Download Thoracic Walls and Breast Thoracic wall • The main function of the

Lecture2–ThoracicWallsandBreast
Intercostal space
Rib/Thoracic cage
Thoracic wall (muscle, nerves and vessels)
Thoracicwall
• Themainfunctionofthethoracicwallistoprotecttheviscera Protects
Mechanical basis of
within
breathing
Includes thoracic cage and
• Mechanicalbasisofbreathing
covering
• Thoracicwallincludesthoraciccage(ribs,sternumand
Intercostal muscles
vertebra)andcovering(skinandmuscle)
Subcutaneous fat
Superficial fascia
Deep Fascia
Skin
Pectoralis Major
sweat glands, fat, blood
(superficial muscles)
and lymphatic vessels,
nerves, the mammary
Thoraciccage
gland.
Ribs
• Thereare12ribsandeachoftheseribsareassociatedwithacostalcartilage(anteriorly).Andthesecostal
cartilagesattachtheeachoftheribstothesternumanteriorly.
• Thecostalcartilageismovablesotheyareveryimportantformobilityofthethoraciccage(allowsitto
expandinbreathing)
• Theribscanbeclassifiedviavarioussystems
Costal cartilage
Rib
o True,false,floating
Ribs
Attaches
ribs
to
§ Ribs1-7=trueribs
sternum anteriorly
• Eachofthemattachdirectly
Contributes to
mobility of thoracic
Ribs 1-7 (True ribs)
tothesternumviathereown
cage
Attach directly to sternum via
costalcartilage
costal cartilage
§ Ribs8-10=falseribs
• Eachofthemattachtothe
Intercostal
costalcartilageoftherib
spaces
aboveit(nodirect
Ribs 11 and 12
(Floating ribs)
attachmenttothesternum)
Have no anterior
§ Ribs11-12=floatingribs
attachment
Ribs 8-10 (False ribs)
• Theyhavenoanterior
Attach to costal cartilage of
attachmentatall
rib above
o Typicaloratypical
Typical ribs (3-9)
Atypical ribs (1, 2, 10-12)
Curved and flat
§ Ribs3-9=typicalribs
Different markings
Superior facet
• Theyhaveallthesortsof
featuresthatmostoftheribs
Head
Inferior facet
Neck
Articular facet
have
Angle
Tubercle
Grooves for
• Curvedandflat
subclavian
vessels
• Therearesomelumps
particularlyintheposterior
Costal groove
Scalene tubercle
endthatarerelevantfor
Shaft
Superior view
articulationwiththevertebra
of rib 1
andforboththebodyofthe
Posterior view
Inferior view
vertebraandthetransverse
processes
• Thereisagroovearoundmostoftheshaftoftheribandthisiscalledthecostal
groove.Thisgroovesheltersandprotectstheintercostalvein,arteryandnervesin
theintercostalspace.
• Posteriorend
o thereare2articularprocessescalledfacets.Thereisaninferiorandsuperior
facet.Thesefacetsarticulatewiththebodyofthevertebra.
§ Superiorfacetarticulateswithinferiordemifacetofthebodyof
vertebraandtheinferiorfacetarticulateswiththesuperior
demifacetofthebodyofthevertebrabelow
o Thereisanarticularfacetandtuberclejustlateraltotheneck.
§ Thearticularfacetisusedforthearticulationwiththetransverse
processofthevertebra.So,theheadofeachribarticulateswiththe
Netter, F.H. Interactive Atlas of Human Anatomy. 3rd ed.
New Jersey, Icon Learning Systems, 2003, ISBN: 1-92900715-9, Plate #179
Author’s own
Author’s own
§
bodyofthevertebraandthetransverseprocessarticulateswiththe
transverseprocess
§ Thetubercleismadebymainlytheligamentsassociatedwiththe
jointsbetweentheribsandthevertebra
Ribs1-2,10-12=Atypicalribs
• Theylookdifferenttoatypicalribduetodifferentmarkings
• i.e.rib1(picture)–itisflatinthecoronalplaneunlikeotherribsthatareflat
vertically.Therearesomegroovesforthesubclavianvesselsoverthetopofthefirst
rib.Thereisascalenetubercleandthisisrelevantfortheattachmentofsomeofthe
scalenemusclesintheneck.
• [wedon’tneedtoknowthefeaturesofalltheatypicalribs–justknowthe
relationshipofthestructuresaroundtheseribsbasedonthelumpsetc.]
Sternum
Clavicular notch
Jugular notch
Sternum
• Thisiscommonlyknownasthebreastplate[check]andit
Manubrium
closestheanterioraspectofourribcage.
