Stomach

The stomach is a J-shaped muscular bag that has the following functions:

  1. Mechanical and chemical digestion of food

  2. Storage of food

Its anatomical relations can be described as:

  1. Inferior to the esophagus and the dome of the diaphragm

  2. Posterior to the left lobe of the liver, gall bladder and the rest of the diaphragm

  3. Anterior to the pancreas, left kidney and left adrenal gland, and the spleen.

The stomach has four distinct parts and these include:

  1. Cardia

    • Near the gastroesophageal junction

  2. Fundus

    • Above the gastroesophgeal junction

  3. Body

    • Between the fundus and antrum

  4. Pylorus

    • The pylorus is the distal part of the stomach and is divided into the pyloric antrum (wide part) and the pyloric canal (narrow part).

    • The pyloric orifice is surrounded by the pyloric sphincter, which is a well defined muscular sphincter that controls movement of food out of the stomach and prevents reflux of the duodenal contents into the stomach.

Internally, the mucosa of the stomach forms longitudinal folds otherwise known as rugae which helps increase the surface area of the stomach.

Other features of the stomach can be catergorized as:

Blood Supply:

  1. The right and left gastric arteries supply the lesser curvature of the stomach

  2. The right and left gastroepiploic arteries supply the greater curvature of the stomach

  3. The short gastric arteries supply the fundus of the stomach.

Venous Drainage:

The right and left gastric veins, left gastroepiploic vein, short gastric veins and right gastroepiploic vein drain the respective parts of the stomach.

Innervation:

The innervation of the stomach is by the enteric nervous system, which consists of the myenteric plexus of Auerbach. The enteric nervous system is modulated by the parasympathetic and sympathetic nervous systems.

  1. Parasympathetic innervation is provided by the vagus nerve.

  2. Sympathetic innervation is provided by the greater splanchnic nerve.

 

Clinical Notes:

A perforation of the stomach can damage the surrounding structures due to the acidic nature of the contents of the stomach. Additionally, erosion of the splenic artery can lead to severe hemorrhage.