Learning Objectives

Identify the four anatomical divisions and key surface landmarks of the stomach. Distinguish between the physiological vs. anatomical sphincters at the gastric orifices. Master the arterial supply and venous drainage (Portal system) of the curvatures. Understand the peritoneal attachments (Greater and Lesser Omenta) and their immune functions. Differentiate between Sliding and Rolling hiatus hernias.

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Anatomical Structure & Divisions

The stomach is a “J-shaped” intraperitoneal organ located in the epigastric and umbilical regions. It acts as a reservoir for mechanical and chemical digestion.

• Cardia: Surrounds the superior opening (T11 level).
• Fundus: The gas-filled superior portion (left of the cardia).
• Body: The large central region.
• Pylorus: Connects to the duodenum; consists of the antrum, canal, and the Pyloric Sphincter (L1 level).

 

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Curvatures & Landmarks

• Lesser Curvature: Shorter, concave medial border. Attachment for the hepatogastric ligament (part of the lesser omentum). Features the angular notch.
• Greater Curvature: Long, convex lateral border. Attachment for the greater omentum.

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Sphincters: Control of Flow

Sphincter	Type	Level	Function
Inferior Oesophageal	Physiological	T11	Prevents acid reflux into the oesophagus
Pyloric	Anatomical (Smooth Muscle)	L1	Controls gastric emptying of chyme

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Peritoneal Attachments (Omenta)

The omenta are double-layered peritoneal folds that support the stomach and provide immune defense.

• Greater Omentum: The “Abdominal Policeman.” It hangs from the greater curvature and can adhere to inflamed areas to localize infection.
• Lesser Omentum: Connects the lesser curvature to the liver. It contains the epiploic foramen, the gateway to the lesser sac (omental bursa).

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Neurovasculature

Arterial Supply (All from Coeliac Trunk)

• Lesser Curvature: Left gastric a. & Right gastric a.
• Greater Curvature: Left and Right gastro-omental (gastroepiploic) aa.
• Fundus: Short gastric arteries (from splenic a.).

Innervation

• Parasympathetic: Vagus nerve (Vagal trunks) — stimulates motility and acid secretion.
• Sympathetic: T6-T9 segments via the Greater Splanchnic nerve — inhibits motility.

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Clinical Relevance: Hiatus Hernia

Protrusion of the stomach into the mediastinum through the oesophageal hiatus (T10).

• Sliding (Type I): Most common. The gastro-oesophageal junction slides up. Strongly associated with GORD.
• Rolling (Paraoesophageal): The junction stays in place, but the fundus herniates next to it. Risk of strangulation; often requires surgery.

 

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Activity