Feb 11, 2012

conti.... Stomach




The lesser curvature forms the right border of the stomach and extends from the cardiac orifice to the pylorus . It is suspended from the liver by the lesser omentum.

The greater curvature is much longer than the lesser curvature and extends from the left of the cardiac orifice, over the dome of the fundus, and along the left border of the stomach to the pylorus.

The gastrosplenic omentum (ligament) extends from the upper part of the greater
 curvature to the spleen, 




Relations of the stomach:-
Anteriorly:                                                                  Posteriorly:
1.The anterior abdominal wall.                                    1.The lesser sac.
2.The left costal margin.                                              2.The diaphragm.
3.The left pleura and lung.                                  3.The spleen.
4.The diaphragm.                                                         4.The left suprarenal gland.
5.The left lobe of the liver.                                  5.The upper part of the left kidney.
6.The splenic artery.
7.The pancreas.
8.The transverse mesocolon
9.The transverse colon.
  


Blood Supply
Arteries
The arteries are derived from the branches of the celiac artery.
1-The left gastric artery arises from the celiac artery. It passes upward and to the left to reach the esophagus and then descends along the lesser curvature of the stomach.
It supplies the lower third of the esophagus and the upper right part of the stomach.
2-The right gastric artery arises from the hepatic artery at the upper border of the pylorus and runs to the left along the lesser curvature. It supplies the lower right part of the stomach.
3-The short gastric arteries arise from the splenic artery at the hilum of the spleen and pass forward in the gastrosplenic omentum (ligament) to supply the fundus.

4-The left gastroepiploic artery arises from the splenic artery at the hilum of the spleen and passes forward in the gastrosplenic omentum (ligament) to supply the stomach along the upper part of the greater curvature.
5-The right gastroepiploic artery arises from the gastroduodenal branch of the hepatic artery. It passes to the left and supplies the stomach along the lower part of the greater curvature.

Veins
        The veins drain into the portal circulation .
1-Left gastric vein 
2-Right gastric veins. drain directly into the portal vein.
3-Short gastric veins.
4-Left gastroepiploic veins. join the splenic vein.
5-Right gastroepiploic vein. joins the superior mesenteric vein.



Lymph Drainage
          The lymph vessels follow the arteries into the
1-Left and right gastric nodes.
2-The left and right gastroepiploic nodes.
3-And the short gastric nodes.
          All lymph from the stomach eventually passes to the celiac nodes,which are located
          around the root of the celiac artery on the posterior abdominal wall.
Nerve Supply
The nerve supply includes:
1-Sympathetic fibers derived from the celiac plexus.
2-Parasympathetic fibers from the right and left vagus nerves.

The anterior vagal trunk,which is formed in the thorax from the left vagus nerve, enters the abdomen on the anterior surface of the esophagus.
 The trunk, which may be single or multiple, then divides into branches that supply the anterior surface of the stomach.
A large hepatic branch passes up to the liver, and from this a pyloric branch passes down to the pylorus.

The posterior vagal trunk,which is formed in the thorax from the right vagus nerve, enters the abdomen on the posterior surface of the esophagus.
The trunk then divides into branches that supply mainly the posterior surface of the stomach.

A large branch passes to the celiac and superior mesenteric plexuses and is distributed to the intestine as far as the splenic flexure and to the pancreas.

The sympathetic innervation of the stomach carries a proportion of pain-transmitting nerve fibers.
Whereas the parasympathetic vagal fibers are secretomotor to the gastric glands and motor to the muscular wall of the stomach.

The pyloric sphincter receives motor fibers from the sympathetic system and inhibitory fibers from the vagi.



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