PERITONEAL SPACES AND RECESSES BY DR. A.PERVEZ MS (GEN.SURGERY)

CONTENTS INTRODUCTION PERITONEAL FOLDS PERITONEAL COMPARTMENTS SUPRACOLIC COMPARTNENT LESSER SAC INFRACOLIC COMPARTMENT RETROPERITONEAL SPACE PERITONEAL RECESSES APPLIED ANATOMY

INTRODUCTION Serous membrane lining the abdominal cavity Comprises of 2 layers i.e parietal peritoneum and visceral peritoneum. Consists of a single layer of flattened cells with phagocytic properties,overlying areolar tissue which varies in thickness and density. Various peritoneal reflections connect viscera to the abdominal walls or to one another( a.k.a folds,mesentery,ligament or omentum).

PERITONEAL FOLDS OF ANTERIOR ABDOMINAL WALL On the posterior surface of the anterior abdominal wall,the peritoneum is raised into 6 folds. 1.Falciform ligament 2.Median umbilical fold containing median umbilical ligament centrally. 3.Medial umbilical fold containing medial umbilical ligament on each side. 4.Lateral umbilical fold containing inferior epigastric vessels on each side.

PERITONEAL COMPARTMENTS Peritoneal cavity is descriptively divide into supracolic,infracolic & pelvic compartments. Dividing line between supra & infracolic compartments is the transverse mesocolon. Attachments of liver to diaphragm & abdominal wall define the subdivisions of the supracolic compartment. The infracolic compartment is divided further by the root of the mesentery.

On either side of the median umbilical fold (i On either side of the median umbilical fold (i.e between median & medial folds) there are depressions called SUPRAVESICAL FOSSAE. Between the medial & the lateral umbilical folds are depressions called MEDIAL INGUINAL FOSSAE. Lateral to the lateral folds are the LATERAL INGUINAL FOSSAE. On either side of the urinary bladder are the PARAVESICAL FOSSAE.

SUPRACOLIC COMPARTMENT To the right & left of the falciform ligament are the RIGHT & LEFT SUBPHRENIC(subdiaphragmatic) spaces. They are closed above by superior layer of coronary ligament & anterior layer of left triangular ligament. Behind the right lobe of liver & in front of the right kidney is the RIGHT SUBHEPATIC space or Morrison’s hepatorenal pouch.

This space is closed above by the inferior layer of coronary ligament & right triangular ligament. To its right is the diaphragm & on the left the space communicates with the lesser sac or LEFT SUBHEPATIC through the epiploic foramen. Below it’s continuous with the right paracolic gutter. On lying supine the hepatorenal pouch is the lowest part of the peritoneal cavity and is a likely area of intraperitoneal fluid accumulation.

LESSER SAC It’s a large recess of the peritoneal cavity that communicates with the main cavity or greater sac through foramen epiploicum. Upper part of the posterior wall of the lesser sac is formed by peritoneum lining structures on the posterior abdominal wall. Lower part of the posterior wall is formed by posterior 2 layers of the greater omentum. Lower border of the lesser sac is formed by the anterior 2 layers of the greater omentum

The right side of its upper border is formed by peritoneal reflection from upper end of caudate lobe of liver. To the left of the caudate lobe the lesser sac is formed by reflection of peritoneum from upper part of fundus of stomach. The left border is formed by the gastrosplenic and leinorenal ligaments. Left border is formed by the continuity of anterior&posterior layers of greater omentum.

INFRACOLIC COMPARTMENT To the right of the root of mesentery is the triangular RIGHT INFRACOLIC space. Its apex lies at the ileocaecal junction. It’s right side is the ascending colon & it’s base is the attachment of transverse mesocolon. Lateral to ascending colon is the RIGHT PARACOLIC gutter which can be traced upwards into the hepatorenal pouch and downwards into the pelvis. The LEFT INFRACOLIC is larger than its right counterpart.

Its quadrilateral shaped & widens below where its continuous across the pelvic brim. It’s upper border is the transverse mesocolon attachment & to its left is the descending colon. Lateral to the descending colon is the LEFT PARACOLIC gutter. It’s limited above by the phrenico-colic ligament. Traced downwards this gutter leads to attachment of lateral limb of sigmoid mesocolon. There is a midline extraperitoneal space called as the BARE AREA OF LIVER. It’s present between both layers of the coronary ligament and the IVC lies to it’s left

RETROPERITONEAL SPACE Major structures lie on the posterior abdominal wall behind the peritoneum. These include aorta,IVC,cysterna chyli,urogenital system,ascending&descending colon to name a few. All the above are said to lie in the RETROPERITONEAL space. Any hemorrhage or pus can get confined here.

PERITONEAL RECESSES The largest recess is the lesser sac but there are other such recesses in the peritoneum. SUPERIOR DUODENAL RECESS INFERIOR DUODENAL RECESS PARADUODENAL RECESS RETRODUODENAL RECESS DUODENUJEJUNAL RECESS MESENTEROPARIETAL RECESS

SUPERIOR ILEOCAECAL RECESS INFERIOR ILEOCAECAL RECESS RETROCAECAL RECESS Sometimes a recess may be present deep to the apex of the sigmoid mesocolon and its related to left ureter & left common iliac artery.

CLINICAL CORRELATIONS OF THE PERITONEUM Peritoneal fluid is not static but circulates through the peritoneal cavity and gets replaced. The flow is upward towards the diaphragm. This principle is used to for peritoneal dialysis. Under certain conditions there is increase in the quantity of peritoneal fluid called ascitis. This ascitic fluid can be drained by placing a cannula in the peritoneum through the abdominal wall by a procedure called paracentesis.

The large absorptive area of the peritoneum poses a serious danger when infection develops in the peritoneum (peritonitis). The parietal peritoneum has a rich supply of somatic nerves so inflammation makes it very sensitive to stretching.This forms the basis for a clinical test called rebound tenderness. Infection can occur in any of the subphrenic spaces described earlier.

The right subhepatic space which is the most dependent part of the peritoneal cavity is the most commonest site of a subphrenic abscess and infection can spread to gallbladder or appendix from here. Pain arising from a subdiaphragmatic infection can radiate to the shoulder (phrenic N c3,4,5). Accumulation of fluid in the lesser sac is a complication of pancreatitis & leads to formation of pseudocyst.

Peritoneum on the front of rectum reflected on to the uppermost part of the vagina is called rectouterine pouch(pouch of douglas) which becomes the most dependent part of the peritoneal cavity. This area is accessible either through rectum or posterior fornix of vagina. In the male it is replaced by the rectovesical pouch.

The procedure through which the peritoneal cavity is opened is called a laparotomy. This procedure is done as preliminary to abdominal surgery or used to inspect the interior of the abdominal cavity where diagnosis is difficult. The above may also be carried out via a minimal access procedure called laparoscopy.

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