Gastrointestinal tract introduction lecture

1st lecture

1. ANATOMY OF THE G.I.T.
DR. MAHMOUD MISHAAL
THE ANTERIOR
ABDOMINAL WALL

2. 1-Todescribethedivisionofabdomeninto
regions.
2-Todefinethemainsurfacelandmarks.
3-Toexplorethelayersoftheanteriorabdominal
wall.

3. Thediaphragmclosestheabdomen
superiorlyfromthethorax.
Abdominalcavitybulgesinsidethe
domeofthediaphragm,soinahorizontal
sectionatsubdiaphragmaticlevelyou
canseetheabdomeninthecentwer&
thoraxintheperiphery

4. Functions:
1-Houses major viscera
2-Respiration
3-Controlsabdominal
pressureincertain
physiologicalactivities

5. Planesofdivision:
Horizontalplanes:
Subcostal:L3(tipsof10
th
costal
cartilages)
Intertubercular:L5
Verticalplanes:
Leftlateral(MCL)
Rightlateral(MCL)
Thetranspyloricplane:
-Passesthroughthetipsof9
th
costal
cartilages(L1vertebra)
-Cutsthroughthepylorus,pancreas,
renalhilum,gallbladder&Tmesocolon
TPP

6. Thenineregions:
-Rt&Lthypochondria
-Epigastricregion
-Rt&Ltlumbarregions
-Umbilicalregion
-Rt&Ltiliacfossae
-Hypogastric(suprapubic)region

7. Surfacelandmarks:
1.Costalmargin
2.Infrasternalangle
3.Iliaccrest
4.Iliactubercle(L5)
5.Ant.superioriliacspine
(S1)
6.Pubiccrest:Theupper
borderofthepubicbone
7.Pubic tubercle:The
projectingmostlateral
endofthepubiccrest
8.Inguinalligament
1
2
3
5
8

8. 9-Lineaalba:Strongfibrous
band,extendsfromthe
symphysis pubistothe
xiphisternum
10-Lineasemilunaris:The
curvedlateralborderofthe
rectussheath
11-Lineatransverse:Thesurface
markingsofthetendinous
intersectionsoftherectus
muscle,3oneachside
(xiphisternal,umbilical&one
inbetween)
12-UmbilicusL3-L4(notfixed)
9
10
11
12

9. Dermatomes

11. TheFIVElayers:
1-Skin.
2-Superficial fascia :
Superficial fatty layer
Deep membranous layer
3-Muscular layer :
External oblique
Internal oblique
Transversus abdominis
Rectus abdominis
Pyramidalis
4-fascia transversalis.
5-Extraperitoneal connective tissue.

12. Langer
Lines

13. Superficialfascia:
Abovetheumbilicus:Singlefattylayer
Belowtheumbilicus:Splitsinto:
1-Superficialfattylayer(Camper’s
fascia):
Continuesdownward:
-Male;withthesuperficialfasciaofthe
penis&dartosmuscle
-Female;withsuperficialfasciaof
labiummajus.

14. 2-Deepmembranouslayer(Scarpa’s
fascia):
Extendsintotheupperthigh&
fuseswiththefascialata(1cm
belowtheinguinalligament)
Liesjusttoexternaloblique
Spacedeeptoitcommunicates
perineal&scrotalsubcutaneous
spaces

15. Muscle Origin Insertion Inervation Function
External
oblique
Outersurfacesofthe
lowereightribs
Laterallipof
iliaccrest
Lineaalba
T7 -T12
Compressabdominalcontents
Flextrunk(bilateral)
Bendstrunktosameside
(unilateral)
Turnsanteriorpartofabdomen
tooppositeside(unilateral)
Internal
oblique
Thoracolumbarfascia
Iliaccrest
Lateral2/3ofinguinal
ligament
Lower3-4ribs
Lineaalba
Pubiccrest
Pectinealline
(conjointtendon)
T7 -L1
Compressabdominalcontents
Flextrunk(bilateral)
Bendstrunktosameside
(unilateral)
Turnsanteriorpartofabdomen
tosameside(unilateral)
Transversus
abdominis
Thoracolumbarfascia
Mediallipofiliaccrest
Lateral1/3ofinguinal
ligament
Lower six costal
cartilages
Lineaalba
Pubiccrest
Pectinealline
(conjointtendon)
T7 -L1Compressabdominalcontents
Rectus
abdominis
Pubiccrest&tubercle
5-7 costal
cartilages
xiphoidprocess
T7 -T12
Compressabdominalcontents
Flexvertebralcolumn
PyramidalisFrontofpubis Lineaalba T12 Tensesthelineaalba
Themuscularlayer:

16. Externalabdominaloblique:
-Musculo-aponeuroticflatsheet
-Fibersaredirectedanteromedially
&downward
Borders:
Medial;fusesatlineaalba
Superior;overthechestwall
Inferior;theinguinalligament
Posterior;formsthelumbar
triangle(withL.dorsi&iliaccrest)
Free

