imaginganatomyofperitoneum-170126182046.pdf

Peritoneum

1. Nagaraju.B

2. Theperitoneumisathin,translucent,serous
membraneandisthelargestandmostcomplexly
arrangedserousmembraneinthebody
Theperitoneumthatlinestheabdominalwallis
calledtheparietalperitoneum
whereastheperitoneumthatcoversaviscusor
anorganiscalledavisceralperitoneum

3. Bothtypesofperitoneumconsistofasinglelayer
ofsimplelow-cuboidalepitheliumcalleda
mesothelium
Acapillaryfilmofserousfluid(approximately
50–100mL)separatestheparietalandvisceral
layersofperitoneumfromoneanotherand
lubricatestheperitonealsurfaces

4. Theperitonealcavityisapotentialspacebetween
theparietalperitoneum,whichlinesthe
abdominalwall,andthevisceralperitoneum,
whichenvelopestheabdominalorgans
Inmen,theperitonealcavityisclosed,butin
women,itcommunicateswiththeextraperitoneal
pelvisexteriorlythroughthefallopiantubes

5. Theperitonealspacesarepotentialspacesthat
arenotnormallyvisualizedunlesstheyare
distendedwithfluidorthefasciaisthick
Foldsofperitoneum,calledligaments,connect
andprovidesupportforstructureswithinthis
cavity
Knowledgeoftheanatomicspacesiscriticalfor
thediagnosis,staging,andtreatmentoffluid
collectionsbyeithersurgicalorradiologic
methods

6. Variousimagingmodalities
Plainradiographyhasbeensupersededby
crosssectionalimagingtechniquesandthe
peritonealcavityisvisualizedonlyviacontrast
herniography.
US
Ultrasoundiswidelyusedtodetect
intraperitonealcollections,butislimitedbybowel
gasandbodyhabitus.

9. CT/MRI
Contrast-enhancedCT(withorwithoutoral
contrastmedium)isthemethodofchoiceto
evaluatetheperitonealspaces,reflectionsand
theircontents.
MRIprovidesgoodvisualizationofthe
peritonealspacesandreflections;however,bowel
peristalsisandrespiratorymovementcandegrade
theimages.

10. Peritonealspaces
Thetwomainperitonealcompartmentsare
separatedbythetransversemesocolon.
Supramesocoliccompartment
Dividedarbitrarilyintorightandleft
supramesocolicperitonealspaces,whichcanbe
furthersubdividedintoanumberofsubspaces
thatareincommunication.

11. •Rightsupramesocolicspace
Threesubspaces
•Rightsubphrenicspace
extendsoverthediaphragmaticsurfaceofthe
rightlobeofthelivertotherightcoronary
ligament
posteroinferiorlyandthefalciformligament
medially(whichseparatesitfromtheleft
subphrenicspace)
•Rightsubhepaticspace
Anteriorrightsubhepaticspaceislimitedinferiorly
bythetransversecolonanditsmesentery

12. •Posteriorrightsubhepaticspace(hepatorenal
fossaorMorison’spouch)
Extendsposteriorlytotheperitoneum
overlyingtherightkidney
Boundedsuperiorlybytheinferiorsurfaceof
therightlobeoftheliver
Communicates freelywiththeright
subphrenicspaceandtherightparacolicgutter

13. Coronalimage ofthe
anteriorabdomen ina
patientwithdilutecontrast
materialinjectedintothe
Peritoneum
Therightsubphrenicspace
(RSP)extendsfromthe
falciformligament (F)
laterallybetween the
abdominalwallandtheliver
This space then
communicateswiththeright
pericolicspace(RC)andthe
rightsubhepaticspace(RS).
Theleftsubphrenicspace
(LSP)communicateswiththe
leftsubhepaticspace(lsh).

