L5.1 Peritoneal cavity

Question 1

What is the peritoneal cavity

Answer 1

• Potential space b/w parietal & visceral peritoneum; viscera suspended within coelom

Question 2

Parietal peritoneum

Answer 2

• Around body wall
• Receives same NS & BS as outer body wall (somatic N)
  
  • Sensation is localised → able to feel pain of parietal peritoneum on overlying dermatomes

Question 3

Visceral peritoneum

Answer 3

• within peritoneal caivty, covers viscera
• NS & BS same as viscera
• Refers pain to midline of dermatome

Question 4

Midline unpair peritoneal viscera

Answer 4

• Develops within peritoneum: i.e. GIT (starts beneath diaphragm) & associated organs

Question 5

Territory & supply of: Foregut

Answer 5

• Ab part of oesophagus, stomach, prox part of duodenum, liver/pancreas/spleen
• Celiac trunk
  
  • Refers pain to lower end of sternum (trans-pyloric pain)

Question 6

Territory & supply of: Midgut

Answer 6

• Distal end of duodenum, Jejunum+ileum, LI (until T.colon)
• SUP mesenteric vessels

Question 7

Territory & supply of: Hindgut

Answer 7

• D.colon + sigmoid colon, rectum, upper part of anal canal
• INF mesenteric vessels

Question 8

Laterally paired ab viscera

Answer 8

• Develop without peritoneum i.e: Urogenital tract & endocrine system
  
  • Kidneys & suprarenal glands, ureters, testes, deferent ducts
• Is retroperitoneal: b/w POS ab wall & parietal peritoneum (only on ANT side)
  
  • Fats separating viscera from parietal peritoneum

Question 9

Mesentery

Answer 9

• connects viscera to body walls
• Conveys NS & BS to viscera
• Ventral/dorsal

Question 10

Positional development of stomach, liver, spleen

Answer 10

• GI size exceeds space during dev → causes stomach to have CLOCKWISE rotation during growth of gut
  
  • Liver pushed to the R under diaphragm
  • Spleen pushed to the L & posteriorly

Question 11

Transition of intraperitoeanl to secondary retroperitoneal

Answer 11

• Mesentery of midgut (carries SMA on a A-P axis) undergoes COUNTERCLOCKWISE rotation during development
  
  • Duodenum forms C-shaped curve → meets jejunum&ileum → which then becomes convoluted
  • SI meets LI → forms upsidedown U
  • Structures pushed to POS ab wall → mesentery fused to POS wall
    
    • Becomes secondary retroperitoneal

Question 12

Secondary retroperitoneal structures

Answer 12

• Have a fixed mesentery
• Duodenum, pancreas, A colon, D colon, Anal canal

Question 13

Why is there an alternation of fixed and mobile GIT

Answer 13

• Allows GIT to distend & peristalsis to work
  
  • Allows movement of vis organs against fixed parts

Question 14

Fusion fascia

Answer 14

• Original peritoneum from secondary retroperitoneal structures fixed with POS wall, fusions b/w POS ab wall & mesentery
  
  • Particularly M-L walls of fixed LI
  • Have fixed mesentery

Question 15

Paracolic gutter

Answer 15

• Spaces b/w colon & ab wall
• Fixed parts of colon

Question 16

Mesenteries of the intraperitoneal viscera

Answer 16

• Mesogastrium mesentery → Lesser + greater omentum
  
  • Ab esophagus, stomach, duodenal cap, liver, biliary tract, gallbladder, spleen, tail of pancreas
• The mesentery
  
  • Jejunum, ileum, caecum + appendix
• T.mesocolon
  
  • T.colon
• Sigmoid mesocolon
  
  • Sigmoid colon
• Mesoappendix - holds appendix in place

Question 17

Mesogastrium

Answer 17

• G+L omentum
• Lesser omentum:
  
  • Stomach to INF surface of liver
  • Has thickening → provides passage for portal triad
  • L+R gastric vessels
• Greater omentum:
  
  • 4 layers (2 layers fold on itself)
    
    • Forms recess b/w layers
  • Encloses T.colon as well

Question 18

Role of the greater omentum

Answer 18

• Secrete serous fluid → allows movement of vis against others
• Secretes leukocytes
• Assists in localising infection by wrapping ~ inflammed structure
• Insulation for ab viscera

Question 19

Vessels of the greater omentum

Answer 19

• Take branches of the celiac trunk
• L+R gastro-omental vessels (anastomose along greater curvature)
• Short gastric vessels to the spleen

Question 20

Transverse mesocolon

Answer 20

• Starts from POS ab wall
• Lies on INF end of pancreas & covers most of duodenum
• Anteriorly covered by G.omentum

Question 21

Vessels of the transverse mesocolon

Answer 21

• Most vessels from SMA
• L colic flexure from IMA

Question 22

Root of mesentery

Answer 22

• Part of the mesentery that attaches to the body wall

Question 23

The mesentery

Answer 23

• Suspends SI, obliquely placed
• Distal duodenum → All of SI → ileocecal valve (including appendix)
• Overlie lumbar vert L3-5 → goes to R Psoas Maj

Question 24

Vessels of the mesentery

Answer 24

• SMVessels

Question 25

Mesoappendix & sigmoid mesocolon

Answer 25

• Mesoappendix
  
  • Covers appendix, has branch of SMA → the appendicular A
• Sigmoid mesocolon
  
  • Mobile, intraperitoneal part of LI
  • Branch of IMVessels → the SUP rectal vessels
  • Resides in pelvic cavity

Question 26

Peritoneal ligaments

Answer 26

• Connect fixed viscera to other viscera/or to ab wall
• May be part of a mesentery

Question 27

Peritoneal ligaments of the L omentum

Answer 27

• Hepato-gastric lig: main part of L.omentum connecting lesser curvature to liver
• Hepato-duodenal lig: thick lig enclosing portal triad → allows entry into omental bursa

Question 28

Peritoneal ligaments of the G omentum

Answer 28

• Gastrophrenic lig: stomach to diaphragm
• Gastro-lienal lig: Stomach to spleen
• Gastro-colic lig: Stomach to T.colon

Question 29

Falciform ligament

Answer 29

• Liver to ab wall

Question 30

What is the peritoneal cavity divided into

Answer 30

• Peritoneal cavity divided into G & L sacs

Question 31

Greater sac

Answer 31

• b/w parietal peritoneun & ANT aspect of viscera peritoneum
• To pelvic cavity
• b/w mesentery SI

Question 32

Lesser sac

Answer 32

• Blind pouch b/w liver & stomach, & b/w stomach & T.colon
• AKA omental bursa
  
  • Has epiploic foramen → pathway from G sac → L sac

Question 33

What makes up the blind pouch

Answer 33

• Splenorenal lig + gastrolienal lig → makes up the blind pouch