Andersons pediatric cardiology 1257
Bạn đang xem bản rút gọn của tài liệu. Xem và tải ngay bản đầy đủ của tài liệu tại đây (149.96 KB, 3 trang )
understoodonthebasisofthismodel.LAA,Leftaorticarch;LCCA,left
commoncarotidartery;LPA,leftpulmonaryartery;LSA,leftsubclavian
artery;MPA,mainpulmonaryartery;RAA,rightaorticarch;RCCA,right
commoncarotidartery;RPA,rightpulmonaryartery;RSA,rightsubclavian
artery.(ModifiedfromEdwardsJE.Anomaliesofthederivativesofthe
aorticarchsystem.MedClinNAm.1948;32:925–948;andEdwardsJE.
Vascularringsandslings.In:MollerJH,NealAN,eds.Fetal,Neonatal,and
InfantCardiacDisease.Norwalk:Appleton&Lange;1990:745–754.)
Withnormaldevelopment,theleftaorticarchandleft-sidedarterialduct
persist,whiletherightaorticarchdistaltotheoriginoftherightsubclavian
artery,alongwiththeright-sidedarterialduct,regress(Fig.47.2A).Asaresult,
theproximalpartoftheembryologicrightaorticarchremainsasthe
brachiocephalicartery,whichbifurcatesintotherightcommoncarotidandright
subclavianarteries.Thebrachiocephalicartery,ofcourse,isalsoknownasthe
innominateartery.Theleft-sidedaorticarch,insequence,givesrisetothe
brachiocephalic,leftcommoncarotid,andleftsubclavianarteries(Fig.47.2B–
C).Anomaliescanbepositionalorreflectabnormalbranchingduetopersistence
ofpartorpartsofthedoublearchthatnormallyshouldhaveregressed.In
exceptionalcases,nonetheless,itremainsdifficulttopredicttheembryologic
mechanism,evenusingtheconceptofthedoublearch.
FIG.47.2 (A)Stepsinvolvedinnormalformationofaleft-sidedaorticarch
withaleftarterialduct.Inthemodelofthehypotheticaldoublearch,as
shownatleft,theredbarsindicatethesegmentsthatregress.Inthe
normalleft-sidedaorticarch,shownatright,thisresultsindisappearance
oftherightaorticarch(RAA)distaltotheoriginoftherightsubclavian
artery(RSA),alongwithright-sidedarterialductregress.Inthefetal
circulation,asshowninthemiddlediagram,theaorticarch(redarrow)and
theleftarterialduct(bluearrow)makeaV-shapedconfluenceatthe
descendingaorta.Inthepostnatalcirculation,theleftarterialductcloses,
becomingthearterialligamentortheligamentousarterialduct.(B)The
fetalechocardiogramacrosstheuppermediastinumshowsthenormalleft
aorticarch(LAA)andleft-sidedarterialduct,formingaV-shaped
confluenceattheiruniontoformthedescendingaorta.(C)Thevolumerenderedmagneticresonanceangiogramseenfromthefront(left)andthe
computedtomographicangiogramseenfromabove(right)showthe
normalarrangementoftheleft-sidedaorticarch,whichgivesrise
sequentiallytothebrachiocephalic,leftcommoncarotidartery(LCCA),and
leftsubclavianartery(LSA).LV,Leftventricle;LPA,leftpulmonaryartery;
MPA,mainpulmonaryartery;RA,rightatrium;RV,rightventricle;RCCA,
rightcommoncarotidartery;RIA,rightinnominateartery;RPA,right
pulmonaryartery;SCV,superiorcavalvein.
