Parts and surfaces
The stomach has four parts, two curvatures and two surfaces.
- Cardia: the region around the opening of the oesophagus.
- Fundus: the dome above the level of the cardiac orifice, under the left dome of the diaphragm, where swallowed air collects in the erect position.
- Body: the main part, from the fundus to the angular incisure.
- Pyloric part: the pyloric antrum, which narrows into the pyloric canal, ending at the pylorus. The pylorus is a thick ring of circular smooth muscle, the pyloric sphincter, at about L1 just right of the midline.
The lesser curvature is the short concave right border, with the angular incisure marking the junction of body and pyloric part. The lesser omentum attaches along it. The greater curvature is the long convex left border, attached to the greater omentum and the gastrosplenic ligament. The inside of the empty stomach is folded into longitudinal rugae.
Relations
The stomach lies in front of the lesser sac, and the structures behind the sac form the stomach bed.
- Anterior: the left lobe of the liver, the diaphragm and the anterior abdominal wall.
- Posterior (the stomach bed): the lesser sac, pancreas, splenic artery, left kidney and suprarenal gland, spleen, transverse mesocolon and the left dome of the diaphragm.
- Pylorus: continuous with the first part of the duodenum. The prepyloric vein often marks it at operation.
A posterior gastric ulcer can therefore erode into the pancreas or splenic artery.
Blood supply and innervation
Every gastric artery comes from the coeliac trunk, which arises from the aorta at T12 and divides into the left gastric, splenic and common hepatic arteries. The arteries form one arcade along each curvature.
| Artery | Origin | Territory |
|---|---|---|
| Left gastric | Coeliac trunk | Upper lesser curvature; oesophageal branches |
| Right gastric | Hepatic artery (proper or common) | Lower lesser curvature |
| Left gastro-omental (gastro-epiploic) | Splenic | Upper greater curvature |
| Right gastro-omental (gastro-epiploic) | Gastroduodenal | Lower greater curvature |
| Short gastric | Splenic, near the hilum | Fundus, via the gastrosplenic ligament |
The gastroduodenal artery arises from the common hepatic artery and runs down behind the first part of the duodenum, giving the right gastro-omental and the superior pancreaticoduodenal arteries.
The veins run with the arteries. The left and right gastric veins drain directly into the portal vein; the left gastro-omental and short gastric veins join the splenic vein; the right gastro-omental vein joins the superior mesenteric vein. The splenic and superior mesenteric veins unite behind the neck of the pancreas to form the portal vein.
Nerves
Parasympathetic fibres come from the vagal trunks. The anterior trunk gives hepatic branches and the anterior nerve of Latarjet along the lesser curvature; the posterior trunk gives a coeliac branch and the posterior nerve of Latarjet. The terminal branches spread over the antrum as a crow's foot. Vagal activity increases acid secretion and motility. Sympathetic fibres from T6–T9 arrive via the greater splanchnic nerves and coeliac plexus and carry pain, referred to the epigastrium.
Clinical relevance
Knowledge of the arcades and vagal branches underpins ulcer bleeding, gastric resection and older ulcer surgery.
- Bleeding ulcers: a posterior duodenal ulcer erodes the gastroduodenal artery; a lesser curvature gastric ulcer can erode the left gastric artery.
- Gastrectomy: a distal gastrectomy removes the antrum and is reconstructed as Billroth I, Billroth II or Roux-en-Y; a total gastrectomy is reconstructed with a Roux-en-Y oesophagojejunostomy. A D2 lymphadenectomy removes the nodes along the named arteries.
- Vagotomy: a truncal vagotomy denervated the pylorus and needed a drainage procedure. A highly selective vagotomy kept the nerves of Latarjet to the antrum. Acid suppression and Helicobacter eradication have made both rare.
- Dumping syndrome: rapid emptying after pyloric loss; early dumping follows fluid shifts, late dumping is reactive hypoglycaemia.
- Sleeve gastrectomy: removes most of the greater curvature side for weight loss, dividing the short gastric vessels.
On the specimen
This station shows the stomach with the lesser omentum removed so the coeliac trunk and its branches can be followed to each curvature.
- Coeliac trunk: a short, thick stem from the front of the aorta that divides almost immediately into three.
- Left gastric artery: the smallest branch, running up and to the left to the upper lesser curvature.
- Splenic artery: the largest, tortuous branch, running left along the upper border of the pancreas; its short gastric branches pass to the fundus.
- Common hepatic artery: runs right, then gives the gastroduodenal artery, which dives behind the first part of the duodenum.
- Superior pancreaticoduodenal and right gastro-omental arteries: the terminal branches of the gastroduodenal, one to the pancreatic head, the other along the greater curvature inside the omentum.
- Portal vein and its tributaries: the splenic vein runs straight behind the pancreas, below and behind the tortuous splenic artery; it joins the superior mesenteric vein behind the pancreatic neck.
The parts of the stomach, both curvatures, the pyloric sphincter and the first part of the duodenum are labelled on the same specimen.