the syndromes of the arteries the brain and spinal...

65

THE SYNDROMES OF THE ARTERIESOF THE BRAIN AND SPINAL CORD

Part 1

By LESLIE G. KILOH, M.D., M.R.C.P., D.P.M.First Assistant in the Joint Department of Psychological Medicine, Royal Victoria Infirmary and University of Durham

IntroductionLittle interest is shown at present in the syn-

dromes of the arteries of the brain and spinal cord,and this perhaps is related to the tendency tominimize the importance of cerebral localization.Yet these syndromes are far from being fullyelucidated and understood. It must be admittedthat in many cases precise localization is often oflittle more than academic interest and providesnothing but a measure of personal satisfaction tothe physician. But it is worth recalling that thedetailed study of the distribution of the bronchiand of the pathological anatomy of congenitalabnormalities of the heart, was similarly neglecteduntil the prospect of therapeutic applicationdemonstrated the fallacy of this attitude.

Cerebral thromboses are usually the expressionof diffuse vascular disease and often it is neitherpossible nor profitable to implicate named vessels.Optimistic conclusions have often been expressedin the past regarding the specific effects of occlusionof one particular vessel, but are difficult to acceptin view of the ultimate demonstration of multiplelesions. Cases of cerebral embolism would seemto provide a better prospect of accurate study butare less common; many vessels are seldom, ifever, involved and the opportunity of makingpathological studies becomes very remote whenthe smaller-and in many respects more interesting-vessels are affected. Cerebral angiography mayin the future offer an alternative to post-mortemexamination and provide a chance of identifyingthe site of the primary occlusion at a time when theclinical picture remains uncomplicated. Suchstudies as that made by Ethelberg (I95I) of theanterior cerebral artery, are likely to lead to arapid expansion of our knowledge of these syn-dromes.The varied effects of occlusion of any particular

artery in different individuals depends on severalfactors. The extent of the territory supplied andthe efficacy of the collateral circulation differwidely from person to person. The degree of

general circulatory efficiency at the time of thecatastrophe is of the greatest importance. Anocclusion, producing little effect in the presence ofa normal blood pressure, may cause widespreadpathological changes if hypotension co-exists.A marked discrepancy has been noted between

the effects of ligation and of spontaneous throm-bosis of an artery. The former seldom producesill effects whilst the latter frequently determinesinfarction. This is probably due to the tendencyof a spontaneous thrombus to extend along theaffected vessel, sealing its branches and blockingits collateral circulation, and to the fact that thearterial disease is so often generalized.

In this paper the various syndromes resultingfrom occlusion of the arteries of the brain andspinal cord will be described in the light of ourpresent knowledge. The pathology of the occlusiveprocess will not be considered, nor will theslowly developing syndromes due to diffusecerebrovascular disease be discussed. Theanatomy and distribution of the vessel in questionwill be outlined briefly before its syndromes aredescribed.

Internal Carotid ArteryThe internal carotid artery enters the skull

through the carotid canal and runs forwardsthrough the cavernous sinus to the medial aspectof the anterior clinoid process. Here it turnsupwards and at the commencement of the Sylvianfissure divides into its terminal branches-theanterior and middle cerebral arteries.The results of occlusion of the internal carotid

artery are extremely varied. The condition is achance finding at arteriography in a number ofpatients who have none of the anticipated symp-toms or signs. Certainly surgical ligation of thevessel-if proper precautions are taken-rarelygives rise to any disability.When symptoms do occur, the onset is often

gradual. Persistent headache of a migrainouscharacter on the same side as the thrombosis may

copyright. on 8 July 2018 by guest. P

rotected byhttp://pm

j.bmj.com

/P

ostgrad Med J: first published as 10.1136/pgm

j.29.328.65 on 1 February 1953. D

ownloaded from

http://pmj.bmj.com/

66 POSTGRADUATE MEDICAL JOURNAL February I953

occur for years before other features develop.Transient attacks of focal weakness, of focalparaesthesiae or of dysphasia are common andrarely generalized convulsions may occur. Thesuggestion has been made that these transientdisturbances result from spasm of the smallercerebral vessels reflexly induced by impulses fromnerve endings in the wall of the diseased internalcarotid artery. In other cases an acute onset isseen. The left internal carotid is affected muchmore frequently than the right.The full syndrome that might be expected on

anatomical grounds is seen only occasionally.Ipsilateral anosmia is sometimes present. Thereis blindness of the ipsilateral eye--which may betransient-due to involvement of the ophthalmicartery, while the opposite eye shows a temporalfield defect due to a lesion of the optic tract andradiation, Optic atrophy develops in the blind eye.A severe contralateral hemiplegia and hemi-anaesthesia are also present, together with a severedysphasia if the major hemisphere is affected.Although mental changes of the organic reactiontype have been attributed to occlusion of the inter-nal carotid artery, their occurrence is so haphazardas to suggest that their presence is coincidental.

