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THE ANATOMY AND PHYSIOLOGY OFTHE OPTHALMIC ARTERY

The Ophthalmic artery (OA)is the first branch of the internal carotiarter! istal to the ca"erno#s sin#s$ %ranches of the OA s#&&l! all the str#ct#res in

the orbit as 'ell as so(e str#ct#res in the nose) face an (enin*es$The OA

e(er*es fro( the internal caroti arter! #s#all! +#st after the latter e(er*es fro(

the ca"erno#s sin#s altho#*h in so(e cases) the OA branches +#st before the

internal caroti e,its the ca"erno#s sin#s$ The OA arises fro( the internal caroti

alon* the (eial sie of the anterior clinoi &rocess an r#ns anteriorl! &assin*

thro#*h the o&tic canal 'ith an inferolaterall! to the o&tic ner"e$ Here) it sho#l be

note that the o&hthal(ic arter! can also &ass s#&eriorl! to the o&tic ner"e in a(inorit! of cases$-./ In the &osterior thir of the cone of the orbit) the o&hthal(ic

arter! t#rns shar&l! (eiall! to r#n alon* the (eial 'all of the orbit$

The common carotid arteryis fo#n bilaterall!) 'ith one on each sie ofthe anterior nec0$ Each co((on caroti arter! is i"ie into an e,ternal an

internal caroti arter!$ These arteries transfer bloo to the str#ct#res insie an

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o#tsie the s0#ll$

The external carotid arterybrin*s bloo to str#ct#res o#tsie the

s0#ll) &ri(aril! the face) an the internal caroti to str#ct#res insie the s0#ll)

incl#in* the brain$

The internal carotid is res&onsible for s#&&l!in* bloo to the nearest

brain he(is&here 'ith the hel& of the basilar arter!$ The "ertebra1basilar s!ste(

s#&&lies bloo 'hen the caroti arter! cannot o so$ This arter! ascens alon* the

nec0) &assin* behin the ear into the s#barachnoi s&ace in the te(&oral loa$ It

i"ies into t'o branches) the (ile cerebral arter! an anterior cerebral arter!$

The e,ternal caroti arter! is strai*ht) b#t the internal caroti arter! t'ists an

t#rns) increasin* the li0elihoo of bloc0a*es$

The Left and Right Common Carotid Arteries are arteries that

s#&&l! the hea an nec0 'ith o,!*enate bloo2 the! i"ie in the nec0 to for(the e,ternal an internal caroti arteries$The co((on caroti arter! is a &aire

str#ct#re) (eanin* that there are t'o in the bo!) one for each half$ The left an

ri*ht co((on caroti arteries follo' the sa(e co#rse 'ith the e,ce&tion of their

ori*in$ The ri*ht co((on caroti ori*inates in the nec0 fro( the brachioce&halic

tr#n0$ The left arises fro( the aortic arch in the thoracic re*ion$ The bif#rcation into

the e,ternal an internal caroti arteries occ#rs at the #&&er borer of the th!roi

cartila*e) at aro#n the le"el of the fo#rth cer"ical "ertebra3C45$The left co((on

caroti arter! can be tho#*ht of as ha"in* t'o &arts6 a thoracic 3chest5 &art an a

cer"ical 3nec05 &art$ The ri*ht co((on caroti ori*inates in or close to the nec0) so

contains a s(all thoracic &ortion$

The Anterior Cerebral Artery s#&&lies (ost of the s#&erior (eial&arietal lobes an &ortions of the frontal lobes 'ith bloo$ Anterior cerebral arteries

s#&&l! bloo to the frontal lobes7 anterior as&ects) areas res&onsible for hi*her le"el

co*nition incl#in* +#*(ent an reasonin*$ This arter! ori*inates at the internal

caroti an tra"els at a ri*ht an*le 'ith &enetratin* branches s#&&l!in* bloo to

"ario#s &arts of the brain$ This arter! s#&&lies bloo to the se&tal area) the cors

callos#() &ri(ar! so(atosensor! corte,es for the foot an le*) the frontal lobes7

(otor &lannin* areas) an the #rinar! blaer$ The anterior cerebral arter! is a

co(&onent of the Circle of 8illis) an arterial anasto(atic tr#n0 in the brain$

The Middle Cerebral Arteryis the lar*est of the three (a+or arteries thatistrib#tes bloo to the cerebr#($ It is fo#n in the internal caroti$ %loo is

s#&&lie to lateral areas of the frontal) te(&oral) an &arietal lobes$ The frontal)

te(&oral) an &arietal lobes control the sensor! f#nctions of the ar(s) throat)

hans) an face$ The &arts of the (ile cerebral arter! are6 Hori9ontal se*(ent6

Creates holes 'ith lateral lentic#lostriate arteries$ These arteries are res&onsible for

irri*atin* the basal *an*lia S!l"ian se*(ent6 S#&&lies bloo to the te(&oral lobe

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an ins#lar corte,$ The branches (a! i"ie or bif#rcate or trif#rcate into tr#n0s$

This se*(ent also contains the o&erc#l#() 'hich e,ten fro( the ins#la in the

irection of the corte,$ Cortical Se*(ents6 &ro"ies irri*ation for the corte,

In the brain) o,!*enate bloo tra"els thro#*h an e,tensi"e an central

cerebral arterial circle$ This net'or0 is also calle the circle of 8illis$

The posterior communicating artery (a0es #& a lar*e &art of thecircle7s lo'er half$ The circle is s!((etrical) so there are t'o &osterior

co((#nicatin* arteries) each has a left or ri*ht esi*nation$ %oth are con#its

bet'een lar*er bloo "essels) connectin* the (ile cerebral arter! 'ith the

&osterior cerebral arter!$ E"ent#all!) this +oins into the basilar) 'hich s&lits into t'o

"ertebral arteries$ Since the cerebral arterial circle is so central in the brain) arterial

&roble(s (a! ha"e rastic conse:#ences$ The &osterior co((#nicatin* arter! is

often the site of ane#r!s(s$ Most ane#r!s(s occ#r in the anterior co((#nicatin*

arter!) b#t in ter(s of fre:#enc!) the &osterior co(es in secon$ The arter!

e"elo&s late #rin* fetal *estation as e(br!onic "essels be*in to f#se to*ether$