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65 Postgrad Med J: first published as 10.1136/pgmj.29.328.65 on 1 February 1953. Downloaded from

THE SYNDROMES OF THE OF THE AND 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

Introduction general circulatory efficiency at the time of the Little interest is shown at present in the syn- catastrophe is of the greatest importance. An dromes of the arteries of the brain and spinal cord, occlusion, producing little effect in the presence of and this perhaps is related to the tendency to a normal blood pressure, may cause widespread minimize the importance of cerebral localization. pathological changes if hypotension co-exists. Yet these syndromes are far from being fully A marked discrepancy has been noted between elucidated and understood. It must be admitted the effects of ligation and of spontaneous throm- that in many cases precise localization is often of bosis of an . The former seldom produces little more than academic interest and ill effects whilst the latter frequently determines

provides Protected by copyright. nothing but a measure of personal satisfaction to . This is probably due to the tendency the physician. But it is worth recalling that the of a spontaneous thrombus to extend along the detailed study of the distribution of the bronchi affected vessel, sealing its branches and blocking and of the pathological anatomy of congenital its collateral circulation, and to the fact that the abnormalities of the heart, was similarly neglected arterial disease is so often generalized. until the prospect of therapeutic application In this paper the various syndromes resulting demonstrated the fallacy of this attitude. from occlusion of the arteries of the brain and Cerebral thromboses are usually the expression spinal cord will be described in the light of our of diffuse vascular disease and often it is neither present knowledge. The pathology of the occlusive possible nor profitable to implicate named vessels. process will not be considered, nor will the Optimistic conclusions have often been expressed slowly developing syndromes due to diffuse in the past regarding the specific effects ofocclusion be discussed. The of one particular vessel, but are difficult to accept anatomy and distribution of the vessel in question in view of the ultimate demonstration of will be outlined briefly before its syndromes are multiple http://pmj.bmj.com/ lesions. Cases of cerebral embolism would seem described. to provide a better prospect of accurate study but are less common; many vessels are seldom, if ever, involved and the opportunity of making The internal carotid artery enters the skull pathological studies becomes very remote when through the carotid canal and runs forwards the smaller-and in many respects more interesting through the cavernous sinus to the medial aspect -vessels are affected. Cerebral angiography may of the anterior clinoid process. Here it turns in the future offer an alternative to post-mortem upwards and at the commencement of the Sylvian on September 26, 2021 by guest. examination and provide a chance of identifying fissure divides into its terminal branches-the the site of the primary occlusion at a time when the anterior and middle cerebral arteries. clinical picture remains uncomplicated. Such The results of occlusion of the internal carotid studies as that made by Ethelberg (I95I) of the artery are extremely varied. The condition is a anterior cerebral artery, are likely to lead to a chance finding at arteriography in a number of rapid expansion of our knowledge of these syn- patients who have none of the anticipated symp- dromes. toms or signs. Certainly surgical ligation of the The varied effects of occlusion of any particular vessel-if proper precautions are taken-rarely artery in different individuals depends on several gives rise to any disability. factors. The extent of the territory supplied and When symptoms do occur, the onset is often the efficacy of the collateral circulation differ gradual. Persistent of a migrainous widely from person to person. The degree of character on the same side as the thrombosis may 66 POSTGRADUATE MEDICAL JOURNAL February I953 Postgrad Med J: first published as 10.1136/pgmj.29.328.65 on 1 February 1953. Downloaded from occur for years before other features develop. third of the , the outermost part of the Transient attacks of focal weakness, of focal and the anterior limb of the internal paraesthesiae or of dysphasia are common and capsule. rarely generalized convulsions may occur. The (b) Anterior communicating artery-which often suggestion has been made that these transient gives off a few twigs to the optic chiasma and in- disturbances result from spasm of the smaller fundibular region (Rubenstein, I944). cerebral vessels reflexly induced by impulses from (c) Branches from the convexity: (i) Prefrontal nerve