Cases of lesser severity are far more numerous.The most common picture is that of a moderatelysevere hemiplegia accompanied by a hemi-anaesthesia of lesser severity with astereognosisand some degree of dysphasia. It is obvious thatthere may be nothing characteristic about thecondition and its differentiation, particularly fromocclusion of the middle cerebral artery or one ofits branches, can only be made by carotid arterio-graphy.

(See Elvidge and Werner, 195i; Fisher, I95I.)The Anterior Cerebral ArteryFrom its origin at the medial end of the Sylvian

fissure, the anterior cerebral artery runs forwardsand medially across the anterior perforated sub-stance and above the optic nerve to the marginbetween the medial and orbital surfaces of thefrontal lobe. At this point the vessels of eitherside are connected by the anterior communicatingartery. Each then turns abruptly upwards toreach the genu of the corpus callosum and runsbackwards in the depths of the longitudinal fissure,finally emerging from it to end in the quadratelobe or the parieto-occipital fissure. Branches:

(a) Basal: (i) Several fine branches enter theanterior perforated substance and supply the headof the caudate nucleus. (ii) Recurrent artery(artery of Heubner). This pierces the lateral ex-.tremity of the anterior perforated substance andpasses upwards and outwards to supply theanterior part of the caudate nucleus, the anterior

third of the putamen, the outermost part of theglobus pallidus and the anterior limb of the internalcapsule.

(b) Anterior communicating artery-which oftengives off a few twigs to the optic chiasma and in-fundibular region (Rubenstein, I944).

(c) Branches from the convexity: (i) Prefrontalor orbital branch supplying the medial aspect ofthe frontal lobe. (ii) Frontopolar branch-to themost anterior portion of the superior frontalgyrus. (iii) Calloso-marginal artery which dividesinto anterior, middle and posterior internalfrontal branches supplying the medial portion of'the convexity of the frontal lobe. (iv) Paracentralartery-to the paracentral lobule. (v) Superiorparietal branch. (vi) Precuneal branch-to the*region of the quadrate lobule. (vii) Parieto-occipital branch.

(d) Branches from the concavity: (i) Numeroustwigs to the corpus callosum and to the anteriorpillars of the fornix. (ii) Pericallosal artery whichlies deep to the anterior cerebral artery and con-tinues the line of this vessel.

Occasionally both anterior cerebral arteries arisefrom the same internal carotid and sometimes onlyone vessel is present.Occlusion of the Main Trunk Proximal to Heubner'sArteryMuch depends on the size of the anterior com-

municating artery. If this is large and notobstructed by the thrombus, occlusion of themain trunk of the anterior cerebral artery willeither produce no ill effects or give rise to a syn-drome similar to that following thrombosis ofHeubner's artery. If the collateral circulation isinadequate the resulting syndrome is much moreserious. In most cases consciousness is lost.Dandy (I930) as the result of some unfortunateexperiences following the tying of the left anteriorcerebral artery, maintained that total occlusion ofthis vessel always resulted in stupor or coma fromwhich recovery did not occur. Many cases havesince been recorded in which ligation produced noill effects (Poppen, I939). Major convulsions mayoccur and the eyes and head may be turned tothe side of the lesion due to the unbalanced actionof the opposite frontal eye field (area 8). Whenthe patient is conscious it may also be found that hehas some defect of lateral conjugate movement ofhis eyes to the opposite side because of the damageto the ipsilateral eye field. These features areshort-lived and disappear in a few days or weeks.

Mental changes--including all the organic re-action types-may occur and are regarded by someauthors as a specific part of the clinical picture, butthis cannot be maintained. Patients showing theseconditions are usually old and have diffuse



j.bmj.com

/P


j.29.328.65 on 1 February 1953. D

ownloaded from

http://pmj.bmj.com/

February 1953 KILOH: The Syndromes of the Arteries of the Brain and Spinal Cord 67

v Para ce ntraLCaZZosomargtnal Peric'losalPrr etonitrlerSip.Parietlsl ~ ''

;!.

Anterior cerebral /..Postenor tempoa \

Posor cre Anerior epor C re

Poterior cerebral /."·alro . . · / . ',,An~i" emprd C~l~r'i e

FIG. I.-Medial aspect of right cerebral hemisphere showing distribution of cortical branchesof anterior, middle and posterior cerebral arteries. (The paracentral branch in this case comesoff the calloso-marginal artery.) (de Jong, 1950, ' The Neurologic Examination,' Cassel & Co.,

London.)

cerebrovascular disease. Of Ethelberg's 2o cases,seven only showed some memory disturbance andshallowness of affect. Bilateral occlusion of theanterior cerebral arteries is of course much morelikely to be associated with dementia-usuallyaccompanied by a placid euphoria-but diffusearterial disease is invariably present too.A severe hemiplegia results from the combined

effects of lesions of the anterior limb of the internalcapsule and of the paracentral lobule. The faceand limbs are involved more or less in equaldegree, though either limb may be differentiallyaffected in some cases. After the initial period of'shock' the hemiplegia becomes spastic. Vaso-motor and trophic changes are commonly marked.The skin is cold and blue and chronic oedema maybe present. Dystrophic changes in the skin, nails,subcutaneous tissues and joints may follow.

