This document provides an overview of the anatomy and functions of the peritoneum, mesentery, and omentum. It describes: 1) The peritoneum is the largest serous membrane in the body, consisting of parietal and visceral layers. It has functions including pain perception, lubrication, and immune responses. 2) The peritoneal cavity contains serous fluid and is divided into recesses like the greater and lesser sacs. Various organs are located in the retroperitoneum. 3) Peritonitis is inflammation of the peritoneal cavity that can be localized or generalized. It has many causes including perforations, infections, and trauma. Diagnosis involves signs of pain and

1. PERITONEUM,
MESENTRY &
OMENTUM

2. ANATOMY
Overview-Abdominal Cavity
Boundaries
Superior- Thoracic aperture
& Diaphragm
Inferior- Pelvic brim

3. CONTENTS
•Major elements of the gastrointestinal system-
•The caudal end of the oesophagus, stomach, small and
large intestines, liver, pancreas, and gallbladder;
•The spleen;
•Components of the urinary system-kidneys and ureters;
•The suprarenal glands;
•Major neurovascular structures

5. PERITONIUM
Largest serous membrane in the body
Males-closed sac
Females-open at the lateral ends of the uterine tubes
Single layer of flat mesothelial cells lying on a layer of loose
connective tissue
Submesothelial connective tissue contain- Macrophages,
lymphocytes, adipocytes, fibroblasts

6. Two layers- PARIETAL, VISCERAL
Parietal and visceral peritoneum develop from the
somatopleural and splanchnopleural layers respectively of
lateral plate mesoderm
Somatic nerves that innervate the parietal peritoneum also
supply the corresponding segmental areas of skin and
muscles; when the parietal peritoneum is irritated, muscles
tend to contract reflexly, causing localized hypercontractility
(guarding) or even rigidity of the abdominal wall
The visceral peritoneum is innervated by branches of
visceral afferent nerves which travel with the autonomic
supply to the underlying viscera

7. FUNCTIONS OF THE
PERITONEUM
■ Pain perception (parietal peritoneum)
■ Visceral lubrication
■ Fluid and particulate absorption
■ Inflammatory and immune responses
■ Fibrinolytic activity

8. PERITONEAL CAVITY
Potential space between the parietal peritoneum, which lines
the abdominal wall, and infoldings of visceral
peritoneum, which suspend the abdominal viscera within the
cavity
Small amount of serous fluid- lubricates the visceral
peritoneum and allows the mobile viscera to glide freely on
the abdominal wall and each other.
Never contains gas in normal circumstances

9. PARTS OF CAVITY
greater sac
omental bursa

10. Subphrenic
Right Subhepatic
Lesser sac
Supramesocolic
Lesser sac Subphrenic
Left
Greater sac Perihepatic
Right
Inframesocolic Left
Paracolic
gutters

11. EPIPLOIC FORAMEN
(OF WINSLOW)
Short, vertical slit, usually 3 cm in height in adults, in the
upper part of the right border of the lesser sac
It leads into the greater sac

13. RECESSES OF THE
PERITONEAL CAVITY
These are of clinical interest because a length of intestine
may enter one and be constricted by the fold at the entrance
to the recess: it may subsequently become a site of internal
herniation
Duodenal recesses
Caecal recesses
Intersigmoid recess

14. DUODENAL RECESSES
Superior duodenal recess
Inferior duodenal recess
Paraduodenal recess
Retroduodenal recess

15. CAECAL RECESSES
Superior ileocaecal recess
Inferior ileocaecal recess
Retrocaecal recess

17. RETROPERITONEUM
Ascending Colon,
Descending Colon,
Duodenum,
Kidneys,
Suprarenals,
Pancreas,
Inferior Vena Cava
Abdominal Aorta

18. PELVIC PERITONEUM

19. PERITONITIS
Peritonitis is defined as inflammation of the peritoneal cavity,
where the peritoneal fluid increases in volume with the
passage of a transudate rich in leucocyte polymorphs and
fibrin.
Initially, peritoneal inflammation is often localized
If the inflammatory focus is part of an ongoing process, or if
host defences are lowered, localized peritonitis may progress
to life-threatening generalized peritonitis
Massive exudation of inflammatory fluid into the peritoneal
cavity causing hypovolaemia, often compounded by
toxaemia from absorbed products and septicaemia if
infection is present