16. Lessersac
•Posteriortothelesseromentum,stomach,
duodenalbulbandgastrocolicligament;anterior
tothepancreas
•Communicateswiththerestoftheperitoneal
cavitythroughtheepiploicforamen(ofWinslow),
whichliesbetweentheinferiorvenacavaandthe
freemarginofthehepatoduodenalligament
•Lessersacdividedintotworecessesbythe
pancreatogastricfold(peritonealfoldoverthe
leftgastricartery):

17. Smallersuperiorrecesscompletelyenclosesthe
caudatelobeoftheliverandliesposteriortothe
portalveinattheportahepatis.superiorly,it
extendsdeepintothefissurefortheligamentum
venosumandposteriorlyliesadjacenttothe
rightdiaphragmaticcrus.
Largerinferiorrecessliesbetweenthestomach
andthepancreas;itisboundedinferiorlybythe
transversecolonanditsmesentery,butcanextend
foravariabledistancewithinthe
greateromentum;totheleftitisboundedbythe
gastrosplenicandsplenorenalligaments

18. Theanatomicboundaries
ofthelessersacare
noted.Thesac(L)is
anteriortothepancreas
(P) and extends
posteriorlybehindthe
stomach(ST)asthe
splenicrecess(SR)
Themarginofthe
foramenofWinslow(w)
containstheportalvein,
thehepaticartery,and
thecommonbileduct

19. This level
demonstratesthe
attachmentofthe
coronaryligaments
oftherightlobeof
theliver(straight
arrows)
Therecessesof
thelessersac,the
superiorrecess(S)
adjacenttothe
venacava(v),and
thesplenicrecess
(SP)behindthe
stomachareseen.

20. Leftsupramesocolicspace;
•Fourarbitrarysubspaces,whicharein
communication witheachotherinnormal
individuals:
Anteriorleftperihepaticspace
•Boundedmediallybythefalciformligament,
posteriorlybytheliversurfaceandleftcoronary
ligament,andanteriorlybythediaphragm
•Communicatessuperiorlyandtotheleftwiththe
leftanteriorsubphrenicspace,andinferiorlywith
thegreaterperitonealcavityoverthesurfaceof
thetransversemesocolon

21. Posterior left perihepaticspace(gastrohepatic
recess):
•Surroundsthelateralsegmentoftheleft
hepaticlobeextendingintothefissureforthe
ligamentumvenosumontherightanteriortothe
mainportalvein
•Posteriorly,thelesseromentumseparatesthis
spacefromthesuperiorrecessofthelessersac.
Boundedontheleftbythelessercurvatureofthe
stomach
•Communicatesanteroinferiorlywiththeanterior
leftperihepaticspace

22. Anterior left subphrenicspace
•Thisliesbetweenthestomachandtheleft
hemidiaphragm
•Communicatesontherightwiththeleftanterior
perihepaticspace,andposteriorlywiththe
posteriorsubphrenic(perisplenic)space
Posterior left subphrenic(perisplenic) space
•Superiortogastricfundusandspleen
•Coversthesuperiorandinferolateralsurfaces
ofthespleen

23. •Limitedinferiorlybythesplenorenaland
phrenicocolicligaments,andmoresuperiorlyby
thegastrosplenicligament
•Partiallyseparatedfromtherestoftheperitoneal
cavitybythephrenicocolicligamentwhich
extendsfromthesplenicflexuretothe
diaphragm

24. Sagittalimageclose
tomidline.
Theliver(LL)and
adjacentstructures
areseen,including
theanteriorleft
subphrenic space
(alsp),thesuperior
recessofthelesser
sac(smallangled
arrow),andthe“bare
area”oftheliver
(horizontalarrow).

25. Inframesocoliccompartment
•Dividedintotwounequalspacesposteriorlybythe
rootofthesmallbowelmesentery
Rightinframesocolicspace
•Boundedbythetransversemesocolonsuperiorly
andtoright,andbytherootofthesmallbowel
mesenteryinferiorlyandtoleft
Leftinframesocolicspace
•Infreecommunicationwiththepelvistotheright
ofthemidline
•Sigmoidmesocolonformsapartialbarriertothe
leftofthemidline

26. Paracolicgutters
•Peritonealrecessesontheposteriorabdominal
walllateraltotheascendinganddescending
colon
•Rightparacolicgutter:continuoussuperiorlywith
therightsubhepaticandsubphrenicspaces;
largerthantheleft
•Leftparacolicgutter:partiallyseparatedfromthe
leftsubphrenicspacesbythephrenicocolic
ligament.
•Bothparacolicspacesareincontinuitywiththe
pelvicperitonealspaces.