Sensory loss of a cortical type is present in thelower limb due to the lesion of the paracentrallobule and is most marked distally. Occasionallysimilar loss is present in the arm. Some urgencyor frequency of micturition is common.When the major hemisphere is affected, some

degree of dysphasia of an expressive type is

common initially but rarely persists for more thana few weeks. Ethelberg (I95I) maintains that thespeech disturbance is not a true dysphasia but an'impairment of rapid sequential movements ofthe speech organs' and is therefore a corticallydetermined dysarthria. In these cases a dyspraxia-usually ideomotor in type-is found on the sideopposite to the paralysis. Theoretically, thedyspraxia is bilateral but on the hemiplegic sideis masked by the paralysis.' It is supposedly due toinfarction of the anterior portion of the corpuscallosum which interrupts the commisural fibreslinking the premotor and motor areas of the majorto the minor hemisphere. This portion of thecorpus callosum has, however, been divided sur-gically on many occasions without producingdyspraxia, and it was pointed out by Akelaitis etal. (I942) that this condition occurred only if themedial aspect of the dominant frontal lobe was alsodamaged. Ethelberg, though not denying theexistence of a true ideomotor dyspraxia, pointedout that in his patientis the disability was simplya clumsiness, particularly when performing rapidand complex movements. He felt therefore that itshould be regarded as an ' impairment of rapid



j.bmj.com

/P


j.29.328.65 on 1 February 1953. D

ownloaded from

http://pmj.bmj.com/

68 POSTGRADUATE MEDICAL JOURNAL' February 1953

sequential movements.' This particular descrip-tion, however, would appear remarkably close toLiepmann's 'limb kinetic apraxia.' The dis-turbance is transient as a rule for the minorhemisphere becomes accommodated.

Occlusion of the Main Trunk beyond Heubner'sArtery

Loss of conscipusness is less frequent than withobstruction at the commencement of the artery.The contralateral paresis is highly characteristicand affects predominantly or exclusively the lowerlimb. When the upper limb is affected the weak-ness is most evident around the shoulder and inthe upper arm-a state designated as a ' dis-sociated hemiplegia' by Dimitri and Victoria(I936)-differing from the usual type of hemiplegiain which the weakness is maximal peripherally. Inaddition, the hemiplegia usually remains flaccidwith diminished or absent deep reflexes. Thereason for this is unknown, but it has beensuggested that it is because the deeper structures,including the basal ganglia, are unaffected.Fulton's suggestion, made in another context,that a hemiplegia due to a lesion of area 4 isflaccid and becomes spastic only when area 6 isalso affected, scarcely seems applicable here for theanterior cerebral artery supplies equivalent partsof both these areas.

Sensory loss of a cortical variety is present inthe contralateral lower limb and is more markeddistally. A sensory ataxia of this limb resultsand may be disabling.

Sometimes the upper limb though showinglittle or no paralysis may be clumsy and the signsof a 'cerebellar '- dyssynergia may be demon-strable. These are slight or moderate in degreeand are attributed to damage to the fronto-pontine tract.A grasp reflex, sometimes with forced groping,

may be found on the same side as the hemiplegiabut only when-the weakness of the upper limb isrelatively slight. An increased Mayer's reflex isalso present in the affected hand (Hyland, I933).Such a finding is of localizing value. Of lesssignificance is the presence of a bilateral graspreflex, often with a sucking reflex on stimulation ofthe lips. Such cases often show catatonic featuresand one of Baldy's patients (1927) also hadecholalia and palilalia. These features probablyoccur only with widespread disturbance ofcerebral function.A transient expressive dysphasia and dyspraxia

may appear when the lesion involves the dominanthemisphere.

If both anterior cerebral vessels become occluded(or if their function is subserved by a singlevessel which is thrombosed) bilateral paralysis of

the lower limbs occurs, together with corticalsensory loss. As a result of the latter there may beconsiderable sensory ataxia which is aggravated byeye closure or darkness. Precipitancy and fre-quency of micturition are marked. A lesion of thespinal cord is therefore simulated but in most casesthe onset is episodic, first one side then the otherbeing affected. Many, too, will show varyingdegrees of organic deterioration. If the area ofinfarction is extensive enough to involve the corti-cobulbar fibres or their cells of origin, pseudo-bulbar phenomena result, causing difficulty indifferentiation from a brain stem lesion.Occlusion of Heubner's Artery

Occlusion of Heubner's artery gives rise toweakness of the contralateral face and upper limb.Transient weakness of the tongue and palate maybe seen. In the upper limbs the weakness is some-times more marked proximally. Some tremor orhyperkinesis of the affected arm may occur butthere is doubt as to whether this is due to in-volvement of the frontopontine tract or of the basalganglia. A moderate degree of expressive dys-phasia is present if the lesion affects the majorhemisphere. Apraxia and sensory loss do notoccur.Paracentral Artery

Occlusion of the paracentral artery gives rise toweakness of the lower limb which is usually severeand more marked distally. Slight weakness ofthe upper limb and even of the face may occasion-ally co-exist. The monoplegia may be flaccid orspastic and as a rule is accompanied by sensoryloss of the cortical type. Trophic changes are oftenmarked. Neither dysphasia nor a grasp reflexoccurs.