20. SIGNS AND
SYMPTOMS
Poorly localized pain
Localization of the pain
Associated symptoms include malaise, nausea and vomiting,
and a low-grade fever
The four cardinal signs of peritonitis, consisting of
tenderness, guarding, rigidity, and rebound tenderness
Generalized-patient is clearly unwell, with marked fever,
dehydration, and absent bowel sounds

21. HIPPOCRATIC FACIES
In late generalised peritonitis,
circulatory failure ensues, with
cold, clammy extremities, sunken
eyes, dry tongue, thready
(irregular) pulse and drawn and
anxious face

22. AETIOLOGY OF
PERITONITIS
Acute peritonitis Chronic (sclerosing) peritonitis
Primary (spontaneous) Infectious
Secondary Drug-induced
Acute suppurative Chemical
Granulomatous Foreign-body
Chemical (aseptic) Carcinomatosis
Interventional
Traumatic
Drug-induced

23. PRIMARY
(SPONTANEOUS)
PERITONITIS
1 per cent of all cases of peritonitis
no obvious source for the peritoneal infection can be
demonstrated
diagnosis by exclusion and is confirmed in retrospect when
the results of blood cultures or peritoneal swabs become
available
haemolytic streptococci, Escherichia coli, pneumococci and
Klebsiella
Successful treatment of primary peritonitis, without resorting
to laparotomy or laparoscopy, is rare. Only when the
peritoneal tap and culture of peritoneal fluid reveals a non-
enteric organism can conservative antibiotic therapy be
instituted with caution

24. ACUTE SUPPURATIVE
PERITONITIS
This is the most common form of peritonitis encountered by
the surgeon
Perforation of a viscus (e.g. Appendix, peptic ulcer, colonic
diverticulum, or gallbladder),
Ischaemia of an intra-abdominal organ (e.g. Strangulated
hernia, volvulus, mesenteric artery occlusion),
Extension of an existing infection of an abdominal organ (e.g.
Appendix abscess, liver abscess, pyosalpinx).

26. MANAGEMENT OF
PERITONITIS
General care of patient:
■ Correction of fluid and electrolyte imbalance
■ Insertion of nasogastric drainage tube
■ Broad-spectrum antibiotic therapy
■ Analgesia
■ Vital system support
Operative treatment of cause when appropriate with
peritoneal debridement/lavage

27. SYSTEMIC
COMPLICATIONS OF
PERITONITIS
■ Bacteraemic/endotoxic shock
■ Bronchopneumonia/respiratory failure
■ Renal failure
■ Bone marrow suppression
■ Multisystem failure

28. ABDOMINAL
COMPLICATIONS OF
PERITONITIS
■ Adhesional small bowel obstruction
■ Paralytic ileus
■ Residual or recurrent abscess
■ Portal pyaemia/liver abscess

29. FAMILIAL MEDITERRANEAN
FEVER
(PERIODIC PERITONITIS)
The duration of an attack is 24–72 hours, when it is followed
by complete remission, but exacerbations recur at regular
intervals
This disease, often familial, is limited principally to Arab,
Armenian and Jewish populations; other races are
occasionally affected
Mutations in the MEFV (Mediterranean fever) gene appear to
cause the disease

30. BILIARY PERITONITIS
■ Perforated cholecystitis
■ Post cholecystectomy:
Cystic duct stump leakage
Leakage from an accessory duct in the gall bladder bed
Bile duct injury
T-tube drain dislodgement (or tract rupture on removal)
■ Following other operations/procedures:
Leaking duodenal stump post gastrectomy
Leaking biliary–enteric anastomosis
Leakage around percutaneous placed biliary drains
■ Following liver trauma

31. TUBERCULOUS
PERITONITIS
■ Acute and chronic forms
■ Abdominal pain, sweats, malaise and weight loss are
frequent
■ Caseating peritoneal nodules are common – distinguish
from metastatic carcinoma and fat necrosis of pancreatitis
■ Ascites common, may be loculated
■ Intestinal obstruction may respond to anti-tuberculous
treatment without surgery

32. Infection originates from:
• tuberculous mesenteric lymph nodes;
• tuberculosis of the ileocaecal region;
• a tuberculous pyosalpinx;
• blood-borne infection from pulmonary tuberculosis, usually
the ‘miliary’ but occasionally the ‘cavitating’ form
Varieties of tuberculous peritonitis:
Ascitic, Encysted, Fibrous, Purulent.