Sternal angle
Manubriosternal
(of Louis)
joint and
• Itismadeof3differentprocesses:
attachment of 2
Attachment for
o Manubrium
costal cartilage
costal cartilages
§ Ithasajugularnotchwhichhassomehighly
Body
innervatedperiosteumandskin
§ Clavicularnotch–forthearticulationofthe
Xiphoid
process
clavicles
§ Directlybelowtheclavicularnotchisthepointofarticulationforrib-1
• Rib2articulatesatthejunctionbetweenthemanubriumandthesternum=
manubriosternaljoint
o Inalateralview,wecanseeabumpthatisformedbytheangleofthe
manubriumandthesternumatthisjoint
o ThisisknownastheangleofLouisorthesternalangle
o Ifweweretoputahorizontallineallthewaythroughthethoraxwewillget
thistransverseplanethroughthesternalangleandthisiscalledtheplaneof
Louis
o Bodyofsternum
o Xiphoidprocess–thisislargelycartilaginousuntilmuchlaterislifewhenitstartstoossifyand
becomelesscartilaginous
Transverse
Superior
Thoracic
process
articular facet
Thoracicvertebra
vertebra
• Thoracicvertebrahasmanyfeaturessimilartoothervertebra
Body
buttheyhavesomeuniquefeatures
Spinous
process
Spinous process
Inferior articular
facet
Lamina
Transverse
Intervertebral
process
foramen
Intervertebral
Pedicle
disc
Articulationsforribs
Vertebral
Body
Thoracic vertebrae permit
canal
• Thereisasuperiordemifacetforthearticulationwiththerib Articulations
for ribsmainly rotation
ofthesamenumberasthevertebra
Costal facet
Superior demifacet
• Theinferiordemifacetarticulateswiththeribbelow
(head of its own rib)
Rib 3
• [note:Vertebraonehasasuperiorfacetnotademifacet
Inferior demifacet
andthefullribsitshere]
Costal
facet
• Costovertebraljoint–thejointwheretheribandthe
Costotransverse
vertebrajoins
joint
• Costotransversejoint–thejointbetweenthetransverse
Rib
processofthevertebraandtherib
Tubercle
o Therearesomeligamentsreinforcingthisandthis
Head
occursattheCostalfacetofthetransverseprocess
nd
Author’s own
Author’s own
Costovertebral joint
Author’s own
Intercostal space
Intercostalspace
Intercostal
Rib/Thoracic cage
(muscle, nerves and vessels)
• Intercostalspace–spacebetweeneachoftheribs
space
• Intercostalmuscles–musclesthatfillupthesespaces.
Intercostal muscles
Subcutaneous fat
Superficial fascia
Deep Fascia
Skin
Pectoralis Major
sweat glands, fat, blood
(superficial muscles)
and lymphatic vessels,
nerves, the mammary
gland.
Intercostalmuscles
• Thereare3layersofintercostalmuscles–theyallruninthe Intercostal
muscles
samesortoforientation
Internal
• Themostsuperficiallayerofthemusclesiscalledthe
intercostal
External
muscles
intercostal
externalintercostalmusclesandtheyrunantero-inferiorly
(posteromuscles
inferior)
o Theyprojectallthewaythroughthespace
(anteroDepress
inferior)
posteriorlyandanteriorlytheyformamembraneso
Elevate
therearenomusclefibresanteriorly
External
o Theexternalintercostalmuscleselevatetheribs
intercostal
o Theystopsomewhereatthecostochondraljunction membrane
• Thesecondlayerofmusclesiscalledtheinternalintercostal
musclesandtheyrunperpendiculartotheexternalintercostalmuscles–postero-inferiorly
o Posteriorly,thesemusclesbreakdownandformamembranebutanteriorlywecanseeallthe
musclesthroughtothesternum
o Thereare2typesofmovementsheredependingonwhereintheintercostalspace
§ Ifitislateraltothecostochondraljunction–becausetheyhavetheoppositefibredirection
toexternalintercostalmuscles,theinternalintercostalmuscleswilldepresstheribs(not
elevate)
§ Iftheyaremedialtothecostochondraljunction–
thentheywillelevatetheribs.Thisisduetothe
shapeoftheribs(3Dstructureoftheribs)
Innermost
• Innermostintercostalmuscles–theytendtobebrokendownand
intercostal
muscle
bepatchy
(posteroo Posteriorlytheyareverydeficient–thereisnomembrane
inferior)
either
Deficient
posteriorly
o Thedirectionofthesemusclefibresarethesameasthoseof
theinternalintercostalmusclessotheybothmusthavethe
samefunctions
Innermost intercostal muscle
Intercostal space
Intercostalspace
Internal intercostal muscle
• Intercostalveins,arteriesandnervesareinbetween
theinnermostintercostallayerandtheinternal
External intercostal muscle
Intercostal vein
intercostalmusclelayer.Theyareshelteredhighin
theintercostalspaceunderthecostalgroovepfthe Intercostal artery
ribabove.
