1. OMENTUM – Anatomy,
Pathological conditions and
Surgical Importance

2. • OMENTUM is a fold of peritoneum
extending from the stomach to adjacent
abdominal organs.
• Aristotle (384-322 B.C.) described omentum
as a warm fatty material attached to
stomach which speeds digestion by its
warmth
• Rutherford Morison developed the concept
of the omentum as an "abdominal
policeman"

3. Anatomy
• Embryology of
peritoneum

4. • Omentum arises from
dorsal and ventral
mesenteries
• Stomach rotates by 90
degree to have lesser
curvature on right and
greater curvature on left
• Most of the ventral
mesentery is reabsorbed
the one persisting from
ligamentum venosum,
porta hepatis, proximal
duodenum and lesser
curvature is the lesser
omentum

5. Greater omentum develops from dorsal mesogastrium

6. Greater omentum
• The greater omentum is a
large 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 reflects on
itself to ascend to the
transverse colon before
reaching to the posterior
abdominal wall.

7. • Divided into two parts
• The gastrocolic ligament extends between the
first part of the duodenum and great curvature
of the stomach to the transverse colon. It
contains the right and left gastroepiploic
vessels
• The fat apron which hangs from the transverse
colon to the free peritoneal cavity

8. • Arterial supply -
right and left
gastroepiploic
arteries which
anastomose and
form the arc of
Barkow.
• Venous drainage
into portal system

9. • Lymphatics - two
draining pathways
1. subpyloric nodes
2. splenic nodes
• Some studies reported
communication between
the lymphatics of the
omentum and the
stomach
• Rich lymphatic vessels
help in removing
metabolic waste and
excess fluid, destroying
toxic substances, and
fighting disease.

10. Lesser omentum
• a double-layered entity suspended between the
lesser curvature of the stomach and the proximal
½ inch (2 cm) of the first part of the duodenum
inferiorly and the porta hepatis and the fissure of
the ligamentum venosum superiorly
• divided into two ligaments: the hepatogastric and
the hepatoduodenal
• Contains the hepatic triad, branches of the
anterior vagus nerve, some lymph nodes, and the
right and left gastric arteries.

11. Lesser sac or Omental bursa
• potential space behind the
stomach
• It is demarcated anteriorly
by the quadrate lobe of the
liver, the stomach, lesser
omentum and gastrocolic
ligament. Posteriorly it is
marked by the pancreas. Its
left lateral margin is made
by the left kidney and
adrenal gland. Its boundary
on the right is made by the
epiploic foramen and lesser
omentum

12. Epiploic foramen
• Also called foramen of Winslow
• found just below the neck of the
gallbladder.
• This foramen is bound anteriorly
by the right, free border of the
duodenohepatic ligament, the
fold forming the right termination
of the lesser omentum, between
the two layers of which are the
hepatic artery, the portal vein,
and the hepatic duct. It bound
posteriorly by the inferior vena
cava, which is covered by the
peritoneum. Superiorly, it is
bound by the caudate lobe of the
liver and inferiorly, by the first
portion of the duodenum and the
hepatic artery

13. Pathological conditions of Omentum
Omental cysts
• Etiology – obstructed
omental lymphatic channels
• Unilocular or Multilocular
• Asymptomatic or some times
mass palpable per abdomen
• Complications – Torsion,
Infracts & rupture
• Diagnosed by CT which
shows fluid filled, complex,
cystic mass with septations
• Treatment- local excision

14. Omental torsion and infraction
• Due to axial twisting along its long axis
• If twist is thight enough or venous obstruction is of
sufficient duration arterial in flow is compromised
leadind to infraction and necrosis
• Two type 1)Primary- No cause usually on right side
2)Secondary – associated with other
conditions like hernia, adhesions, tumors
• Common in men seen in 4th and 5th decades

15. • Symptoms – abdominal pain usually on right
side, nausea and vomiting in some cases
• o/e – localized abdominal tenderness,
guarding present
• Differential diagnosis – should be
differentiated from other rt sided abdominal
pain like acute appendicitis, cholecytitis and
twisted ovarian cysts
• Diagnosis is made by CT which shows omental
mass

16. • Treatment – laprotomy and resection of
involved omentum and correction of any
related conditions
• Omental neoplasms
• Usually rare and of soft tissue in origin
• Mostly metastasis that has spread
transperitoneally from intra-abdominal cancer

17. Functions of Omentum
• Deposition of fat in form of adipose tissue
• Immunity has milky spots which are macrophage
collections
• Isolation of wound and infection
• It limits intraperitoneal infection spread and are
many times found to encircle the concerned
areas of trauma or infection
• Edema Absorption - lymphatic system has an
enormous capacity to absorb edema fluid
• Stem cells

18. Clinical importance of Omentum
• Drainage – collection in
anterior aspect of
stomach is collected in
greater sac and
collection below liver is
collected in leesser sac
through epiploic
foramen
• Surgical approach to
retro peritoneum

19. • Division of either left or
right gastroepiploic
artery and vasa recta
along the greater
curvature of stomach
with mobilization of
omentum from
transverse colon allows
development of a
vascularised omental
pedicle flap

20. • Used to cover chest and mediastinal wounds
after chest wall resection
• Used to prevent small intestine from entering
pelvis after abdominal perineal resection thus
preventing radiation enterits due to radio
therapy for rectal cancer

21. • Formation of dense
adhesions between
omentum and sites of
perforation or
inflammation thus
facilitates use as patch
for duodenal
perforation for ulcer
disease known as
Graham patch

22. Thank you