Stomach: Miscellaneous | Medical Science Optional Notes for UPSC PDF Download

Stomach-Gross Anatomy

Location

• The stomach, a muscular sac, constitutes the broadest and most expansible segment of the digestive tract.
• Positioned above, it connects to the lower extremity of the esophagus, while below, it is linked to the duodenum.
• Functioning as a food reservoir, it plays a vital role in the digestion of carbohydrates, proteins, and fats.

• Positioned diagonally, the stomach is situated in the upper left portion of the abdomen, spanning the epigastric, umbilical, and left hypochondriac regions.
• Predominantly, it is sheltered beneath the left costal margin and the ribs.

External Characteristics

The stomach exhibits two orifices, two curvatures, and two surfaces.

Two Orifices: 

• The cardiac orifice connects with the lower end of the esophagus, situated behind the left 7th costal cartilage, approximately 2.5 cm from its junction with the sternum, aligning with vertebra T1. 
• The pyloric orifice opens into the duodenum. In the supine position with an empty stomach, it is positioned 1.2 cm to the right of the median plane, at the level of the lower border of vertebra L1 or the transpyloric plane.

Two Curvatures: 

• The lesser curvature is concave, shaping the right border of the stomach and serving as the attachment site for the lesser omentum. 
• The greater curvature is convex, forming the left border of the stomach and providing attachment points for the greater omentum, gastrosplenic ligament, and gastrophrenic ligament.

Two Surfaces: 

• The anterior or anterosuperior surface faces forward and upward. 
• The posterior or posteroinferior surface faces backward and downward.

Divisions

• The stomach is partitioned into two segments:
  1. Cardiac and
  2. Pyloric.
• The larger cardiac portion is further segmented into the fundus and body, while the smaller pyloric portion is divided into the pyloric antrum and pyloric canal.
• The fundus of the stomach constitutes the upper, convex, dome-shaped section located above a horizontal line drawn at the level of the cardiac orifice.
• The body of the stomach occupies the space between the fundus and the pyloric antrum.
• The pyloric antrum and pyloric canal are demarcated by an irregular sulcus, the sulcus intermedius, typically found on the greater curvature. Its length is approximately 7.5 cm.

Stomach-Blood supply

• Arising from the celiac trunk, the left gastric artery.
• Emerging from the common hepatic artery, the right gastric artery.
• Originating from the gastroduodenal artery, the right gastroepiploic artery.
• Stemming from the splenic artery, the left gastroepiploic artery.
• Between 5 to 7 short gastric arteries, also branching from the splenic artery.

The stomach's veins empty into the portal vein, superior mesenteric vein, and splenic vein.

Stomach-Lymphatic drainage

The stomach can be segmented into four lymphatic territories, as depicted in the image. The drainage for these regions is outlined as follows:

• Area a, known as the pancreaticosplenic area, discharges into the pancreaticosplenic nodes positioned along the splenic artery, situated at the posterior aspect of the stomach.
• Area b empties into the left gastric nodes situated along the artery bearing the same name.
• Area c drains into the right gastroepiploic nodes located along the artery of the same designation.

• Lymphatic drainage from area d follows various paths, streaming into the pyloric, hepatic, and left gastric nodes before converging and passing through all these nodes to reach the coeliac nodes.

[Question: 941868]

Stomach - Repeats

• Describe the blood supply and lymphatic drainage of stomach. Add a note on the applied anatomy of both. (2010) 
• Describe stomach under the following headings (2015)
  i. Location
  ii. External features
  iii. Arterial supply
  iv. Clinical anatomy