28. Pelvicperitonealspaces
•Inferiorlytheperitoneumisreflectedoverthe
domeofthebladder,theanteriorandposterior
surfaceoftheuterusandupperposteriorvagina
infemales,andontothefrontoftherectumat
thejunctionofitsmiddleandlowerthirds
•Theurinarybladdersubdividesthepelvisinto
rightandleftparavesicalspaces

29. Inmen,thereisonlyonepotentialspaceforfluid
collectionposteriortothebladder,the
rectovesicalpouch.
Inwomen therearetwopotentialspaces:
posteriortothebladder,theuterovesicalpouch
and,posteriortotheuterus,thedeeper
rectouterinepouch(ofDouglas).
Thelayersofperitoneumontheanteriorand
posteriorsurfacesoftheuterusarereflected
laterallytothepelvicsidewallsasthebroad
ligaments,containingthefallopiantubes.

33. Terminology

34. 1.Rightcoronaryligament
•Formedbythereflectionoftheperitoneumfrom
thediaphragmtotheposteriorsurfaceoftheright
lobeoftheliver
•Thetriangularareaofliverenclosedbytheselayers
isthebareareadevoidofperitonealcoveringand
iscontinuouswiththeanteriorpararenalspace
2.Leftcoronaryligament(lefttriangularligament):
•Fimsystructureformedbyappositionofthe
peritonealreflectionsbetweentheleftlobeof
liveranddiaphragm
•Littleclinicalsignifcance

35. 3.Gastrosplenicligament
•Extendsfromthegreatercurveofthestomachto
thespleen
•Continuouswiththegreateromentum
•Containstheleftgastroepiploicandshortgastric
vessels
4.Falciformligament
•Extendsfromtheanterosuperiorsurfaceofthe
livertothediaphragmandanteriorabdominal
wall,carryingtheligamentumteres(obliterated
leftumbilicalvein)initsfreeedge,incontinuity
withthefissurefortheligamentumvenosumand
coronaryligaments

37. 5.Phrenicocolicligament
•Extendsfromthesplenicflexuretothe
diaphragmattheleveloftheeleventhrib
•Continuouswiththetransversemesocolonand
splenorenalligament
•Supportsthespleen
•Potentialbarriertothespreadofinfectedfluid
fromthepelvisandleftparacolicguttertothe
leftsubphrenicspace

38. 6.Splenorenalligament
•Extendsfromthetipofthepancreatictailtothe
splenichilum,carryingthesplenicvessels
•Continuouswiththegastrosplenicligament,
formingtheleflateralboundaryofthelessersac

39. 7.Hepatoduodenalligament
•Representsthethickenedfreerightedgeofthe
lesseromentum(gastrohepaticligament)
•Extendsfromtheflexurebetweenthefirstand
secondpartsoftheduodenum totheporta
hepatis
•Carriestheportaltriad(hepaticartery,portalvein
andcommonbileduct)&anteriormarginofthe
epiploicforamen(ofWinslow)

40. 8.Duodenocolicligament
•Extendsfromthehepaticflexuretothe
descendingduodenum
•Continuouswiththetransversemesocolon
•Carriesthelymphaticdrainageoftheright-sided
colontothecentralsuperiormesentericnodes

42. 1. Greater omentum( gastrocolicligament)
•Largestperitonealfoldconsistingofadouble
sheetfoldedonitself(i.e.madeupoffourlayers)
•Twolayersofperitoneumdescendfromthe
greatercurveofthestomachandproximal
duodenum passinginferiorly,anteriortothe
smallbowelforavariabledistance,andthenturn
superiorlyagaintoinsertintotheanterosuperior
aspectofthetransversecolon