Intercostal nerve
o So,ifwewanttotheaspiratesomefluidin
thepleurawewanttomakesurethatwe
penetrateabovetheribbelowtoavoid
goingclosetoanddamagingthis
neurovascularbundle
Costal groove of rib
Netter, F.H. Interactive Atlas of Human Anatomy. 3rd ed.
New Jersey, Icon Learning Systems, 2003, ISBN: 1-92900715-9, Plate #179
Eizenberg N, Briggs C, Barker P, Grkovic I. An@tomedia:
Thorax module. Melbourne An@tomedia Publishing, 2001,
ISBN: 0646 407 317
Eizenberg N, Briggs C, Barker P, Grkovic I. An@tomedia:
Thorax module. Melbourne An@tomedia Publishing,
2001, ISBN: 0646 407 317
Author’s own
Intercostal nerves
Intercostalnerves
• Thefigureisacoronalsection
• Intercostalnervesareextensionsofthespinal
segmentalnerveswhichcomesoutofthe
intervertebralforaminaofthevertebral
column
• Asthespinalnerveleavestheintervertebral
foraminaitalsogivesoffadorsalramusto
supplytheskinandmusclesoverthevertebral
column=erectorspinaemuscles
• Asitcomesoutlaterally,theseintercostal
nervesgiveoffmuscularbranchestoallthe
intercostalmuscles(inthesamesegment)and
thisisimportantastheyproducemovements
oftheribsthatcontributetobreathing
Rami
Intercostal
• Asitgoesthroughandrunsforward,itendsup
communicantes
nerve
Innermost
terminatingatsomecutaneousbranchesontheanterior
intercostal
Sympathetic
muscle
ganglion
thoracicwallandalsosomelateralcutaneousbranches
deficient
posteriorly
whichinnervatestheskinoverthelateralthoracicwall.
o Eachofthesebranchessupplyastripofskinover
thethoracicwallwhichisrelatedtothatspinal
T4 teets
segmentalwall.Thismakesiteasyforustodefine
T1O
thedermatomesinrelativetotheintercostal
spaces.(itisasinglenervehere–thereareno
plexusesandthereisnomixingetc.)
Sympathetic trunk
• Thereare12thoracicsegments.T4=stripovernipples
andT10=stripoverbellybutton
Intercostal
Intercostalvessels
vessels
• Thereare2intercostalarteries–1posterior
whichentersthespacefrombehindand1
anterioronethatentersthespacefromthe
front.
• Posteriorintercostalarteriesarejustsegmental
branchesofthethoracicaorta
• Anteriorintercostalarteriesarebranchesofthe
internalthoracicarteries.Theinternalthoracic
arteriesarebranchesofthesubclavianartery
andtheydescendposteriorandlateraltothe
sternumallthewaydownthesegmentsgiving
anteriorintercostalarteriesintotheanterior
aspectoftheintercostalspace.
• Anteriorandposteriorintercostalnervesanastomosewitheachothersomewhereontheanteriorthoracic
wall.Thisisimportantclinicallyasitprovidesanalternate
Posterior intercostal
Descending aorta
artery
routeforbloodtosomeoftheskinandmuscleinthis
intercostalspace
o Theinternalintercostalarteriesareoftenusedfor
Internal
thoracic
bypassesofcoronaryarteryblockages.
vessels
• Thetransversusthoracismuscleisontheinsideoftheanterior
thoracicwall.Itattachespartlytothesternumsoithasitsown
name.Butithasthesamesortoffunctionsastheinnermost
Anterior
intercostalmuscles.
intercostal artery
Internal thoracic
Transversus
artery
thoracis
Moore K L. Clinically Oriented Anatomy. 2nd ed. Williams and
Wilkins; 1985. ISBN 0683061321. Ch.1 Page 65
Netter, F.H.
Interactive Atlas of
Human Anatomy. 3rd
ed. New Jersey, Icon
Learning Systems,
2003, ISBN: 1929007-15-9, Plate
#150
Netter, F.H. Interactive Atlas of Human Anatomy. 3rd ed.
New Jersey, Icon Learning Systems, 2003, ISBN: 1-92900715-9, Plate #179
Moore K L. Clinically Oriented Anatomy. 2nd ed. Williams and
Wilkins; 1985. ISBN 0683061321. Ch.1 Page 65
Netter, F.H. Interactive Atlas of Human Anatomy. 3rd ed. New
Jersey, Icon Learning Systems, 2003, ISBN: 1-929007-15-9,
Plate #176
Netter, F.H. Interactive Atlas of Human Anatomy. 3rd ed.
New Jersey, Icon Learning Systems, 2003, ISBN: 1-92900715-9, Plate #179