| Lesser omentum | |
|---|---|
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| Details | |
| Identifiers | |
| Latin | omentum minus |
| TA98 | A10.1.02.101 |
| TA2 | 3750 |
| FMA | 9715 |
| Anatomical terminology | |
The lesser omentum (small omentum or gastrohepatic omentum) is the double layer of peritoneum that extends from the liver to the lesser curvature of the stomach, and to the first part of the duodenum. The lesser omentum is usually divided into these two connecting parts: the hepatogastric ligament, and the hepatoduodenal ligament. [1]
The lesser omentum is extremely thin, and is continuous with the two layers of peritoneum 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.
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: [1]
In some cases, the following ligaments are considered part of the lesser omentum:
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, 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.
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 organs, and is composed of a layer of mesothelium supported by a thin layer of connective tissue. This peritoneal lining of the cavity supports many of the abdominal organs and serves as a conduit for their blood vessels, lymphatic vessels, and nerves.
The abdominal cavity is a large body cavity in humans and many other animals that contains many organs. It is a part of the abdominopelvic cavity. It is located below the thoracic cavity, and above the pelvic cavity. Its dome-shaped roof is the thoracic diaphragm, a thin sheet of muscle under the lungs, and its floor is the pelvic inlet, opening into the pelvis.
The mesentery is an organ that attaches the intestines to the posterior abdominal wall and is formed by the double fold of peritoneum. It helps in storing fat and allowing blood vessels, lymphatics, and nerves to supply the intestines, among other functions.
In human anatomy, the left gastric artery arises from the celiac artery and runs along the superior portion of the lesser curvature of the stomach before anastomosing with the right gastric artery. It also issues esophageal branches that supply lower esophagus and ascend through the esophageal hiatus to form anastomoses with the esophageal branches of thoracic part of aorta.
The lesser sac, also known as the omental bursa, is a part of the peritoneal cavity that is formed by the lesser and greater omentum. Usually found in mammals, it is connected with the greater sac via the omental foramen or Foramen of Winslow. In mammals, it is common for the lesser sac to contain considerable amounts of fat.
In human anatomy, the greater sac, also known as the general cavity (of the abdomen) or peritoneum of the peritoneal cavity proper, is the cavity in the abdomen that is inside the peritoneum but outside the lesser sac.
The hepatic artery proper is the artery that supplies the liver and gallbladder. It raises from the common hepatic artery, a branch of the celiac artery.
The right gastroepiploic artery is one of the two terminal branches of the gastroduodenal artery. It runs from right to left along the greater curvature of the stomach, between the layers of the greater omentum, anastomosing with the left gastroepiploic artery, a branch of the splenic artery.
The left gastroepiploic artery, the largest branch of the splenic artery, runs from left to right about a finger's breadth or more from the greater curvature of the stomach, between the layers of the greater omentum, and anastomoses with the right gastroepiploic.
The right gastric artery usually arises from the proper hepatic artery. It descends to the pyloric end of the stomach before passing from right to left along its lesser curvature, supplying it with branches, and finally anastomosing with the left gastric artery.
The foregut in humans is the anterior part of the alimentary canal, from the distal esophagus to the first half of the duodenum, at the entrance of the bile duct. Beyond the stomach, the foregut is attached to the abdominal walls by mesentery. The foregut arises from the endoderm, developing from the folding primitive gut, and is developmentally distinct from the midgut and hindgut. Although the term “foregut” is typically used in reference to the anterior section of the primitive gut, components of the adult gut can also be described with this designation. Pain in the epigastric region, just below the intersection of the ribs, typically refers to structures in the adult foregut.
The greater omentum is a large apron-like fold of visceral peritoneum that hangs down from the stomach. It extends from the greater curvature of the stomach, passing in front of the small intestines and doubles back to ascend to the transverse colon before reaching to the posterior abdominal wall. The greater omentum is larger than the lesser omentum, which hangs down from the liver to the lesser curvature. The common anatomical term "epiploic" derives from "epiploon", from the Greek epipleein, meaning to float or sail on, since the greater omentum appears to float on the surface of the intestines. It is the first structure observed when the abdominal cavity is opened anteriorly.
The gastrocolic ligament is a portion of the greater omentum that stretches from the greater curvature of the stomach to the transverse colon. It forms part of the anterior wall of the lesser sac.
The suspensory ligament of the ovary, also infundibulopelvic ligament, is a fold of peritoneum that extends out from the ovary to the wall of the pelvis.
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.
The hepatogastric ligament or gastrohepatic ligament connects the liver to the lesser curvature of the stomach. It contains the right and the left gastric arteries. In the abdominal cavity it separates the greater and lesser sacs on the right. It is sometimes cut during surgery in order to access the lesser sac. The hepatogastric ligament consists of a dense cranial portion and the caudal portion termed the pars flaccida.
The paracolic gutters are peritoneal recesses – spaces between the colon and the abdominal wall.
The gastrosplenic ligament is part of the greater omentum extending between the stomach and the spleen. It contains several blood vessels.
The curvatures of the stomach refer to the long, convex, lateral suface and the shorter, concave, medial surface of the organ, which are referred to as the greater and lesser curvatures, respectively. The greater curvature, which begins at the cardiac notch, and arches backwards, passing inferiorly to the left, is four or five times as long as the lesser curvature, which attaches to the hepatogastric ligament and is supplied by the left gastric artery and right gastric branch of the hepatic artery.
In human anatomy, the omental foramen, is the passage of communication, or foramen, between the greater sac, and the lesser sac.
This article incorporates text in the public domain from page 1156 of the 20th edition of Gray's Anatomy (1918)
