The lesser omentum (small omentum or gastrohepatic omentum) is the double layer of

peritoneum The peritoneum is the serous membrane forming the lining of the abdominal cavity or coelom in amniotes and some invertebrates, such as annelids. It covers most of the intra-abdominal (or coelomic) organs, and is composed of a layer of mes ...

that extends from the

liver The liver is a major organ only found in vertebrates which performs many essential biological functions such as detoxification of the organism, and the synthesis of proteins and biochemicals necessary for digestion and growth. In humans, it i ...

to the lesser curvature of the stomach, and to the first part of the

duodenum The duodenum is the first section of the small intestine in most higher vertebrates, including mammals, reptiles, and birds. In fish, the divisions of the small intestine are not as clear, and the terms anterior intestine or proximal intestine m ...

. The lesser omentum is usually divided into these two connecting parts: the hepatogastric ligament, and the

hepatoduodenal ligament The hepatoduodenal ligament is the portion of the lesser omentum extending between the porta hepatis of the liver and the superior part of the duodenum. Running inside it are the following structures collectively known as the portal triad: * he ...

Structure

The lesser omentum is extremely thin, and is continuous with the two layers of

which cover respectively the antero-superior and postero-inferior surfaces of the stomach and first part of the duodenum. When these two layers reach the lesser curvature of the stomach and the upper border of the duodenum, they join and ascend as a double fold to the porta hepatis. To the left of the porta, the fold is attached to the bottom of the fossa for the ductus venosus, along which it is carried to the diaphragm, where the two layers separate to embrace the end of the esophagus. At the right border of the lesser omentum, the two layers are continuous, and form a free margin which constitutes the anterior boundary of the

omental foramen In human anatomy, the omental foramen (epiploic foramen, foramen of Winslow after the anatomist Jacob B. Winslow, or uncommonly aditus; la, Foramen epiploicum), is the passage of communication, or foramen, between the greater sac (general cavity ...

Divisions

Anatomically, the lesser omentum is divided into ligaments, each starting with the prefix "hepato" to indicate that it connects to the liver at one end. Most sources divide it into two parts: (, ) * hepatogastric ligament: the portion connecting to the lesser curvature of the stomach *

: the portion connecting to the duodenum In some cases, the following ligaments are considered part of the lesser omentum: *

hepatophrenic ligament The Hepatophrenic ligament is a ligament connecting the liver to the diaphragm. It is sometimes considered part of the lesser omentum. It is also sometimes considered part of the coronary ligament The coronary ligament of the liver refers to ...

: the portion connecting to the

thoracic diaphragm The thoracic diaphragm, or simply the diaphragm ( grc, διάφραγμα, diáphragma, partition), is a sheet of internal skeletal muscle in humans and other mammals that extends across the bottom of the thoracic cavity. The diaphragm is the m ...

* hepatoesophageal ligament: the portion connecting to the

esophagus The esophagus (American English) or oesophagus (British English; both ), non-technically known also as the food pipe or gullet, is an organ in vertebrates through which food passes, aided by peristaltic contractions, from the pharynx to t ...

- "Abdominal Cavity: The Lesser Omentum" * hepatocolic ligament: the portion connecting to the colon

Between the two layers of the lesser omentum, close to the right free margin, are the hepatic artery proper, the common bile duct, the

portal vein The portal vein or hepatic portal vein (HPV) is a blood vessel that carries blood from the gastrointestinal tract, gallbladder, pancreas and spleen to the liver. This blood contains nutrients and toxins extracted from digested contents. Approx ...

, lymphatics, and the hepatic plexus of nerves—all these structures being enclosed in a fibrous capsule ( Glisson's capsule). Between the layers of the lesser omentum, where they are attached to the stomach, run the right and left gastric arteries, as well as the gastric veins.

Additional images

File:Gray990.png, Diagrams to illustrate the development of the greater omentum and transverse mesocolon. File:Gray1039.png, Horizontal disposition of the peritoneum in the upper part of the abdomen.

References

External links

* * * * - "The stomach and lesser omentum." * - "Abdominal Cavity: The Lesser Omentum" * - "Stomach, Spleen and Liver: Contents of the Hepatoduodenal Ligament" * * * {{Authority control Abdomen

Structure

Divisions

Contents

Additional images

See also

References

External links