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Structure

Stomach

Not medically reviewed · Content last updated · 2 min read ·

This is the date the draft was written, not a medical review date.

The stomach is the dilated, J-shaped part of the digestive tube between the oesophagus and the duodenum. It stores and mixes food and begins chemical digestion.

Terminologia Anatomica (Latin): Gaster; Ventriculus · Open in the 3D atlas

Location

It lies in the epigastric and left hypochondriac regions, under the left dome of the diaphragm, with its position varying with posture, filling and body habitus. The stomach bed includes the pancreas, left kidney and adrenal gland, spleen and transverse mesocolon.

Structure

The parts are the cardia, fundus, body, pyloric antrum and pylorus, with lesser and greater curvatures and an angular notch (incisura angularis). The lesser omentum attaches to the lesser curvature and the greater omentum to the greater. The wall has mucosa with gastric glands and rugae, submucosa, three muscle layers (oblique, circular, longitudinal) and serosa; the pyloric sphincter regulates emptying.

Blood supply

All arterial supply derives from the coeliac trunk: the left gastric artery directly, the right gastric artery from the hepatic artery proper, the right gastro-omental (gastroepiploic) artery from the gastroduodenal artery, and the left gastro-omental and short gastric arteries from the splenic artery. Veins drain to the portal system via the splenic and superior mesenteric veins.

Innervation

Parasympathetic supply comes from the anterior and posterior vagal trunks (increasing motility and acid secretion), with the anterior trunk giving hepatic and gastric branches. Sympathetic fibres from T6 to T9 reach the stomach via the greater splanchnic nerves and coeliac plexus; visceral pain is felt in the epigastrium, and the enteric nervous system coordinates local activity.

Function

The stomach acts as a reservoir, mixes food with acid and pepsin into chyme and releases it in small amounts into the duodenum. It secretes hydrochloric acid, pepsinogen, mucus and intrinsic factor (needed for vitamin B12 absorption), and its hormones, such as gastrin, regulate secretion.

Clinical correlations

Peptic ulcer disease is strongly linked to Helicobacter pylori infection and non-steroidal anti-inflammatory drugs; posterior gastric or duodenal ulcers can erode into the splenic or gastroduodenal arteries and cause haemorrhage. Gastric adenocarcinoma, gastritis and outlet obstruction are other major conditions, and vagotomy was historically used to reduce acid secretion.

Common exam points

  • Parts: cardia, fundus, body, pyloric antrum, pylorus; lesser and greater curvatures; incisura angularis.
  • Arterial supply is entirely from the coeliac trunk (left gastric, splenic, common hepatic branches).
  • Left gastric along the lesser curvature, right gastric from the hepatic artery proper; gastro-omental arteries along the greater curvature.
  • Vagal trunks (parasympathetic) increase secretion and motility; sympathetic fibres (T6 to T9) via the coeliac plexus.
  • Posterior wall ulcers may erode the splenic artery; intrinsic factor from parietal cells is needed for vitamin B12.

References

  1. Drake RL, Vogl AW, Mitchell AWM. Gray's Anatomy for Students. Elsevier — Tier 3 (textbook)
  2. Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy. Wolters Kluwer, 8th edition (2018) — Tier 3 (textbook)
  3. Sleisenger and Fordtran's Gastrointestinal and Liver Disease. Elsevier, 11th edition (2020) — Tier 3 (textbook)

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