Peritoneal cavity- lesseer sac & greater sac

PERITONEAL CAVITY

• Peritoneal cavity is the potential space b/w parietal & visceral layers & is filled with serous peritoneal fluid.
• Subdivided into:  LESSEER SAC & GREATER SAC    

LESSEER SAC (Omental bursa)

• Also c/d omental bursa or left subhepatic space or left posterior intraperitoneal space.
• It is a deep peritoneal space lying behind the stomach, lesser omentum & liver (caudate lobe).
• Site for abscess formation in posterior perforation of gastric ulcer and internal hernia through epiploic foramen.
• It is a closed space except for its communication on right side with greater sac through epiploic foramen.

Boundaries of lesser sac are:

1. Anterior wall:  Caudate lobe of liver, stomach, Lesser omentum & 2nd layer of greater omentum
2. Posterior wall: 3rd layer of greater omentum, & structurres forming stomach bed 
3. Right border: Right free margin of greater omentum & floor of epiploic foramen.
4. Left border: Left free mergin of greater omentum; gastrosplenic & gastrophrenic ligaments
5. Upper border: Reflection of peritoneum from esophagus to diaphragm.
6. Lower border: Continuation of 2nd & 3rd layers of greater omentum.

Epiploic foramen (foramen of winslow or aditus to lesser sac) is a slit-like opening through which lesser sac communicates with greater sac.

• The foramen is about 3 cm in size and situated opposite the 12th thoracic vertebra.

Boundaries are:

• Anterior: Right free margin of lesser omentum (contains portal vein, hepatic artery proper & bile duct).
• Posterior: IVC, right suprarenal gland & T12 vertebra
• Superior: Caudate lobe of liver
• Inferior: 1st part of duodenum & horizontal part of hepoatic artery

1. → A posterior gastric ulcer may perforate into lesser sac. The leaking fliud passes out through epiploic foramen to reach hepatorenal pouch.
2.  →  Site for abscess formation in posterior perforation of gastric ulcer and internal hernia through epiploic foramen.

 GREATER SAC

Greater sac is divided by line of attachment of transverse mesocolon & pelnic brim into 3 parts:

1. Supracolic (above transverse mesocolon)
2. Infracolic (below transverse mesocolon upto pelvic brim)
3. Pelvic (below pelvic brim)

Exam Question

• The length of the epiploic foramen is 3 cm.
• Epiploic foramen provides communication between greater and lesser sacs.
• A posterior gastric ulcer may perforate into lesser sac.
• Omental bursa is site for abscess formation in posterior perforation of gastric ulcer and internal hernia through epiploic foramen.

Boundaries of lesser sac are:

1. Anterior wall:  Caudate lobe of liver, stomach, Lesser omentum & 2nd layer of greater omentum
2. Posterior wall: 3rd layer of greater omentum, & structurres forming stomach bed 
3. Right border: Right free margin of greater omentum & floor of epiploic foramen.
4. Left border: Left free mergin of greater omentum; gastrosplenic & gastrophrenic ligaments
5. Upper border: Reflection of peritoneum from esophagus to diaphragm.
6. Lower border: Continuation of 2nd & 3rd layers of greater omentum.