endings in the wall of the diseased internal or orbital branch supplying the medial aspect of carotid artery. In other cases an acute onset is the . (ii) Frontopolar branch-to the seen. The left internal carotid is affected much most anterior portion of the superior frontal more frequently than the right. gyrus. (iii) Calloso-marginal artery which divides The full syndrome that might be expected on into anterior, middle and posterior internal anatomical grounds is seen only occasionally. frontal branches supplying the medial portion of Ipsilateral anosmia is sometimes present. There 'the convexity of the frontal lobe. (iv) Paracentral is blindness of the ipsilateral eye--which may be artery-to the paracentral lobule. (v) Superior transient-due to involvement of the ophthalmic parietal branch. (vi) Precuneal branch-to the artery, while the opposite eye shows a temporal *region of the quadrate lobule. (vii) Parieto- field defect due to a lesion of the and occipital branch. radiation, Optic atrophy develops in the blind eye. (d) Branches from the concavity: (i) Numerous A severe contralateral hemiplegia and hemi- twigs to the corpus callosum and to the anterior anaesthesia are also present, together with a severe pillars of the fornix. (ii) Pericallosal artery which dysphasia if the major hemisphere is affected. lies deep to the anterior cerebral artery and con- Although mental changes of the organic reaction tinues the line of this vessel. have been attributed to occlusion of the inter- both anterior cerebral arteries arise type Occasionally Protected by copyright. nal carotid artery, their occurrence is so haphazard from the same internal carotid and sometimes only as to suggest that their presence is coincidental. one vessel is present. Cases of lesser severity are far more numerous. The most common picture is that of a moderately Occlusion of the Main Trunk Proximal to Heubner's severe hemiplegia accompanied by a hemi- Artery anaesthesia of lesser severity with Much depends on the size of the anterior com- and some degree of dysphasia. It is obvious that municating artery. If this is large and not there may be nothing characteristic about the obstructed by the thrombus, occlusion of the condition and its differentiation, particularly from main trunk of the anterior cerebral artery will occlusion of the or one of either produce no ill effects or give rise to a syn- its branches, can only be made by carotid arterio- drome similar to that following thrombosis of graphy. Heubner's artery. If the collateral circulation is (See Elvidge and Werner, 195i; Fisher, I95I.) inadequate the resulting syndrome is much more is lost. serious. In most cases http://pmj.bmj.com/ The Anterior Cerebral Artery Dandy (I930) as the result of some unfortunate From its origin at the medial end of the Sylvian experiences following the tying of the left anterior fissure, the anterior cerebral artery runs forwards cerebral artery, maintained that total occlusion of and medially across the anterior perforated sub- this vessel always resulted in stupor or coma from stance and above the optic nerve to the margin which recovery did not occur. Many cases have between the medial and orbital surfaces of the since been recorded in which ligation produced no frontal lobe. At this point the vessels of either ill effects (Poppen, I939). Major convulsions may side are connected by the anterior communicating occur and the eyes and head may be turned to on September 26, 2021 by guest. artery. Each then turns abruptly upwards to the side of the lesion due to the unbalanced action reach the genu of the corpus callosum and runs of the opposite frontal eye field (area 8). When backwards in the depths of the longitudinal fissure, the patient is conscious it may also be found that he finally emerging from it to end in the quadrate has some defect of lateral conjugate movement of lobe or the parieto-occipital fissure. Branches: his eyes to the opposite side because of the damage (a) Basal: (i) Several fine branches enter the to the ipsilateral eye field. These features are anterior perforated substance and supply the head short-lived and disappear in a few days or weeks. of the . (ii) Recurrent artery Mental changes--including all the organic re- (artery of Heubner). This pierces the lateral ex-. action types-may occur and are regarded by some tremity of the anterior perforated substance and authors as a specific part of the clinical picture, but passes upwards and outwards to supply the this cannot be maintained. Patients showing these anterior part of the caudate nucleus, the anterior conditions are usually old and have diffuse February 1953 KILOH: The Syndromes of the Arteries of the Brain and Spinal Cord 67 Postgrad Med J: first published as 10.1136/pgmj.29.328.65 on 1 February 1953. Downloaded from v Para centraL CaZZosomargtnal Peric'losalPrrerSip.Parietlsletonitrl ~ ''

