Anatomy of the Stomach

The stomach has many different compartments and is composed of many sections. It is derived from the foregut, located in the left hypochondrium, epigastrium, and umbilical regions. Its separated into the fundus, body, and pyloric regions. The pyloric region is split into three different areas: the pyloric antrum, canal, and sphincter. Finally, the stomach is located from T10-L1 vertebral columns.

The fundus usually contains gas and is located at the superior portion of the stomach. The body of the stomach lies between the fundus and angular notch of the stomach. The pyloric area is located at the level of the first lumbar vertebrae, and extends from the angular notch of the stomach to the gastro-duodenal junction.

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The pyloric region is the thickest part of the stomach, and its pyloric sphincter directs what gets into the doedenum and what doesn't. Two thirds of the time the pyloris remains in an open or relaxed state, allowing small quantities of food to pass into the duodenum. Because it is so narrow, it only allows food that is well emulsified to pass through into the first part of the small intestine.

The organ itself is completely covered in peritoneum, which then passes to the liver as the lesser omentum and also hangs down from the stomach, fuses with the transverse colon as the greater omentum. The upper and lower borders of the stomach are called the lesser and greater curvature, respectifully.

In order to preven gastric reflux, the cardio-oesophageal junction is the most fixed point. It is at this location that the right crux of the diaphragm, mucosal rosette, lower oesophageal sphincter and intra-abdominal part of the oesophagus contract and prevent contents of the stomach back up the oesophagus.

The stomach lies just under the left side of the diaphragm. At its posterior side there are a few structures that are important clinically. Its posterior wall is covered by peritoneum of the anterior wall of the omentum bursa (lesser sac), and the bed is covered by the posterior wall of the lesser sac.The bed consists of the dome of the diaphragm, left crus, the top part of the left kidney which is overlaid by a few structures, namely: the tail of the pancreas, the spleen and the suprarenal gland.

On the lower border of the stomach you will see part of the pancreas showing through, with the transverse mesocolon passing on the underside of the inferior border of the pancreas. While to the right of the lesser curvature, you will see the aorta, with the coeliac trunk diving into it's three branches, and coeliac ganglia on either side with coeliac lymph nodes.

The blood supply of the stomach comes from the embryological foregut, so it is supplied by the artery of the foregut: the coeliac trunk. Along the lesser curvature the left and right gastric arteries anastomose between the layers of the lesser omentum. The right gastric artery is a branch of the gastroduodenal or hepatic artery. The fundus and upper part of the greature curvature receive its blood supply from the short gastric arteries, which pass from the splenic artery in the gastrosplenic ligament. Lastly, the rest of the stomach is supplied by the right and left gastroomental arteries from the gastroduodenal artery and the splenic artery respectively. Branches of these arteries pass down the omentum, and are the largest arteries supplying the peritoneum. These arteries make sure that the mobile omentum receives all the phagocytes it needs to combat infection. Veins of the same names drain into the hepatic portal vein itself or its splenic or mesenteric tributaries.

Ultimately, all lymph drainage reaches the coeliac nodes. The greatest area of drainage in the stomach is along the left gastric artery and are called the superior gastric nodes. The second largest drainage area is found by the right gastroomental artery and are called the inferior gastric nodes. The most common gastric cancers are found in the nodes located along the pyloric region.

Nerve supply to the stomach are primarily through the vagal nerve with controls motility and secretion. The anterior and posterior vagal trunks, from the oesophageal plexus form the anterior and posterior nerves of Latarjet. These two nerves run down the lesser omentum, giving off branches to the anterior and posterior of the stomach.

Anatomy of the Stomach

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