18. Structuresrelatedtoexternaloblique:
1-Inguinalligament:
Itisthelowerrolled-underfreeedge
extendingbetweentheASIS&pubic
tubercle
2-Lacunarligament:
•Flattriangularligamentfillstheangle
betweenthemedialendoftheinguinal
lig.&thepectenpubis
•Itformsthemedialboundaryofthe
femoralcanal

19. 3-Reflectedinguinalligament:
Minorfibersascendfromthepubic
tubercleupward&mediallytoendin
lineaalbajustabovethesymphysis
4-Superficialinguinalring:
•AtriangularopeninginEOaponeurosis
above&lateraltothepubictubercle
•Fromitsbordersextendstheexternal
spermaticfascialikethearmoftheshirt
•Hasmedial&lateralcrura
•Ittransmitsthespermaticcordinmale&
theroundligamentofuterusinfemale
5-Intercruralfibers:
-LieatthesuperolateralangleoftheSIR
6-Externalspermaticfascia
4
5
3

20. Internaloblique:
Representsthemiddlelayer
ofthebodywallmusculature
Fibersaredirectedupward&
medially

21. Transversusabdominis:
Thisistheinnermostlayerofthe
bodywall
Fibersaretransverse

22. StructuresrelatedtoIO&TA:
1-Conjointtendon:
-ThefusedlowerfibersofIO&TA
thatoriginatefromtheinguinal
ligament
-ArchesfromthelateralpartofILin
aposteromedialdirectiontothe
pectenpubis
-Formsthemedialpartofposterior
walloftheinguinalcanal
-SuppliedbyilioinguinalnerveL1
-Itsparalysispredisposetodirect
inguinalhernia

23. 2-Cremastericmuscle:
-Tube likemuscular sheath
prolongedfromIO&TA(mainlyIO)
-Formsthemiddlelayerofthe
spermaticcord
-Suppliedbygenitalbranchof
genitofemoralnerve(L2)
-Movesthetestisreflexlyup&
downtoregulateitstemperature

24. Rectusabdominis:
-Theseverticalmuscleslieon
eachsideoflineaalba
-Itshowsthreetendinous
intersections,thelowestlieat
theleveloftheumbilicus,the
highestatthexiphoidprocess
&themiddleinbetween
-Theseareshownonthe
abdominalsurfaceaslinea
transversae

26. Therectussheath:
-AponeuroticsheathinsidewhichtheRAlie
loosely
-AstheaponeurosisofIOapproacheslinea
semilunarisitsplitsinto2laminae,anterior&
posteriortoRA
-EOpassesanteriortotheanteriorlamina&TA
passesbehindtheposteriorlamina
-2cmbelowtheumbilicus,RAperforatesthe
posteriorlamina
-ThusallthethreelaminaepassinfrontofRA
whichwilllieonfasciatransversalis
-Thelowerfreeborderoftheposteriorwallof
thesheathissharp&namedthearcuateline
(foldofDouglas)

27. Rectus sheath is essential in supporting the AAW to
stand the weight of abdominal contents
Incisions attacking rectus sheath are more prone to
incisional hernias

28. Functions of abdominal muscles:
1-Support & protection of abdominal viscera.
2-Raises intra-abdominal pressure.
3-Respiration.
4-Movements of trunk:
-RA; flexion
-TA + obliques; lateral flexion + rotation

29. Theneurovascularplane:
•Thisplanewherethevessels&nervesoftheAAWpass,itlies
betweentheIO&TA
•TheAAWissuppliedbythelower6thoracic&L1nerves
•L1nerve(iliohypogastricn.)withitscollateralbranch(ilioinguinaln.)
hasspecialimportanceintheircourse

30. •Iliohypogastricn.piercesIO
abovetheanteriorsuperioriliac
spine&piercesEOabovethe
superficialinguinalring
•Ilioinguinaln.piercesIOabove
thelateralendoftheinguinal
ligament&leavesthroughthe
superficialinguinalring

31. Fasciatransversalis:
•Thisafirmmembranewhichforms
the4
th
layeroftheAAW
•OntheposteriorAWitisfusedwith
thelumbarfasciathatcoversmuscles
ofPAW
•Itextendsabovetoformtheinferior
diaphragmaticfascia&belowon
fasciailiaca&pelvicfascia
•Itformstheposteriorwallofrectus
sheathbelowthearcuateline&
posteriorwallofinguinalcanallateral
totheconjointtendon

32. Derivativesoffasciatransversalis:
1-Theanteriorwalloffemoralsheath
2-Theinternalspermaticfascia:theinnermostcoveringofthecord
1
2

33. Theextraperitonealconnectivetissue:
•Thisisafibroelastictissueseparating
theabdominalwallfromtheparietal
peritoneumoftheAAW
•Itisfilledwithfatinobeseindividuals
butinslimindividualsitisfibrous