33. NEOPLASMS OF THE
PERITONEUM
Carcinoma peritonei
Common terminal event in many cases of carcinoma
ofthe stomach, colon, ovary or other abdominal organs and
also of the breast and bronchus
The main forms of peritoneal metastases are:
• discrete nodules – by far the most common variety;
• plaques varying in size and colour;
• diffuse adhesions – this form occurs at a late stage of the
diseaseand gives rise, sometimes, to a ‘frozen pelvis’.
Treatment-Ascites caused by carcinomatosis of the
peritoneum may respondto systemic or intraperitoneal
chemotherapy or to endocrine therapy

34. Pseudomyxoma peritonei
Associated with mucinous cystic tumours of the
ovary and appendix, abdomen is filled with a yellow jelly,
large quantities of which are often encysted
Rx-recurrence is inevitable, but patients may gain
symptomatic benefit from repeated ‘debulking’ surgery
Mesothelioma
Desmoid

35. OMENTA
The omenta consist of two layers of peritoneum, which pass
from the stomach and the first part of the duodenum to other
viscera. There are two:
the greater omentum derived from the dorsal mesentery;
the lesser omentum derived from the ventral mesentery

36. GREATER OMENTUM
The greater omentum is a large, apron-like, peritoneal fold
that attaches to the greater curvature of the stomach and the
first part of the duodenum.
It drapes inferiorly over the transverse colon and the coils of
the jejunum and ileum
It is often referred to as the 'policeman of the abdomen'
because of its apparent ability to 'migrate' to any inflamed
area and wrap itself around the organ to 'wall off'
inflammation

38. LESSER OMENTUM
Two-layered peritoneal
omentum is the lesser
omentum.
It extends from the lesser
curvature of the stomach
and the first part of the
duodenum to the inferior
surface of the liver

39. TORSION OF THE
OMENTUM
Defined as a rotation of the organ in its longitudinal access
around a narrow pedicle
Primary-Predisposing factors include an anatomical
abnormality-bifid omentum, accessory omentum, and a
narrowed omental pedicle
Secondary(more common)-The omentum twists between two
fixed points and its distal edge is attached directly or by
adhesions to cysts, tumours (primary or secondary), foci of
intra-abdominal inflammation, post-surgical wounds or
scarring, internal hernia, or external hernial sacs.

41. TUMOURS OF THE
OMENTUM
Omental cysts
Cystic lymphangioma
Cystic mesothelioma
Dermoid cysts
Pseudocysts
Solid tumours of the omentum
Secondary tumour
Primary tumour- fibroma, fibrosarcoma, lipoma, and
liposarcoma

42. MESENTERY
The mesentery is a large, fan-shaped, double-layered fold of
peritoneum that connects the jejunum and ileum to the
posterior abdominal wall
Its superior attachment is at the duodenojejunal junction, just
to the left of the upper lumbar part of the vertebral column. It
passes obliquely downward and to the right, ending at the
ileocecal junction near the upper border of the right
sacroiliac joint.
In the fat between the two peritoneal layers of the mesentery
are the arteries, veins, nerves, and lymphatics that supply the
jejunum and ileum.

43. Transverse mesocolon
Sigmoid mesocolon
Mesoappendix
Ligaments-example, the
splenorenal ligament connects the
left kidney to the spleen and the
gastrophrenic ligament connects
the stomach to the diaphragm

44. MESENTERIC INJURY
Blunt trauma to the abdomen causes mesenteric injury in
approx. 5 per cent of all patients
Results in mesenteric hematomas, free intraperitoneal
hemorrhage, or devascularization of the bowel causing
ischemia
Penetrating trauma causes lacerations-injury to a large
mesenteric-root vessel or extensive combined bowel and
mesenteric disruption
Seatbelt syndrome-sudden deceleration can result in a torn
mesentery

46. DIAGNOSTIC
PERITONEAL LAVAGE
Under local anaesthesia, a subumbilical incision is made
down to the peritoneum in a similar way to that used for
‘open’ laparoscopy. A purse-string suture is placed in the
peritoneum, which is then incised. Free fluid, e.g. blood or
intestinal contents, may be found but, if not, a peritoneal
dialysis catheter is inserted and the purse-string suture tied.
A litre of normal saline is run into the peritoneum and then
drained off by placing the bag and tubing below the patient’s
abdomen.

48. THANK YOU