Abdomen:Hollow viscus:Stomach

The **stomach** lies between the oesophagus and duodenum in the upper abdomen. It lies on the left side of the abdominal cavity caudal to the diaphragm.

The stomach is a muscular bag, and divided into distinct regions:

* cardia: the area that receives the oesophagus (gastro-oesophogeal junction). It lies left of the midline at T10, behind 7th costal cartilage.
* fundus: formed by the upper curvature, above the level of the cardia and is in contact with left dome of the diaphragm (where the stomach bubble sits)
* body (corpus): the main central region of the organ (between fundus to antrum).
* pylorus (antrum): the lower section of the stomach that facilitates emptying into the small intestine, consisting of an antrum that narrows into a pyloric canal. A sphincter guards the distal end of the canal.

There are two smooth muscle sphincters, oesophageal and pyloric, that dictate entry into and exit from the stomach. These are under the control of several mechanisms including stimulant (parasympathetic) and inhibitory (orthosympathetic) control from the anterior gastric, posterior, superior and inferior coeliac and myenteric nerve plexuses.

The inner mucosal surface has many rugal folds that act to increase the surface area of the stomach lining and increase its efficiency.

Relations

* anteriorly - left lobe of liver, anterior abdominal wall, left hemidiaphragm
* posteriorly - lesser sac, stomach bed (left crus, splenic artery, body of pancreas, transverse mesocolon, upper part of left kidney, left suprarenal gland, spleen and left colic flexure).
* right side: aorta, coeliac trunk, coeliac plexus and ganglia, and coeliac lymph nodes.

Blood supply

* arterial supply
	+ lesser curvature: right gastric artery (inferiorly) and left gastric artery(superiorly)
	+ cardia: left gastric artery
	+ greater curvature: right gastroepiploic artery (inferiorly) and left gastroepiploic artery, in the layer of the greater omentum, and short gastric arteries (superiorly)
	+ fundus of the stomach: six short gastric arteries
* venous drainage
	+ left and right gastric veins drain to portal vein
	+ short gastric vein and left gastroepiploic vein drain to splenic vein
	+ right gastroepiploic vein drain to superior mesenteric artery

Lymphatic drainage: ultimately all arteries drain into the *coeliac lymph nodes*

* The lesser curvature lymph passes to left and right gastric nodes alogn the left and right gastric arteries
* The upper greater curvature pass the left gastroepiploic nodes and to the pancreaticosplenic node
* The lower greater curvature, drain into subpyloric node and hepatic nodes which enters the right gastric.

Nerve supply:

* Sympathetic fibres from celiac and splanchnic ganglia and plexus (cause vasomotor, and pyloric sphincter contraction) and accompanied by afferent pain fibres.
* Parasympathetic supply from vagus, control motility and secretion.
	+ The anterior vagal trunk (from the left vagus nerve), lies on the anterior oesophageal wall and it gives off gastric branches to supply fundus, body, antrum and sphincter.
	+ The posterior vagal trunk (from left vagus nerve), lies behind, and gives coeliac branches and gastric branches to the fundus, body, and antrum.