Occlusion of other branches of the anteriorcerebral artery and of the main stem of the vessel atvarious points has been found post-mortem in anumber of cases. In life, however, there wasnothing characteristic in the clinical pictures todifferentiate them from occlusion elsewhere in thedistribution of this artery. A hemiplegia withcrural dominance of sudden onset is always highlysuggestive of occlusion of some part of the anteriorcerebral system. The only other vascular lesionwhich has a similar result is thrombosis of theRolandic vein.

(See Critchley, 1930; Foix and Hillemand,1925a.)Middle Cerebral Artery (Sylvian Artery)The middle cerebral artery is the largest branch

of the internal carotid artery and arises at thecommencement of the Sylvian fissure in which itruns. Branches:

Perforating or central vessels. These are given



j.bmj.com

/P


j.29.328.65 on 1 February 1953. D

ownloaded from

http://pmj.bmj.com/


.. '~Roltantc,. 'An'eriorpai'da ?terwrparire(di

·and"'..· . ' t. .

Hil

Pre-~olan.iC r "Y'.

AMiddle iC-rebu,gu,

', ;

A rA-.r,..-j

r:·:r·~~,"',

" ",lb~~bE. '"";r;'j~ c\.M~dlccrr66~2i i' ,~~..'

A~fr;9"tnait C·Pl(I~LLd

FIG. 2.-Lateral aspect of left cerebral hemisphere showing distribution of the cortical branchesof the anterior, middle and posterior cerebral arteries. (de Jong, 1950, ' The NeurologicExamination,' Cassel & Co., London).

off at right angles to the main vessel and penetratethe anterior perforated substance. They are saidnot to anastomose with one another. They varyin number and are arranged in two sets-themedial striate and lateral striate groups. Togetherthese supply the lentiform nucleus, the caudatenucleus, the posterior portion of the anterior limb,the genu and the anterior third of the posteriorlimb of the internal capsule. The 'artery ofcerebral haemorrhage' so much emphasized byCharcot, is a member of the lateral striate groupand is sometimes termed the lenticulo-striateartery.

Cortical branches. The following vessels maybe distinguished, though two or more frequentlyarise from the main vessel by a common stem:-

Anterior temporal artery-supplies the anteriorthird of the superior and middle temporal gyri andthe insula.

Orbitofrontal artery-supplies the inferomedialand inferolateral aspects of the frontal lobe.

Prerolandic artery-to the lower part of the pre-central gyrus and adjacent frontal cortex.

Rolandic artery--to the precentral and post-central gyri.

Anterior parietal artery-to the postcentralgyrus and the adjacent parietal cortex.

Posterior parietal artery-to the posterior por-tion of the parietal lobe and the supramarginalgyrus.

Artery of the angular gyrus-continues the lineof the main vessel and supplies the angular gyrusand the adjacent parietal cortex.

Posterior temporal artery-to the posterior two-thirds of the lateral surface of the temporal lobe.These vessels form anastomoses with branches

of the anterior and posterior cerebral arteries.There is no doubt that occlusion in the territory

of the middle cerebral artery may occur withoutproducing symptoms or signs. In other casestransient headache, giddiness, confusion and focalsigns result but disappear rapidly and leave nosequelae. In a number of cases focal or generalizedfits are seen at the onset.

Occlusion -of the Main Stem of the Middle CerebralArtery

Occlusion of the first part of the middle cerebralartery results in profound coma which frequentlyproves terminal. The thrombosis may commencein one of its branches and extend back to the mainartery, so that progression of symptoms occursover a period of hours or days. When adequateexamination is possible, a severe contralateral totalhemiplegia quickly becoming spastic, a hemi-



j.bmj.com

/P


j.29.328.65 on 1 February 1953. D

ownloaded from

http://pmj.bmj.com/

70 POSTGRADUATE MEDICAL JOURNAL February 1953

anaesthesia and a homonymous hemianopia can bedemonstrated. If the major hemisphere is affecteda severe global aphasia is also present.

Anosognosia, in which the paralyzed body halfis ignored and even disowned, is often to beobserved during the period of recovering con-sciousness when the minor hemisphere is the siteof the lesion.

In survivors the residual disability is severe andcontractures develop. Some retrogression of thesensory loss may occur.

