A J-shaped bag that begins at the cardia, just below the diaphragm, and ends at a thick muscular ring on the right
Stomach — cardia to pylorus.
Anatomy · Organs & viscera
Stomach
J-shaped, in the left upper abdomen
Left upper abdomen · digestive system
The stomach is the expandable J-shaped bag between the oesophagus and the duodenum, lying mainly in the left upper abdomen under the left dome of the diaphragm. Its parts are the cardia, fundus, body and pylorus, and it has a short lesser curvature on the right and a long greater curvature on the left. It is the only part of the gut with three muscle layers, including an oblique layer, and it churns food into chyme with acid and pepsin.
How to spot them
- ▸A J-shaped bag hanging from the oesophagus with the fundus at the top left, under the diaphragm
- ▸A short concave lesser curvature (with the lesser omentum) and a long convex greater curvature (with the greater omentum)
- ▸Internally, longitudinal folds called rugae that flatten when the stomach is full
- ▸Ends at the pylorus, a thick muscular ring at about L1 on the transpyloric plane, to the right of the midline
What to know
The dome of this organ, lying under the left diaphragm and often holding a bubble of swallowed air on an upright film
The fundus of the stomach.
A notch on its lesser curvature that marks the junction of body and pyloric part
The incisura angularis of the stomach.
It is the only part of the gut wall with a third, oblique layer of muscle inside the circular layer
Stomach — oblique, circular and longitudinal layers.
Hangs from its long, convex border a fatty apron called the greater omentum
The greater curvature of the stomach.
Its posterior relations, the 'bed', include the pancreas, splenic artery, left kidney, left adrenal gland and spleen
The stomach bed, behind the lesser sac.
Longitudinal folds on the inner surface flatten out when it is distended, allowing it to hold a litre or more
Rugae of the stomach.
A famous fistula: a French-Canadian fur-trade voyageur accidentally shot in 1822 and studied by an army surgeon at Fort Mackinac
Alexis St. Martin and William Beaumont, who observed digestion in the stomach.
Key ideas
- Parietal cells in the gastric glands secrete hydrochloric acid and intrinsic factor, chief cells secrete pepsinogen, and mucus protects the wall from the acid.
- The stomach mixes food into chyme and releases it in small squirts through the pylorus, controlled by the pyloric sphincter.
Quick-fire facts
- •It lies in the epigastrium and left hypochondrium, with the cardia at about T11 and the pylorus at about L1, on the transpyloric plane.
- •Its parts are the cardia, fundus, body and pylorus (with antrum, canal and sphincter).
- •It can stretch from an empty volume of about 50 mL to hold a litre or more.
- •The lesser omentum attaches to the lesser curvature and the greater omentum to the greater curvature.
- •The stomach is supplied by branches of the coeliac trunk: left and right gastric arteries along the lesser curvature, left and right gastro-epiploic arteries along the greater curvature and short gastric arteries to the fundus.
- •The vagus nerves supply it, and cutting them (vagotomy) was once used to treat ulcers.
- •The lesser sac lies behind it, so a perforated posterior ulcer can bleed into the pancreas or lesser sac.
- •Gastric pH is about 1.5 to 3.5.
- •Helicobacter pylori, identified by Marshall and Warren in 1982, is a common cause of stomach ulcers.
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