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    Related Topics

    From Digestive System

    Major Duodenal Papilla
    Opening for bile and pancreatic ducts into duodenum.
    Body of Pancreas
    Central elongated portion of pancreas.
    Soft Palate
    Muscular posterior part of the roof of the mouth.
    Oral Cavity
    Entry point of the digestive system; includes teeth, tongue, and salivary openings.
    Parotid Glands
    Largest salivary glands located near the ear.
    Esophagus
    Muscular tube conveying food from the pharynx to the stomach.
    Left Lobe
    Smaller lobe of the liver.
    Internal Anal Sphincter
    Involuntary muscle around anal canal.
    Mesocolon
    Peritoneal fold attaching colon to posterior wall.
    Body
    Main central region of the stomach.
    Epiploic Appendages
    Fat-filled pouches attached to colon.
    Cystic Duct
    Connects gallbladder to common bile duct.
    Gallbladder
    Stores and concentrates bile.
    Ileum
    Final and longest portion of the small intestine.
    Minor Duodenal Papilla
    Opening for accessory pancreatic duct.
    Rugae of Stomach
    Internal folds allowing expansion of the stomach.
    Anus
    Opening through which feces are expelled.
    Haustra
    Pouch-like segments of colon.
    Falciform Ligament
    Connects liver to anterior abdominal wall.
    Quadrate Lobe
    Small lobe located between gallbladder and round ligament.
    Laryngopharynx
    Lower part of pharynx leading to esophagus.
    Head of Pancreas
    Widest part of pancreas nestled in duodenum.
    Ligamentum Venosum
    Remnant of ductus venosus in liver.
    Cecum
    First part of large intestine.
    Duodenal Bulb
    Initial section of duodenum closest to the stomach.

    Greater Omentum

    Reviewed by our medical team

    Fatty fold of peritoneum covering intestines.

    Overview

    The greater omentum is a large, apron-like fold of peritoneum that hangs down from the greater curvature of the stomach and drapes over the intestines. It plays a critical role in immune defense, fat storage, infection containment, and maintaining abdominal organ stability. Although it is not directly involved in digestion, it is vital for protecting and supporting abdominal viscera.

    Location

    The greater omentum is located in the anterior abdominal cavity. It:

    • Arises from the greater curvature of the stomach and the proximal duodenum

    • Hangs down like an apron in front of the small intestines (especially the jejunum and ileum)

    • Loops back and attaches to the transverse colon and its associated mesocolon

    It occupies the space between the anterior abdominal wall and the underlying intestinal loops.

    Structure

    The greater omentum is composed of:

    • Four layers of peritoneum: Two anterior and two posterior layers that fuse during development

    • Fat tissue: Variable amounts of adipose tissue stored between the peritoneal layers

    • Blood vessels: Supplied primarily by the right and left gastroepiploic arteries and veins

    • Lymphatics: Numerous lymph nodes embedded in the fat for immune surveillance

    The omentum is highly mobile and can migrate toward sites of infection or injury in the peritoneal cavity, earning it the nickname "policeman of the abdomen."

    Function

    The greater omentum serves several important functions:

    • Immune surveillance: Contains macrophages and lymphocytes that monitor and respond to infection or inflammation

    • Fat storage: Acts as a depot for energy storage and insulation

    • Protection: Cushions the abdominal organs from trauma

    • Infection containment: Physically walls off areas of infection or perforation (e.g., in appendicitis or diverticulitis)

    Physiological Role(s)

    Though not directly digestive, the greater omentum contributes to abdominal physiology by:

    • Immune modulation: Lymphoid aggregates in the omentum help regulate peritoneal immune responses

    • Vascular support: Provides collateral blood flow to the stomach and colon through its arterial network

    • Tissue repair: Aids in healing damaged or inflamed peritoneal tissues

    • Peritoneal fluid absorption: Assists in maintaining fluid balance within the peritoneal cavity

    Clinical Significance

    The greater omentum is involved in several clinical contexts:

    • Omental infarction: A rare condition where omental tissue becomes ischemic due to torsion or vascular compromise, mimicking appendicitis

    • Adhesions and omental wrapping: The omentum may adhere to inflamed organs, sometimes protecting them but also contributing to postoperative adhesions

    • Tumor spread (omentum cake): Metastatic cancer, particularly from ovarian, gastric, or colon cancer, can spread to and thicken the omentum, creating a radiologic sign called an “omental cake”

    • Omentectomy: Surgical removal of the omentum, often performed in oncologic surgeries to remove metastatic deposits

    • Transplantation and grafting: Due to its rich vascular and immune properties, the omentum has been used experimentally in grafting procedures to promote healing

    Imaging techniques like ultrasound, CT scan, and laparoscopy can be used to visualize the greater omentum, especially in cases of inflammation, tumors, or fluid accumulation.

    Did you know? Your digestive system works continuously, even when you are not eating, by processing food and waste.