Perforating BranchesThe medial and lateral striate vessels are

probably more subject to occlusion than any ofthe other cerebral arteries. Consciousness isusually retained. A contralateral spastic hemi-plegia is constant, the weakness being equal in thetwo limbs or occasionally more obvious in the leg.The severity of the hemiplegia varies widely fromcase to case. Disturbances of sensation in theaffected body half are occasionally present butare seldom severe. A hemianopia due to in-farction of the optic radiation at its commence-ment is rare and is, in fact, more commonly theresult of occlusion of the superficial branches ofthe middle cerebral artery. When the majorhemisphere is affected, a dysphasia-expressive orless frequently global in type-is often found andis attributed to oedema of the overlying con-volutions (Davison et al., 1933). In most casesconsiderable recovery of speech function ensues.

Bilateral occlusion of the perforating branchesof the middle cerebral artery is the commonestcause of pseudobulbar palsy.Superficial Branches

Isolated occlusion of the individual superficialbranches of the middle cerebral artery is relativelyuncommon and it is more usual to find two ormore affected, as might be expected from theircollective mode of origin. To some-the anteriortemporal artery for example-no syndrome canas yet be ascribed. The majority of these casesfall into one of two groups, those with involvementof the more anteriorly placed branches and thosewith involvement of the posterior branches. It isoften unprofitable to attempt to analyze thesecases further.

Anterior group. Occlusion of the anterior groupof vessels gives rise to a contralateral hemiplegiaaffecting particularly the face and upper limb, theweakness in the latter being most marked distally.Frequently the hemiplegia remains flaccid. Somecortical sensory loss with astereognosis is alsopresent in the upper limb. If the major hemi-sphere is involved, a dysphasia occurs which isusually expressive in type but may show mixed

features. It is commonly severe and enduring. Asevere irreversible dysphasia resulting from vascu-lar occlusion is always highly suggestive of a lesionof the middle cerebral artery. The extent ofrecovery depends not only on the severity of thedamage but on the degree of dominance of themajor hemisphere and on the age of the patient. Alesion occuring before the age of five years seldomleads to a permanent dysphasia.

Occasionally if the paresis is slight, dyspracticphenomena of an ideomotor type can be detectedbut are short-lived.

Posterior group. The most striking feature dueto occlusion of the posterior group of vessels is acontralateral homonymous hemianopia. The fielddefect may at times be limited to the inferiorquadrants. It is the result of a lesion of the opticradiation, for the superficial branches supply thesubcortical white matter to a varying depth as wellas the cortex itself. When the major hemisphereis affected the hemianopia is accompanied by abilateral ideomotor or ideational dyspraxia. Thevarious disturbances of the body scheme discussedbelow under ' posterior parietal artery' are alsolikely to be present.

If the anterior parietal branch is also affected,a contralateral hemiplegia of moderate degree-again due to involvement of subcortical whitematter-and some cortical sensory loss over thecontralateral body half are also present.

It may be very difficult to distinguish betweenthe effects of occlusion of the superficial and deepbranches of the middle cerebral artery. In theformer the weakness is likely to be greater in theupper limb; particularly if it commences in theupper limb and spreads to the lower, a corticalorigin is likely. If the hemiplegia remains per-sistently flaccid the occlusion is almost certainlysuperficial. Marked sensory changes and thepresence of a field defect also favour a superficialocclusion.The results of occlusion of the individual super-

ficial branches of the middle cerebral artery willnow be discussed, but it must be emphasized thatsome of the descriptions are based on rather meagredetails.

Orbitofrontal artery. On the major side an ex-pressive dysphasia without paresis may followocclusion of this branch. Occasionally weaknessof the opposite face and tongue may be demon-strable but this is apparent only, and is, in fact,dyspractic in nature. Such a patient may beunable to protrude his tongue or whistle to order.If the lesion affects the minor hemisphere nolocalizing signs result.

Prerolandic artery. Occlusion of this vessel givesrise to contralateral weakness of'the lower face andtongue. The limbs as a rule are spared completely



j.bmj.com

/P


j.29.328.65 on 1 February 1953. D

ownloaded from

http://pmj.bmj.com/

February x953 KILOH: The Syndromes of the Arteries of the'Brain and Spinal Cord

CCIC

ocm a

M C P.~ ·ki8i~ ~~'S1, ''

Mc~

\bm001

FIG. 3.-The arteries at the base of the brain.

AC Anterior cerebral artery.aca Anterior chorioidal artery.a cl. p Anterior clinoid process.acm Anterior communicating artery.B Basilar artery.IC Internal carotid artery.MC Middle cerebral artery.PC Posterior cerebral artery.

pca Posterior communicating artery.sba Basal branches of anterior cerebral artery.sbm Perforating branches of middle cerebral

artery.SC Superior cerebellar artery.VA Vertebral artery.(After Buchanan, I948, 'Functional Neuro-anatomy,' Henry Kimpton, London.)

but weakness limited to the hand may sometimesbe seen. An expressive dysphasia, varying greatlyin intensity from case to case, is also present whenthe major hemisphere is affected.

