Andersons pediatric cardiology 76
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FIG.2.22 Aorticrootopenedbetweentheleftcoronaryandnonadjacent
sinusesandphotographedfrombehind.Itshowsthesemilunarhingesof
theleaflets,withtheleafletsguardingthecoronaryaorticsinusescrossing
theanatomicventriculoarterialjunctiontoincorporatemyocardiumintothe
basesofthesesinuses.
Posteriorly,twooftheleafletsoftheaorticvalveareinfibrouscontinuitywith
thedeepaorticleafletofthemitralvalve.Unlikethepulmonaryvalve,where
eachsinusincorporatesamyocardialbase(seeFig.2.17),thesemilunar
attachmentsoftheleafletsoftheaorticvalveincorporatecrescentsof
myocardiumonlywithinthebasesofthetwosinuses,whichgiverisetothe
coronaryarteries.Inkeepingwiththepulmonaryroot,nonetheless,three
trianglesofarterialwallareincorporatedwithintheoutflowtractbeneaththe
apicesofthezonesofappositionbetweenthevalvarleaflets.Thelocationof
thesethreefibroustriangleshelpsinunderstandingtherelationshipsoftheaortic
valve.12Theleafletsofthevalveitselfarenamedaccordingtotheoriginofthe
coronaryarteriesfromtheaorticsinuses.Thus,thesinuses,andtheleafletsthey
support,canbedistinguishedasbeingleftcoronary,rightcoronary,and
nonadjacent.Weprefer“nonadjacent”to“noncoronary”because,veryrarely,the
nonadjacentsinuscangiveorigintoacoronaryartery.Insuchasetting,the
noncoronarytitlewouldbecomenonsensical.“Nonadjacent”isalsoagoodterm
because,withoutexception,andirrespectiveoftherelationshipsofthearterial
trunks,twooftheaorticsinusesareadjacenttocorrespondingsinusesofthe
pulmonarytrunk.Thispermitsthesinusesofthepulmonarytrunksimilarlytobe
distinguishedasrightfacing,leftfacing,andnonadjacent.Thefibroustriangle
thatseparatestheleftcoronaryleafletfromthenonadjacentleafletoftheaortic
valveseparatestheleftventricularoutflowtractfromthetransversesinusofthe
pericardium,formingthewallbetweenthebackoftheaortaandtheanterior
interatrialgroove(seeFig.2.2,left).Thetriangleseparatingtherightcoronary
aorticleafletfromthenonadjacentleafletisdirectlycontinuouswiththe
membranousseptum.Itseparatestheleftventricularoutflowtractfromthe
transversesinusabovetheinnercurvatureoftherightventricle,specificallywith
thepericardialspaceabovethesupraventricularcrest(Fig.2.23).
FIG.2.23 Multidetector-rowcomputedtomographicdatasetreconstructed
toshowtherelationshipsoftheinterleaflettrianglebetweenthe
nonadjacentandrightcoronaryaorticvalvarsinuses.
Thetrianglethatseparatesthetwocoronaryleafletsoftheaorticvalve
separatesthecavityoftheleftventriclefromthefibro-adiposetissueinterposing
betweentheanteriorsurfaceoftheaortaandtheposteriorsurfaceofthefreestandingsubpulmonaryinfundibulum.
ArterialTrunks
Thetwogreatarteriesleavethebaseoftheheartattheventriculoarterial
junctions,extendingsuperiorlyintothemediastinum,withthepulmonarytrunk
spiralingaroundthecentrallylocatedaortaasitbifurcates.Itsbranchesthen
extendtothehilumsofthelungs.Eacharterialtrunkshowsacharacteristic
clovershapeatitsroot,wherethetruncalsinusesinterdigitatewiththe
supportingventricularstructuresastheysupportthearterialvalvarleafletsin
semilunarfashion.Thewell-formedsinutubularjunctionseparatestheexpanded
sinusesandthetubulartrunkofeachgreatartery.Thetipsofthezonesof
appositionbetweenthearterialvalvarleaflets,usuallyknownasthe
commissures,arefirmlyattachedtothissinutubularjunction,thusmakingitan
integralpartofthevalvarcomplex(Fig.2.24).
FIG.2.24 Aortictrunkbisectedatthelevelofthesinutubularjunction,with
therootphotographedfromthearterialaspect.Theperipheralendsofthe
zonesofappositionbetweentheleaflets(whitestars)areattachedatthe
levelofthesinutubularjunction.Theleafletscometogetheratthecentroid
ofthevalvarorifice(redstar).
Stenosisoccurringatthislevel,therefore,isvalvarratherthansupravalvar.
Thearrangementoftheclosedvalvealsoshowsthattheentiretyofthezonesof
appositionbetweentheleafletsshouldbeconsideredtorepresentthe
