Stomach

Stomach is a sac like dilated portion of the alimentary canal between the oesophagus and the duodenum. It serves as a temporary reservoir of swallowed food and is involved in digestion. The stomach being a hollow muscular organ, its shape varies considerably depending on the quantity of contents in it and the body posture. It can be said to have a J-shape with a long vertical part and a shorter horizontal part.

Anatomy

The stomach is on the left side of the abdominal cavity extending into the epigastrium, the umbilical region, the left hypochondrium and the left lumbar region. The lower part of the stomach can reach upto the second or third lumbar vertebra when it is full. It is continuous with the hollow of the oesophagus above (cranial end) and the duodenum below(caudal end). This portion is called the cardiac end as it lies close to the heart and the caudal end is called the pyloric end or the pylorus meaning the 'gate keeper'.

Curvatures

  • Lesser curvature: It forms the concave right border of the stomach. The upper part of the lower curvature faces towards right while its lower part faces upward and their junction is called the incisura angularis.
  • Greater curvature: It forms the longer, convex left border of the stomach. It extends from the cardio-oesophageal junction to the pylorus and cuts the costal margin at the level of the tenth intercostal cartilage.

Fundus

The upward convexity of the greater curvature forms a semicircular region in the caudal end of the stomach. This part of the stomach that lies above and to the left of the cardio-oesophageal junction is called the fundus. It is the highest part of the stomach reaching the left fifth intercostal space, just below the nipple and lies about 1cm to the right of the midline. On X-rays of individuals taken in upright posture this region will appear dark due to the presence of air.

Body

It forms the major portion of the stomach extending from the lower border of fundus to the level of incisura angularis.

Antrum

It is also called the pyloric antrum and lies to the right of the incisura angularis extending upto the pylorus. It is a relatively dilated part being continuous with the body of the stomach above.

Pylorus

It is also called pyloric canal and is narrower than the antrum being continuous with the first part of the duodenum below. Thus it forms the terminal portion of the stomach. The pylorus lies about 1cm to the right of the midline.

Relations

Anterior surface
Posterior surface

Blood supply

All the arteries which supply the stomach arise from the coeliac trunk or one of its branches.
They are:
  • The left gastric artery which is a direct branch of coeliac trunk.
  • The right gastric artery which arises from the hepatic artery.
  • Short gastric arteries which are branches of the splenic artery.
  • Epiploic arteries, the left gastroepiploic and the right gastroepiploic which are branches of the splenic artery and the gastroduodenal artery(a branch of hepatic artery) respectively.


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