Rolandic artery. Lesions due to isolatedocclusion of this artery are rare because of therichness of the collateral irrigation of its territory.Paresis of the contralateral upper limb-and to alesser extent of the face-develops, together withsome degree of cortical sensory loss in the samedistribution. A slight expressive dysphasia occurswith lesions of the major hemisphere.

Anterior parietal artery. Cortical sensory lossin the contralateral upper limb and face is the moststriking feature following occlusion of this branch.

It is accompanied by astereognosis and a sensoryataxia. Pseudoathetotic movements sometimesoccur in the affected limb when the eyes are closed.Signs of a slight pyramidal tract disturbance anda mild degree of dysphasia may be present.

Posterior parietal artery and the artery of theangular gyrus. Occlusion of these vessels on eitherside may give rise to a contralateral homonymousor inferior quadrantic hemianopia. Disturbancesof the body scheme are found, particularly whenthe major hemisphere is affected. The preciseform of the disturbance varies greatly from patientto patient but the. most common finding is aGerstmann's syndrome comprising dysgraphia,dyscalculia, finger agnosia and confusion of



j.bmj.com

/P


j.29.328.65 on 1 February 1953. D

ownloaded from

http://pmj.bmj.com/

72 POSTGRADUATE MEDICAL JOURNAL February I953

laterality (right-left disorientation). These phe-nomena may occur independently of one another.Other agnostic features may be present-a visualagnosia or an agnosia for colours-and the autoto-pagnosia, of which the finger agnosia is an ex-pression, may be more profound so that thepatient is unable to recognize any part of his body(Nielson, 1946). A bilateral ideational or ideo-motor dyspraxia is also frequently present. Adysphasia, predominantly receptive in character,usually occurs and a dyslexia is its most prominentfeature.

(See Foix and Levy, 1927; Tichy, I949.)The Anterior Chorioidal ArteryThe anterior chorioidal artery arises from the

internal carotid artery near its termination. Itruns backwards in close relationship with the optictract between the uncus and the cerebral peduncleto the lower end of the chorioidal fissure. Itsupplies the uncus and the optic tract, the middlethird of the cerebral peduncle, most of the globuspallidus, the posterior two-thirds of the inferiorhalf of the posterior limb of the internal capsule,the anterior half of the subthalamic nucleus, thered nucleus and the lateral aspect of the externalgeniculate body.

Proven examples of occlusion of the anteriorchorioidal artery are few. Loss of consciousness isunusual. A contralateral hemiplegia is constantand either affects the entire body half equally orthe lower limb predominantly. In the former caseit is probable that the lesion of the cerebralpeduncle is pre-eminent whilst in the latter,damage to the internal capsule is mainly re-sponsible. Contralateral impairment of all formsof sensation and a homonymous hemianopia arealso present. When the hemianopia is complete itis said that the lesion responsible affects the in-ternal capsule, while if it be a superior quadranticdefect, infarction of the lateral geniculate body isindicated (Abbie, 1933). Although considerabledestruction of the caudate nucleus may occur, thisproduces no characteristic signs.The combination of a hemiplegia, hemi-

anaesthesia and hemianopia also occurs followingocclusion of the trunk of the middle cerebralartery or a haemorrhage into the internal capsule.In such cases the result is far more grave. Deepcoma will be present and the hemiplegia is verymuch more severe than that following occlusion ofthe anterior chorioidal artery.

(See also Steegman and Roberts, 1935.)Posterior Communicating ArteryThis vessel arises from the internal carotid

artery a short distance before its termination andpasses backwards to join the posterior cerebral

artery. Branches are given off to the optic chiasma,the tuber cinereum, the medial aspect of thethalamus, the anterior portion of the posteriorlimb of the internal capsule and the rostral thirdof the pes pedunculi.The syndromes resulting from occlusion of this

vessel have not been defined. Brock (1937) hasreported that a contralateral mimetic palsy of theface may result.The anterior lobe of the pituitary is supplied

principally by the superior hypophyseal vesselswhich arise directly from the internal carotidarteries. Some twigs of supply come from theposterior communicating arteries. Occlusion ofthese vessels may give rise to Simmond's disease.

Posterior Cerebral ArteryEach posterior cerebral artery winds backwards

round the cerebral peduncle and passes deep tothe splenium of the corpus callosum to reach themedial border of the inferior surface of the tem-poral lobe where it divides into terminal or cor-tical branches. Developmentally, the posteriorcerebral artery beyond its junction with theposterior communicating artery is derived from theinternal carotid artery (Williams, 1936).

