Parts of the Stomach

The stomach is the most dilated part of the GI tract, shaped like a "J," lying in the epigastric, umbilical, and left hypochondriac regions of the abdomen. It is divided into four main regions, plus several named curvatures/landmarks:

1. Cardia

Surrounds the opening where the esophagus enters the stomach (the gastroesophageal junction). It lies just distal to this junction.

2. Fundus

The dome-shaped portion above the level of the cardial orifice - the highest point of the stomach, tucked under the left side of the diaphragm.

3. Body (Corpus)

The largest region of the stomach, between the fundus and the pyloric part. Most of the acid- and pepsinogen-secreting glands (oxyntic mucosa) are here.

4. Pyloric part

The distal end of the stomach, itself subdivided into:

Pyloric antrum - the wider proximal segment
Pyloric canal - narrows toward the pylorus
Pylorus - the terminal segment marked by the pyloric constriction, containing the thickened pyloric sphincter (circular muscle) that guards the pyloric orifice opening into the duodenum. This sits roughly at the transpyloric plane (lower border of L1 vertebra), just right of midline.

Other key landmarks

Greater curvature - the longer, convex left/inferior border; attachment site for the gastrosplenic ligament and greater omentum.
Lesser curvature - the shorter, concave right/superior border; attachment site for the lesser omentum.
Cardiac notch (incisura cardiaca) - the sharp superior angle formed where the esophagus joins the fundus.
Angular incisure (incisura angularis) - a bend along the lesser curvature marking the junction of the body and pyloric part.

Functional grouping

Physiologically the stomach is often grouped into two zones:

Oxyntic (acid-secreting) region: cardia, fundus, and body - contains parietal and chief cells producing acid and pepsinogen.
Pyloric region: antrum and pylorus - contains G cells (gastrin) and mucus-secreting cells, and controls gastric emptying via the pyloric sphincter.

Diagram of stomach anatomy showing fundus, cardia, body, and pyloric antrum

Fig: Stomach regions - fundus, cardia, body, pyloric antrum/canal, and pylorus - along with the greater and lesser curvatures.

Sources:

Gray's Anatomy for Students, p. 370
Grainger & Allison's Diagnostic Radiology, "Anatomy" section
Yamada's Textbook of Gastroenterology, 7th ed. (gastric acid secretion - oxyntic vs. pyloric regions)

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