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Anterior and Posterior Surfaces of the Stomach
Overview
The stomach is a J-shaped, distensible viscus lying in the epigastrium, just inferior to the diaphragm. It has two surfaces - anterior and posterior - and two curvatures (lesser and greater). Its position is fixed only at two points: proximally at the esophagogastric junction and distally at the gastroduodenal junction, giving it considerable mobility.
Developmental Basis for the Two Surfaces
The orientation of the anterior and posterior surfaces arises from embryonic rotation. Around the 4th week of gestation, the primitive stomach rotates 90° clockwise around its longitudinal axis. This causes:
- The left side (which grows faster) to face anteriorly - forming the greater curvature
- The right side to face posteriorly - forming the lesser curvature
This rotation also explains vagal distribution: the left vagus nerve comes to lie on the anterior surface, and the right vagus nerve on the posterior surface - Sleisenger and Fordtran's Gastrointestinal and Liver Disease, p. 830.
Anterior Surface
Relations:
| Structure | Region of Stomach |
|---|
| Left hemidiaphragm | Upper (fundus) |
| Left lobe of liver | Right upper portion |
| Anterior segment of right lobe of liver | Right side |
| Anterior parietal wall of abdomen | Lower left portion (visible below left costal margin when distended) |
The anterior surface of the stomach is adjacent to the anterior abdominal wall, which is why percutaneous endoscopic gastrostomy (PEG) tubes can be placed directly through the abdominal wall into the gastric lumen. - Yamada's Textbook of Gastroenterology, p. 138.
The anterior wall of the stomach - including the cardia, fundus, body, and pyloric part - is visible on inspection when the liver is lifted and the lesser omentum exposed. Depending on the degree of distension, part of the anterior surface may be visible below the left costal margin. - Color Atlas of Human Anatomy Vol. 2, p. 309.
The anterior vagal trunk (from the left vagus) runs on the anterior surface, giving branches to the anterior wall of the fundus, body, and antrum. Gastric branches are numerous and fan-like.
Posterior Surface
Relations:
| Structure | Notes |
|---|
| Left hemidiaphragm | Superior-posterior |
| Left kidney and left adrenal gland | Posterior-lateral |
| Neck, body, and tail of pancreas | Directly posterior - forms the "stomach bed" |
| Aorta and celiac trunk | Medial-posterior |
| Periaortic nerve plexuses | Medial |
| Transverse colon and mesocolon | Inferior border / greater curvature |
| Spleen (concavity) | Left lateral portion |
The posterior wall of the stomach actually forms the anterior wall of the omental bursa (lesser sac). This is a key anatomical relationship - the lesser sac intervenes between the posterior stomach and the structures behind it. - Sleisenger and Fordtran's, p. 830.
The posterior vagal trunk (from the right vagus) runs on the posterior surface. It gives posterior gastric branches to the fundus, body, and antrum, but also gives off the important celiac branch, which passes to the celiac plexus. Compared with the anterior nerve, the posterior nerve terminates more proximally and has fewer gastric branches. - Fischer's Mastery of Surgery, p. (posterior vagal trunk section).
Peritoneal Coverage
The stomach is completely invested by peritoneum, except for a small bare area at the esophagogastric junction. The peritoneum forms double layers:
- Lesser omentum - from the lesser curvature to the liver (hepatogastric and hepatoduodenal ligaments)
- Greater omentum - from the fundus and greater curvature, extending to:
- Transverse colon (gastrocolic ligament)
- Spleen (gastrosplenic ligament)
- Diaphragm (gastrophrenic ligament)
Clinical Relevance
| Point | Significance |
|---|
| Anterior surface abuts abdominal wall | Enables PEG tube placement |
| Posterior surface related to pancreas | Posterior gastric ulcers can erode into the pancreas or bleed from the gastroduodenal artery |
| Posterior surface = anterior wall of lesser sac | Pancreatitis causes pseudocyst formation in the lesser sac, abutting the stomach posteriorly |
| Left vagus on anterior, right vagus on posterior | Explains surgical approach in highly selective vagotomy (anterior seromyotomy) |
| Short gastric vessels between stomach and spleen | Risk of injury during splenectomy; also preserve fundus blood supply |
Sources: Mulholland and Greenfield's Surgery 7e, p. 2220-2221 | Sleisenger and Fordtran's GI and Liver Disease, p. 830 | Yamada's Textbook of Gastroenterology 7e, p. 138 | Color Atlas of Human Anatomy Vol. 2, Internal Organs, p. 309-310