Serous membrane with single layer of flat mesothelial cells (with phagocytic properties).
Parietal peritoneum attached to abdominal walls by areolar tissue of variable density.
- loose and cellular where expansile, eg lower abdominal wall
- non-expansile areas are thick: eg iliac, psoas, parietal pelvic fascia.
- Either way they are part of the same continuous experitoneal c.t.
One above, five below umbilicus:
(1) Falciform ligament Ð connects liver to abdo wall and inferior
diaphragmatic surface
- concave inferior margin contains the ligamentum teres, deviates to right.
(2) Median umbilical fold (containing remnant of urachus)
(3) 2 Medial umbilical folds (containing obliterated umb arteries, also run to umbilicus)
(4) 2 Lateral umbilical folds (containing inferior epigastric vessels; do not reach umbilicus)
- the abdominal ligaments are merely folds with organs attached to them.
Greater sac: general peritoneal cavity
Lesser sac: (omental bursa) diverticulum of greater sac,
- neck = epiploic foramen of Winslow. lies in front of IVC,
- anterior wall = posterior of lesser omentum, posterior stomach and the posterior of the anterior 2 layers of the greater omentum.
- Posterior wall = anterior of the two posterior layers of greater omentum, transverse colon / mesocolon, pancreas, L kidney, L adrenal, abdo aorta, coeliac artery and part of diaphragm (see 267)
- Upper border = right side of oesophagus, where peritoneal wall reflected
- Left border = lienorenal and gastrosplenic ligaments (see 256)
Double sheet of peritoneum folded on itself in four layers:
Anterior 2 layers
form from peritoneum over stomach, meet at greater curve , then head to
anterior surface of transverse colon as gastrocolic omentum.
- R and L gastroepiploic vessels run between the layers, close to greater curvature
- This is a popular route to access the lesser sac operatively
- the anterior layer also envelopes the spleen at its left border (which hangs into abdominal cavity by its hilum
Posterior 2 layers are folds from the retroperitoneum, fuse with anterior layers below transverse colon
The gastrosplenic and leinorenal ligaments (see 256) are double folds of peritoneum that connect spleen with stomach and left kidney respectively.
- Pancreatic tail and splenic vessels lie in the lienorenal
- Short gastric and left gastroepiploic run in gastrosplenic
AKA the gastrohepatic omentum: connects right oesophagus and lesser curvature, first 2cm duodenum to the fissure for ligamentum venosum and porta hepatis (L-shaped attachment to liver Ð see Pl 270)
- epiploic foramen of Winslow is a 2.5cm vertical slit in right border of lesser sac
- upper boundary is the caudate lobe of the liver
- lower is D1
- posterior is IVC
- anterior is the right free margin with portal vein, hepatic artery and CBD, with nerves, lymph.
It is 2 layers of peritoneum: upwards they split to cover the liver, then diaphragm / anterior abdo wall as the coronary, triangular and falciform ligaments. (the liver ÔhangsÕ off these Ð see Pl 270
Divided into infra- & supracolic by transverse mesocolon which attaches posteriorly (R ¨ L) to lower pole of R kidney, D2, pancreas, lower pole of L kidney.
- transverse mesocolon is adherent to posterior surface of greater omentum
Divided into R & L subphrenic spaces by falciform ligament.
- these closed in above by coronary ligament on R and left triangular ligament on L
- this is continuous below with the right paracolic gutter
- fluid will accumulate here when supine as it becomes ~lowest point of abdomen (except pelvis)
- depth of mesentry is greatest centrally at 20cm
- Pacinian corpuscles in root of mesentry drop BP if stimulated by tension / traction
R infracolic compartment (triangular) lies between asc colon, trans colon, and root of mesentery.
- contains lower pole of R kidney, D2 , D3. (see 257)
L infracolic compartment (quadrilateral) lies between desc colon, root of mesentry, trans colon and is continuous with the pelvic cavity across the pelvic brim (see 257)
-
contains D4, paraduodenal recess, lower pole of L kidney.
L paracolic gutter commences in infracolic compartment below phrenicocolic ligament (has to be divided to mobilise the splenic flexure Ð see 257) & leads down into pelvis beside base of sigmoid mesocolon.
R paracolic gutter begins in supracolic compartment at hepatorenal pouch of Morison & runs into pelvis.
Note sigmoid mesocolon attachment: at its apex is the left ureter, with inferior mesenterics medial and vein lying between ureter and artery (257)
- may need to divide congenital adhesion between pelvic mesocol and parietal peritoneum at floor of LIF
Pain from viscera may be from ischaemia, tension on folds, parietal peritoneum, or muscle spasm.
Peritoneum Ð supplied segmentally by spinal nerves supplying overlying muscles.
- eg diaphragmatic peritoneum supplied by C4 so that pain may go to shoulder
- rest is by intercostal and lumbar nerves / obturator nerve in pelvis.
Area of posterior abdominal wall behind peritoneum.
Haemorrhage, infection, blood and pus can sit here.