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AnteriorPoterior cerebral /..Postenor/." tempoa \ ·alro . . · / . ',, Protected by copyright. Posor cre AneriorAn~i" emprdepor C C~l~r'iree FIG. I.-Medial aspect of right cerebral hemisphere showing distribution of cortical branches of anterior, middle and posterior cerebral arteries. (The paracentral branch in this case comes off the calloso-marginal artery.) (de Jong, 1950, ' The Neurologic Examination,' Cassel & Co., London.)

cerebrovascular disease. Of Ethelberg's 2o cases, common initially but rarely persists for more than seven only showed some disturbance and a few weeks. Ethelberg (I95I) maintains that the shallowness of affect. Bilateral occlusion of the speech disturbance is not a true dysphasia but an anterior cerebral arteries is of course much more 'impairment of rapid sequential movements of likely to be associated with -usually the speech organs' and is therefore a cortically accompanied by a placid euphoria-but diffuse determined . In these cases a dyspraxia http://pmj.bmj.com/ arterial disease is invariably present too. -usually ideomotor in type-is found on the side A severe hemiplegia results from the combined opposite to the paralysis. Theoretically, the effects of lesions of the anterior limb of the internal dyspraxia is bilateral but on the hemiplegic side capsule and of the paracentral lobule. The face is masked by the paralysis.' It is supposedly due to and limbs are involved more or less in equal infarction of the anterior portion of the corpus degree, though either limb may be differentially callosum which interrupts the commisural fibres

affected in some cases. After the initial period of linking the premotor and motor areas of the major on September 26, 2021 by guest. 'shock' the hemiplegia becomes spastic. Vaso- to the minor hemisphere. This portion of the motor and trophic changes are commonly marked. corpus callosum has, however, been divided sur- The skin is cold and blue and chronic oedema may gically on many occasions without producing be present. Dystrophic changes in the skin, nails, dyspraxia, and it was pointed out by Akelaitis et subcutaneous tissues and joints may follow. al. (I942) that this condition occurred only if the Sensory loss of a cortical type is present in the medial aspect of the dominant frontal lobe was also lower limb due to the lesion of the paracentral damaged. Ethelberg, though not denying the lobule and is most marked distally. Occasionally existence of a true ideomotor dyspraxia, pointed similar loss is present in the arm. Some urgency out that in his patientis the disability was simply or frequency of micturition is common. a clumsiness, particularly when performing rapid When the major hemisphere is affected, some and complex movements. He felt therefore that it degree of dysphasia of an expressive type is should be regarded as an ' impairment of rapid 68 POSTGRADUATE MEDICAL JOURNAL' February 1953Postgrad Med J: first published as 10.1136/pgmj.29.328.65 on 1 February 1953. Downloaded from sequential movements.' This particular descrip- the lower limbs occurs, together with cortical tion, however, would appear remarkably close to sensory loss. As a result of the latter there may be Liepmann's 'limb kinetic apraxia.' The dis- considerable sensory which is aggravated by turbance is transient as a rule for the minor eye closure or darkness. Precipitancy and fre- hemisphere becomes accommodated. quency of micturition are marked. A lesion of the spinal cord is therefore simulated but in most cases Occlusion of the Main Trunk beyond Heubner's the onset is episodic, first one side then the other Artery being affected. Many, too, will show varying Loss of conscipusness is less frequent than with degrees of organic deterioration. If the area of obstruction at the commencement of the artery. infarction is extensive enough to involve the corti- The contralateral paresis is highly characteristic cobulbar fibres or their cells of origin, pseudo- and affects predominantly or exclusively the lower bulbar phenomena result, causing difficulty in limb. When the upper limb is affected the weak- differentiation from a brain stem lesion. ness is most evident around the shoulder and in the upper arm-a state designated as a ' dis- Occlusion of Heubner's Artery sociated hemiplegia' by Dimitri and Victoria Occlusion of Heubner's artery gives rise to (I936)-differing from the usual type ofhemiplegia weakness of the contralateral face and upper limb. in which the weakness is maximal peripherally. In Transient weakness of the tongue and palate may addition, the hemiplegia usually remains flaccid be seen. In the upper limbs the weakness is some- with diminished or absent deep . The times more marked proximally. Some or reason for this is unknown, but it has been hyperkinesis of the affected arm may occur but suggested that it is because the deeper structures, there is doubt as to whether this is due to in- including the , are unaffected. volvement of the frontopontine tract or of the basal Fulton's made in another ganglia. A moderate degree of expressive dys-

