liver, pancreas and antrum, so a drainage procedure was needed and diarrhoea and dumping followed. Selective vagotomy spared the coeliac and hepatic branches but still denervated the antrum. Highly selective (parietal cell) vagotomy — the examinably elegant one — divided only the crow's foot branches to the body and fundus, sparing the antral branches of the nerve of Latarjet, so antral motility and emptying survived without drainage. The crow's foot is drawn on the body like a bird's claw, with the last "toe" left intact to protect the antrum.
A parallel applied thread is penetrating ulcer disease. A posterior duodenal or gastric ulcer erodes backwards: the gastroduodenal artery behind the first part of the duodenum bleeds heavily, and a posterior gastric ulcer may bore into the pancreas, causing boring back pain and rising serum amylase — the stomach bed relations made clinical.
High-yield viva angles
Three questions recur. "Why does gastric carcinoma present with a left supraclavicular node?" — because lymph from the coeliac nodes reaches the thoracic duct, whose terminal flow deposits tumour in Virchow's node; a hard left supraclavicular node with dyspepsia in an older Indian patient demands an endoscopy. "Which curvature does a gastric ulcer favour?" — the lesser curvature, where the left gastric artery's territory and mucosal vulnerability coincide. And "why is pyloric stenosis vomiting non-bilious?" — the obstruction is proximal to the ampulla of Vater, so bile never reaches the stomach contents. Each answer converts a list of relations into a clinical sign.
Frequently asked questions
Which artery supplies the lesser curvature and what are its origins?
The left gastric artery arises directly from the coeliac trunk; the right gastric arises from the common or proper hepatic artery; the two anastomose along the lesser curvature.
Name the structures forming the stomach bed.
Pancreas, left kidney and suprarenal, spleen, splenic artery, transverse colon with its mesocolon, and the left crus of the diaphragm, separated from the stomach by the lesser sac.
Where does gastric lymph ultimately drain, and which distant node signals carcinoma?
Coeliac nodes around the coeliac trunk; distal spread through the thoracic duct to the left supraclavicular (Virchow's) node is classical.
What is spared in highly selective vagotomy?
The antral branches of the nerve of Latarjet (the last crow's foot twig) and the coeliac branch, preserving antral motility and avoiding a drainage procedure.
Why is the vomitus non-bilious in infantile hypertrophic pyloric stenosis?
The hypertrophied pylorus obstructs outflow proximal to the duodenum and the ampulla of Vater, so no bile mixes with the gastric contents.