Branches: Paramedian group (retromamillarybranches). There are about Iz of these. Theanterior vessels-the thalamo-perforating or medialganglionic branches-enter the posterior perforatedsubstance and terminate in the medial portion of thethalamus; they also supply the mamillary body.The posterior vessels-peduncular branches-supply the cerebral peduncle, the substantia nigra,the third nerve nucleus and the posterior half of thesubthalamic nucleus. There is little anastomosisbetween the vessels of the two sides.

Quadrigeminal artery. This is a small vesselwhich winds round the midbrain and supplies itslateral aspect and the superior and inferiorcolliculi.

Posterior chorioidal artery. This vessel windsround the midbrain and after running over thesuperior aspect of the thalamus, ends in thechorioid plexus of the third ventricle. Six orseven branches are given off to the cerebralpeduncle and other twigs supply the superiorcolliculus and the internal and external geniculatebodies.

Geniculate arteries (thalamogeniculate arteries".These penetrate the external geniculate body,supplying it and the superior colliculus beforeentering the thalamus. The territory of supplyincludes the posterior half of the thalamus andthe posterior portion of the posterior limb of theinternal capsule.

Cortical branches: Anterior temporal, posteriortemporal, calcarine and parieto-occipital.



j.bmj.com

/P


j.29.328.65 on 1 February 1953. D

ownloaded from

http://pmj.bmj.com/


As might be expected from its distribution,there are many syndromes associated with lesionsof the posterior cerebral artery and its branches.When there is infarction of the cerebral hemi-sphere, focal.or generalized convulsions may occurat the onset and sometimes recur. Visual auraeare common.

Occlusion of the Main Trunk of the PosteriorCerebral ArteryvThe results of occlusion of the main stem of the

posterior cerebral artery depend largely on theadequacy of the posterior communicating artery.ANo ill effects may follow i f this latter vessel pro-vides an adequate collateral circulation. Wheninfarction does occur, consciousness is usually re-tained though occasionally persistent somnolentstates result (Bacaloglu et al., I934) possibly dueto damage to the reticular substance in the teg-mentum of the midbrain. A contralateral hemi-plegia is present but is moderate in degree. It isdue to infarction of the cerebral peduncle. Themost important and characteristic finding is acontralateral ' thalamic syndrome '-first des-cribed by Dejerine and Egger (I903) and againwith pathological studies by Dejerine and Roussy(I906). Paroxysmal or constant pain is presentin the affected body half including the face. As arule it is severe and often has a burning quality.It usually occurs spontaneously but may be pro-voked by heat, cold, movement or deep pressure.Pricking or icy cold sensations may be experienced.Although commonly diffuse, the pain may some-times be sufficiently localized to simulate abdominaldisease. Rectal or vesical pain associated withtenesmus or strangury is not uncommon.The objective sensory findings vary from case

to case, and in general their Severity is inverselyproportional to the amount of pain. Typicallythere is impairment of the sense of passive move-ment, of deep sensation and vibration sense. Pain,touch and temperature sensations on casualexamination appear to be unaffected and theoccurrence of hyperaesthesia or hyperpathia mayeven suggest an increased sensitivity. More care-ful examination reveals that the threshold value ofthe stimulus is raised and its localization is poor.Sometimes the response to pleasurable stimuli isalso exaggerated and such things as music whichproduce a general affective tone may evoke a re-action on the altered side so intensely pleasurableas to be unbearable. One of Head's patientsbecame somewhat amorous after his ictus and re-marked that his affected side had become moreresponsive and more desirous of solace. Theessential lesion was shown by Roussy to affect theposterior third of the lateral nucleus of thethalamus.

The extremities on the affected side oftenbecome oedematous and cyanosed while trophicchanges may develop in the finger nails. Thesechanges, though associated with the hyperpathia,are not necessarily of equivalent intensity.

Because of the impaired joint sense the affectedlimbs show a sensory ataxia and astereognosis.The ataxia is accentuated if the superior cerebellarpeduncle is damaged and contralateral cerebellarsigns may be demonstrable.

Various features due to destruction of extra-pyramidal structures or their connections-notably the substantia nigra, the red nucleus andthe subthalamic nucleus-are frequently present.The limbs may show a plastic rigidity and the armis held flexed at the elbow and a little flexed at thewrist, with fingers extended or hyperextended(thalamic hand). When walking, the arm may beheld extended and internally rotated with the handbehind the back. Movements of a choreic orathetoid nature may be present and are accentuatedby emotion and often by voluntary movements ofthe normal limb. In the latter case mirror move-ments may be seen. Tremor occurs rarely(Langworthy and Fox, 1937).

Other signs may result from midbrain damage.An ipsilateral third nerve palsy or a defect ofsuperior conjugate ocular movement (Parinaud'ssyndrome) sometimes occurs. An ipsilateralHorner's syndrome is more common than either.

Lastly, there may be evidence of damage to theoccipital and posterior parietal and temporal areasof cortex. A contralateral homonymous hemi-anopia which is usually complete occurs butsometimes there is apparent sparing of the maculae.There is no evidence to support the suggestion thatthe maculae are represented bilaterally, nor is theview tenable that the macular areas are supplied bybythe middle cerebral arteries. It is more probablethat so-called macular sparing is an artefact due toshifting fixation by the patient.