suggestion, context, Protected by copyright. that a hemiplegia due to a lesion of area 4 is phasia is present if the lesion affects the major flaccid and becomes spastic only when area 6 is hemisphere. Apraxia and sensory loss do not also affected, scarcely seems applicable here for the occur. anterior cerebral artery supplies equivalent parts Paracentral Artery of both these areas. Occlusion of the paracentral artery gives rise to Sensory loss of a cortical variety is present in weakness of the lower limb which is usually severe the contralateral lower limb and is more marked and more marked distally. Slight weakness of distally. A sensory ataxia of this limb results the upper limb and even of the face may occasion- and may be disabling. ally co-exist. The monoplegia may be flaccid or Sometimes the upper limb though showing spastic and as a rule is accompanied by sensory little or no paralysis may be clumsy and the signs loss ofthe cortical type. Trophic changes are often of a 'cerebellar '- dyssynergia may be demon- marked. Neither nor a strable. These are slight or moderate in degree dysphasia grasp and are attributed to to the fronto- occurs. damage Occlusion of other branches of the anteriorhttp://pmj.bmj.com/ pontine tract. cerebral artery and of the main stem of the vessel at A grasp reflex, sometimes with forced groping, various points has been found post-mortem in a may be found on the same side as the hemiplegia number of cases. In life, however, there was but only when-the weakness of the upper limb is nothing characteristic in the clinical pictures to relatively slight. An increased Mayer's reflex is differentiate them from occlusion elsewhere in the also present in the affected hand (Hyland, I933). distribution of this artery. A hemiplegia with Such a finding is of localizing value. Of less crural dominance of sudden onset is always highly significance is the presence of a bilateral grasp suggestive of occlusion of some part of the anterior on September 26, 2021 by guest. reflex, often with a sucking reflex on stimulation of cerebral system. The only other vascular lesion the lips. Such cases often show catatonic features which has a similar result is thrombosis of the and one of Baldy's patients (1927) also had Rolandic vein. echolalia and palilalia. These features probably Foix and occur only with widespread disturbance of (See Critchley, 1930; Hillemand, cerebral function. 1925a.) A transient expressive dysphasia and dyspraxia Middle Cerebral Artery (Sylvian Artery) may appear when the lesion involves the dominant The middle cerebral artery is the largest branch hemisphere. of the internal carotid artery and arises at the If both anterior cerebral vessels become occluded commencement of the Sylvian fissure in which it (or if their function is subserved by a single runs. Branches: vessel which is thrombosed) bilateral paralysis of Perforating or central vessels. These are given February 1953 KILOH: The Syndromes of the Arteries of the Brain and Spinal Cord 69 Postgrad Med J: first published as 10.1136/pgmj.29.328.65 on 1 February 1953. Downloaded from .. '~Roltantc,. 'An'eriorpai'da ?terwrparire(di ·and"'..· . '. .t Pre-~olan.iC r "Y'.

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FIG. 2.-Lateral aspect of left cerebral hemisphere showing distribution of the cortical branches of the anterior, middle and posterior cerebral arteries. (de Jong, 1950, ' The Neurologic Examination,' Cassel & Co., London). off at right angles to the main vessel and penetrate Posterior parietal artery-to the posterior por- the anterior perforated substance. They are said tion of the and the supramarginal not to anastomose with one another. They vary gyrus. in number and are arranged in two sets-the Artery of the angular gyrus-continues the line medial striate and lateral striate groups. Together of the main vessel and supplies the angular gyrus these supply the lentiform nucleus, the caudate and the adjacent parietal cortex. nucleus, the posterior portion of the anterior limb, Posterior temporal artery-to the posterior two- the genu and the anterior third of the posterior thirds of the lateral surface of the lobe.

