大脑前动脉系

ANTERIORCEREBRALARTERY泰和医院神经外科何承彪Anteriorcerebralarterial

systemTheanteriorcerebralarterialsystemincludestheanteriorcerebralartery,theanteriorcommunicatingartey,pericallosalarteryanditsbranches.Itsuppliesthemedialaspectofthefrontalandparietallobes,thecaudatenucleus,basalganglion,corpuscallosumandthebaseofthefrontallobe.AnteriorcerebralarterialsystemThemedialaspectofthecerebralhemisphereisdividedinto8areaswhicharesuppliedbybranchesoftheanteriorcerebralarterybearingthesamenames.Onlythehorizontalsegmentofthearteryiscalledtheanteriorcerebral.AnteriorcerebralarterialsystemTheanteriorcerebralarteryisdividedinto5segmentsA1segment:theproximalorhorizontalsegment,fromthebifurcationoftheinternalcarotidarterytotheanteriorcommunicatingartery;A2segment:thesegmentinferiortothecorpuscallosumwhichconvexanteriorly;A3segment:thesegmentalongthegenuofcorpuscallosumwhichconvexanteriorly;A4segment:thesegmentalongthesuperiormarginofthecorpuscallosumatthefrontallobe;A5segment:theterminalsegment,whichrunsalongthemarginofthecorpuscallosumattheparietallobe.1、A1SEGMENTItcurvesslightlysuperiorlyorrunshorizontallyinA-PorWater’sview.TherecurrentarteryofHeubneristhelargestperforatingbranchofA1segmentwithadiameterof0.2-2.9mm(average1mm),whichrunslaterallyfor2-3cmandthenenterstheanteriorperforatingsubstancetosupplytheanteriorpartofthecaudatenucleus,theanterior1/3oftheputamen,anteriortipoftheglobuspallidusexternusandtheanteriorlimboftheinternalcapsule.2.ANTERIORCOMMUNICATINGARTERYItsituatesbetweenbilateralanteriorcerebralarteries,about1-2mminlength,andformstheanteriorpartofcircleofWillis.Itgivesmanyperforatingbranchestosupplytheinfundibulum,opticchiasm,anterioraspectofhippocampus,rostralpartofthecorpuscallosum,theadjacentcortex,septumpellucidumandthecolumnsofthefornix.ANTERIOR

COMMUNICATINGARTERYTheanteriorcerebralarteriesareconnectedtogetherviatheanteriorcommunicatingarterywithintheinterhemisphericfissure.Ifthereisabsentofanteriorcerebralarteryononeside,thecontralateralanteriorcerebralarterywillsupplythatsidethroughtheanteriorcommunicatingartery,whichmayleadtotheformationofaneurysmduetohaemodynamicreason.3.PERICALLOSALARTERYA2:SEGMENTA2segment:thesegmentinferiortothecorpuscallosumwhichconvexanteriorlyThissegmentextendsfromtheACommtothebifurcationformingthe

pericallosal

andcallosomarginalarteries.The

recurrentarteryofHeubner

(distalmedialstriateartery),whichirrigatetheinternalcapsule,usuallyarisesatthebeginningofthissegmentneartheAComm.A2:SEGMENTTwobranchesarisefromthissegment,the:1）Orbitofrontalartery

(medialfrontalbasal):ArisesfirstasmalldistanceawayfromtheAComm2）Frontopolarartery

(polarfrontal):Arisesafterthe

orbitofrontal

closetowhenA2curvesposteriorlyoverthe

corpuscallosum.Couldalsooriginatefromthe

callosalmarginal.3.1Orbito-frontalarteryItalsocalledfrontobasalartery,orbitalartery,olfactoryartery.Itarisesdirectlyfromthemaintrunkofthepericallosalarteryneartheanteriorcommunicatingarterytosupplytherectusgyrus,orbitalgyrusandtheolfactorybulb.Inlateralprojectionsitrunsanteroinferiorlyneartheplanumsphenoidtoreachtheanteriorcranialfossa,parallelsoroverlapswiththeophtalmicartery;A-Pviewrevealsitscourseinfero-laterallyfromtheareaofanteriorcommunicatingartery3.2FrontopolararteryItarisesdistaltotheorbitofrontalarteryandrunsalongthemedialaspectofthecerebralhemisphere,andreachestheconvexsurfaceofthefrontalpole.A3SEGMENTA3segment:thesegmentalongthegenuofcorpuscallosumwhichconvexanteriorly;

A4SEGMENTThesegmentalongthesuperiormarginofthecorpuscallosumatthefrontallobe;ItincludesCallosomarginalarteryandpericallosalarterywhichextendsposteriorlyinthepericallosalsulcustoformtheinternalparietalarteries

(superior,inferior)andthe

precunealartery.CallosomarginalarteryItisoneofthemajorbranchesofthepericallosalarteryandsuppliestheanteromedialaspectofthesuperiorfrontalgyrusandthecingulategyrus.Whenthereisunderdevelopmentofthepericallosalartery,thecallosomarginalarterymaycompensateforitsbloodsupply.A5SEGMENT1Anteriormedialfrontalartery:suppliestheanterior1/3ofthemedialsuperiorfrontalgyrus;2Middlemedialfrontalartery:suppliesthemiddle1/3ofthemedialsuperiorfrontalgyrus;3Posteriormedialfrontalartery:suppliestheposteriorpartofthemedialsuperiorfrontalgyrusandtheparacentralgyrus,itmaysometimesoriginatetogetherwiththemiddlemedialfrontalarteryandtheparacentralarteryfromthecallosomarginalartery;A5SEGMENT4Paracentralartery:itsuppliestheparacentralgyrus,withsmallbranchestothecentralsulcus.5Superiormedialparietalartery:itoriginatesdirectlyfromthepericallosalartery,ormayarisefromthebranchesofthecallosomarginalarterytosupplythesuperiorpartoftheprecuneus.Itsbranchesenterthecingulategyrustoformanastomosiswiththeparieto-occiptalarteryfromtheposteriorcerebralartery.6Inferiormedialparietalartery:astheterminalbranchofthepericallosalartery,andmayarisefromthesuperiormedialparietalartery.Itsuppliestheinferior1/3oftheprecuneus.FunctionAreassuppliedbytheanteriorcerebralarteryinclude:1、Themedialsurfaceofthe

frontallobe

,andparietallobes2、Theanteriorfour-fifthsofthe

corpuscallosum3、Approximately1

inchofthelateralsurfacesoffrontalandparietallobes,nexttothe

mediallongitudinalfissure4、Anteriorportionsofthe

basalgangliaandinternalcapsule5、OlfactorybulbandtractOcclusionOcclusionoftheanteriorcerebralarterymayresultinthefollowingdefects:I