Stomach is important organ of our body and specially in digestive system. Stomach is involved in digestion of food. The Anatomy of stomach is as follows:
Anatomy of stomach
There are two curvatures in stomach:
- Lesser Curvature (concave border)
- Greater Curvature (convex border)
Both curvatures meet at a sharp angle and form an angle called incisura angularis (angulus ventriculi).
Parts of Stomach
- Cardiac – from which esophagus enters the stomach
Topography of stomach
It is situated in epigastrium; its greater portion is left to median plane. When stomach is full of food content, greater curvature is projected on umbilical region. Cardiac orifice is present at 11th thoracic vertebrae level. Pylorus is present on midline when stomach is empty or corresponds to 12th thoracic level/1st lumbar level. When stomach is empty, the space is occupied by transverse colon.
Structure of Stomach
Innermost layer is tunica mucosa. It contains special glands which produces gastric juice.
Second layer is tela submusoca is present outside the tunica mucosa.
Third layer important layer is tunica muscularis. It is made up of unstraited muscle fibers. It contributes in mixing and movement of food.
Tunica muscularis can be distinguished into three layers as follow:
- External longitudinal layer – it is continuation of muscle fibers of esophagus.
- Middle circular layer
- Inner oblique layer – present in bundles, loops over cardiac orifice, its contraction pushes greater curvature towards cardiac orifice.
Outermost layer is Tunica serosa – it is part of peritoneum.
Peritoneum is absent on the posterior surface, left to the cardiac orifice. It is the place where stomach is in direct contact with diaphragm.
Gastric sac – most distally located part, food falls into this area.
Physiological sphincter (sphincter antri) – separates stomach from pyloric antrum.