Describe stomach under the following headings : 1. Position 2. Gross features 3. Peritoneal and visceral relation 4. Blood supply and lymphatic drainage 5. Clinical anatomy

1. Position

The stomach is located in the upper left quadrant of the abdominal cavity, primarily beneath the diaphragm and anterior to the pancreas. It lies between the esophagus and the duodenum. Its position is not fixed; it changes with posture and the amount of food it contains. Specifically, it occupies the epigastric, left hypochondriac, and a portion of the left lumbar regions. The long axis of the stomach runs obliquely, from the cardiac orifice (near L4) to the pyloric orifice (near L1).

2. Gross Features

The stomach is a J-shaped, muscular, hollow organ. It can be divided into four main parts:

• Cardia: The region surrounding the esophageal opening.
• Fundus: The dome-shaped portion superior to the cardia.
• Body: The main central region of the stomach.
• Pylorus: The funnel-shaped distal portion, leading into the duodenum. It consists of the pyloric antrum and the pyloric canal.

The stomach has two curvatures:

• Greater Curvature: The longer, convex lateral border.
• Lesser Curvature: The shorter, concave medial border.

The stomach also features the greater omentum attached to the greater curvature and the lesser omentum attached to the lesser curvature.

3. Peritoneal and Visceral Relations

The stomach has both intraperitoneal and retroperitoneal relationships.

• Anterior Relations: The lesser omentum (containing the hepatic artery, portal vein, and common bile duct), the stomach bed (liver, gallbladder, duodenum, transverse colon), and the anterior gastric ligament.
• Posterior Relations: The lesser sac (a potential space), the pancreas, the splenic artery, the left kidney, the adrenal gland, and the splenic vein.
• Superior Relation: The diaphragm.
• Inferior Relation: The transverse colon and the greater omentum.

The stomach is largely covered by the visceral peritoneum. The greater omentum drapes over the anterior surface, while the lesser omentum attaches it to the liver.

4. Blood Supply and Lymphatic Drainage

Blood Supply: The stomach receives arterial blood supply primarily from branches of the celiac trunk:

• Left Gastric Artery: Supplies the lesser curvature.
• Right Gastric Artery: Supplies the inferior aspect of the lesser curvature.
• Gastroduodenal Artery: Supplies the pylorus and duodenum.
• Short Gastric Arteries: Supply the greater curvature.

Venous drainage follows the arterial supply, ultimately draining into the portal vein.

Lymphatic Drainage: Lymphatic vessels from the stomach drain into several lymph nodes:

• Left Gastric Nodes: Along the left gastric artery.
• Right Gastric Nodes: Along the right gastric artery.
• Gastroduodenal Nodes: Along the gastroduodenal artery.
• Pancreaticoduodenal Nodes: Near the head of the pancreas.

These nodes ultimately drain into the celiac and superior mesenteric lymph nodes.

5. Clinical Anatomy

Several areas of the stomach are clinically significant due to their susceptibility to pathology:

• Cardia: Common site for adenocarcinoma.
• Pylorus: Prone to peptic ulcer disease, particularly due to the presence of acid-secreting cells.
• Greater Curvature: Often involved in gastric cancers.
• Gastric Mucosa: Susceptible to gastritis and ulcers, often associated with Helicobacter pylori infection.

The lesser curvature is a common site for bleeding varices in patients with portal hypertension. The proximity of the stomach to other vital organs (pancreas, spleen, liver) means that gastric pathologies can often extend to or affect these adjacent structures. Gastric outlet obstruction, often caused by pyloric stenosis or duodenal ulcers, is a significant clinical presentation.