43. •Theleftborderiscontinuouswiththe
gastrosplenicligament
•Therightborderextendstotheoriginofthe
duodenum
•Containsadiposetissuewhichiseasilyidentifed
onCTanteriortothetransversecolonsuperiorly
andloopsofsmallbowelinferiorly

45. 2.Lesseromentum(gastrohepaticligament)
•Extendsfromthelessercurvatureofthestomach
andproximal2cmoftheduodenumtotheliver
(attachedtothefissuresfortheportahepatisand
ligamentumvenosum)
•Formstheanteriorsurfaceofthelessersac
•Thefreeedgeformsthehepatoduodenal
ligament

46. •Generallywedge-shapedandcontainsadipose
tissue,thegastricartery,thecoronaryvein,and
theleftgastricnodalchain
•Identifedoncross-sectionalimagingbyfinding
thefissurefortheligamentum venosum
immediatelyinferiortothegastro-oesophageal
junction

48. 1. Small bowel mesentery
•Containsfat,thejejunalandilealbranchesofthe
superiormesenteric arteriesand their
accompanyingveins,nervesandlymphatics
•Suspends20–25feetofjejunumandileum
•Connectedtotheposteriorabdominalwallbyan
oblique15cmrootextendingfromthe
duodenojejunalflexuretotheileocaecalvalve

49. •Therootisabareareacontinuouswiththeleft
anteriorpararenalspacesuperiorlyandtheright
anteriorpararenalspaceinferiorly;itpassesin
frontofthehorizontalpartoftheduodenum
(wherethesuperiormesentericvesselsenterthe
mesentery),abdominalaorta,inferiorvenacava,
rightureterandrightpsoasmuscleasittravels
fromlefttoright

51. 2. Transverse mesocolon
•Connectsthetransversecolontotheposterior
abdominalwall
•Formedbytwolayerspassingfromtheanterior
surfaceoftheheadandtheanteriorborderof
thebodyofthepancreastotheposteriorsurface
ofthetransversecolon,wheretheyseparateto
surroundthebowel
•Theupperlayerisadherentto,butseparable
from,thegreateromentum

52. •Carriesthemiddlecolicvessels,autonomic
nerves,andlymphaticswhichsupplythe
transversecolon
•Becomesconfluentwiththerootofthesmall
bowelmesenteryneartheuncinateprocessof
thepancreas

54. 3.Sigmoidmesocolon
•Attachesthesigmoidcolontothepelvicwallin
aninvertedV,theapexofwhichliesanteriorto
theleftcommoniliacarterybifurcationandleft
ureter;theleftlimbdescendsmediallytotheleft
psoasmuscle;therightlimbdescendsintothe
pelvisandendsinthemidlineanteriortoS3
•Carriesthesigmoidandsuperiorrectalvessels

55. 4.Mesoappendix
•Surroundsthevermiformappendixandattaches
tothelowerendofthesmallbowelmesentery
closetotheileocaecaljunction
•Usuallyextendstothetipoftheappendixand
sometimessuspendsthecaecum

57. In the normal abdomen without intraperitoneal
disease, there is a small amount of peritoneal fluid
that continuously circulates.
The movement of fluid in this circulatory pathway
is produced by the movement of the diaphragm
and peristalsis of bowel.
It predominantly flows up the right paracolicgutter
which is deeper and wider than the left and is
partially cleared by the subphreniclymphatics.

58. There are watershed regions in the peritoneal
cavity that are areas of fluid stasis:
Ileocolic region
Root of the sigmoid mesentery
Pouch of Douglas
When you are staging a patient for
gastrointestinal malignancy you have to look for
disease in these areas of stasis.
90% of peritoneal fluid is cleared at the subphrenic
space by the submesotheliallymphatics.
These lymphatics are connected with lymphatics at
the other side of the diaphragm.

59. The peritoneum is continuous in the male pelvis.
In women the peritoneum is discontinuous at the
ostia of the oviducts.
Through this opening disease can spread from
the extraperitonealpelvis into the peritoneal
cavity.
For example, pelvic inflammatory disease (PID).