If the lesion affects the major hemisphere adysphasia is also present. In general this is re-ceptive in type but it is rarely severe. Oftenreading is particularly affected so that the defectapproaches closely to a pure alexia. Visualagnosia may also be present and very occasionallythere is visual autotopagnosia, which is more oftenpartial than complete.

The paramedian branches. Corresponding to theshort circumferential branches at lower levels aretwigs given off to the lateral aspect of the midbrainby the various branches of the posterior cerebralartery. They are not so clearly defined as thecorresponding vessels in the lower brain stem andas yet it is not possible to ascribe any particularsyndromes to their occlusion. It is probable thatthey play a part in some of the syndromes des-



j.bmj.com

/P


j.29.328.65 on 1 February 1953. D

ownloaded from

http://pmj.bmj.com/

74 POSTGRADUATE MEDICAL JOURNAL February '953

cribed below as the result of obstruction of thevarious paramedian branches.

(a) Rubrothalamic syndrome (superior syn-drome of the red nucleus; Syndrome of Marieand Guillain). This results from occlusion of theuppermost of the paramedian vessels (thalamo-perforating branches) and consists of a contra-lateral cerebellar dyssynergia and a hemianaesthesiawhich is rarely severe. Pain and temperaturesensations are often least affected but spontaneouspain does not occur. Choreoathetotic movementsmay be present.

(b) Hemiballismus. There is no doubt that themajority of cases of hemiballismus result fromhaemorrhages into the region of the subthalamicnucleus but some cases indisputably the result ofthrombosis have been reported (Meyers et al.,1950). The condition affects the contralateralbody half, and the patient-often on waking-findshis limbs on one or other side making wild, un-controllable movements. In cases due to vascularocclusion, improvement and even cessation of themovements may occur (Moniz, 193i). Otherwiseexhaustion follows and is often fatal.

(c) Rubro-ocular syndrome (inferior syndromeof the red nucleus; Syndrome of Claude orNothnagel). A third nerve palsy is present on theside of the lesion and is accompanied by a contra-lateral cerebellar dyssynergia.

(d) Benedikt's syndrome. This, too, is said toresult from involvement of the red nucleus. Anipsilateral third nerve palsy is accompanied by acoarse choreiform tremor of the opposite limbs.

(e) Weber's syndrome. An ipsilateral thirdnerve palsy is accompanied by a contralateralhemiplegia. The third nerve is affected as itpasses through the tegmentum a short distancebefore its emergence from the medial aspect ofthe cerebral peduncle.

(f) Anterior internuclear ophthalmoplegia. Ithas been claimed that the presence of an inter-nuclear ophthalmoplegia .is diagnostic of dis-seminated sclerosis, but in fact this feature can

also result from vascular, neoplastic and otherlesions. A case due to a brain stem thrombosishas been seen personally. An anterior inter-nuclear ophthalmoplegia results from a lesion ofthe medial longitudinal bundle in the neighbour-hood of the third nerve nucleus. The ocular axesremain parallel in the neutral position but onlooking to the side away from the lesion, theipsilateral eye either fails to turn medially orhaving done so slowly sways back to the midposition. The contralateral eye often shows acoarse ' ataxic nystagmus.' On looking to the sideof the lesion similar phenomena may occur thoughto a lesser degree (Cogan et al., i950).

Although described as clear-cut entities, thesesyndromes may occur in varying combinations.

The geniculate artery. Occlusion of the genicu-late artery gives rise to a contralateral ' thalamicsyndrome' and is indeed the most common causeof this condition. As a rule it occurs in isolation,but there may also be a contralateral field defect,usually a superior quadrantic hemianopia, due toinvolvement of the lateral geniculate body.

Isolated lesions of the cortical branches. Totalocclusion of the calcarine artery will give rise to anisolated contralateral homonymous hemianopia.Not uncommonly, subdivisions of this branch areaffected and homonymous quadrantic field defectsresult. These may involve the superior or inferiorquadrants but the former is the more common.

Involvement of the temporal and parieto-occipital branches to the major hemisphere maygive rise to the various dysphasic, agnostic andbody scheme disturbances already described.Occlusion of these vessels on the side of the minorhemisphere may result in visual inattention to theopposite half field. Isolated objects are perceivedin any part of the field, but when two objects areexposed simultaneously, one in each half field, onlythat on the normal side is appreciated.

(See Foix and Hillemand, I925b.)(To be concluded in the AIarch issue)

Why not have your 1952 Journals bound up into avolume NOW? See advertisement on page X,

at back of this Journal, for details.



j.bmj.com

/P


j.29.328.65 on 1 February 1953. D

ownloaded from

http://pmj.bmj.com/

the syndromes of the arteries the brain and spinal...

Documents