temporal http://pmj.bmj.com/ limb of the . The 'artery of These vessels form anastomoses with branches cerebral haemorrhage' so much emphasized by of the anterior and posterior cerebral arteries. Charcot, is a member of the lateral striate group There is no doubt that occlusion in the territory and is sometimes termed the lenticulo-striate of the middle cerebral artery may occur without artery. producing symptoms or signs. In other cases Cortical branches. The following vessels may transient headache, giddiness, confusion and focal be distinguished, though two or more frequently signs result but disappear rapidly and leave no arise from the main vessel by a common stem:- sequelae. In a number of cases focal or generalized on September 26, 2021 by guest. Anterior temporal artery-supplies the anterior fits are seen at the onset. third of the superior and middle temporal gyri and Occlusion -of the Main Stem of the Middle Cerebral the insula. Artery Orbitofrontal artery-supplies the inferomedial Occlusion of the first part of the middle cerebral and inferolateral aspects of the frontal lobe. artery results in profound coma which frequently Prerolandic artery-to the lower part of the pre- proves terminal. The thrombosis may commence central gyrus and adjacent frontal cortex. in one of its branches and extend back to the main Rolandic artery--to the precentral and post- artery, so that progression of symptoms occurs central gyri. over a period of hours or days. When adequate Anterior parietal artery-to the postcentral examination is possible, a severe contralateral total gyrus and the adjacent parietal cortex. hemiplegia quickly becoming spastic, a hemi- 70 POSTGRADUATE MEDICAL JOURNAL February 1953Postgrad Med J: first published as 10.1136/pgmj.29.328.65 on 1 February 1953. Downloaded from anaesthesia and a homonymous hemianopia can be features. It is commonly severe and enduring. A demonstrated. If the major hemisphere is affected severe irreversible dysphasia resulting from vascu- a severe global is also present. lar occlusion is always highly suggestive of a lesion Anosognosia, in which the paralyzed body half of the middle cerebral artery. The extent of is ignored and even disowned, is often to be recovery depends not only on the severity of the observed during the period of recovering con- damage but on the degree of dominance of the sciousness when the minor hemisphere is the site major hemisphere and on the age of the patient. A of the lesion. lesion occuring before the age of five years seldom In survivors the residual disability is severe and leads to a permanent dysphasia. contractures develop. Some retrogression of the Occasionally if the paresis is slight, dyspractic sensory loss may occur. phenomena of an ideomotor type can be detected but are short-lived. Perforating Branches Posterior group. The most striking feature due The medial and lateral striate vessels are to occlusion of the posterior group of vessels is a probably more subject to occlusion than any of contralateral homonymous hemianopia. The field the other cerebral arteries. Consciousness is defect may at times be limited to the inferior usually retained. A contralateral spastic hemi- quadrants. It is the result of a lesion of the optic plegia is constant, the weakness being equal in the radiation, for the superficial branches supply the two limbs or occasionally more obvious in the leg. subcortical white matter to a varying depth as well The severity of the hemiplegia varies widely from as the cortex itself. When the major hemisphere case to case. Disturbances of sensation in the is affected the hemianopia is accompanied by a affected body half are occasionally present but bilateral ideomotor or ideational dyspraxia. The are seldom severe. A hemianopia due to in- various disturbances of the body scheme discussed farction of the optic radiation at its commence- below under ' posterior parietal artery' are alsoProtected by copyright. ment is rare and is, in fact, more commonly the likely to be present. result of occlusion of the superficial branches of If the anterior parietal branch is also affected, the middle cerebral artery. When the major a contralateral hemiplegia of moderate degree- hemisphere is affected, a dysphasia-expressive or again due to involvement of subcortical white less frequently global in type-is often found and matter-and some cortical sensory loss over the is attributed to oedema of the overlying con- contralateral body half are also present. volutions (Davison et al., 1933). In most cases It may be very difficult to distinguish between considerable recovery of speech function ensues. the effects of occlusion of the superficial and deep Bilateral occlusion of the perforating branches branches of the middle cerebral artery. In the of the middle cerebral artery is the commonest former the weakness is likely to be greater in the cause of pseudobulbar palsy. upper limb; particularly if it commences in the upper limb and spreads to the lower, a cortical Superficial Branches origin is likely. If the hemiplegia remains per-

Isolated occlusion of the individual superficial sistently flaccid the occlusion is almost certainlyhttp://pmj.bmj.com/ branches of the middle cerebral artery is relatively superficial. Marked sensory changes and the uncommon and it is more usual to find two or presence of a field defect also favour a superficial more affected, as might be expected from their occlusion. collective mode of origin. To some-the anterior The results of occlusion of the individual super- temporal artery for example-no syndrome can ficial branches of the middle cerebral artery will as yet be ascribed. The majority of these cases now be discussed, but it must be emphasized that fall into one of two groups, those with involvement some ofthe descriptions are based on rather meagre of the more anteriorly placed branches and those details. on September 26, 2021 by guest. with involvement of the posterior branches. It is Orbitofrontal artery. On the major side an ex- often unprofitable to attempt to analyze these pressive dysphasia without paresis may follow cases further. occlusion of this branch. Occasionally weakness Anterior group. Occlusion of the anterior group of the opposite face and tongue may be demon- of vessels gives rise to a contralateral hemiplegia strable but this is apparent only, and is, in fact, affecting particularly the face and upper limb, the dyspractic in nature. Such a patient may be weakness in the latter being most marked distally. unable to protrude his tongue or whistle to order. Frequently the hemiplegia remains flaccid. Some If the lesion affects the minor hemisphere no cortical sensory loss with astereognosis is also localizing signs result. present in the upper limb. If the major hemi- Prerolandic artery. Occlusion of this vessel gives sphere is involved, a dysphasia occurs which is rise to contralateral weakness of'the lower face and usually expressive in type but may show mixed tongue. The limbs as a rule are spared completely February x953 KILOH: The Syndromes of the Arteries of the'Brain and Spinal Cord Postgrad Med J: first published as 10.1136/pgmj.29.328.65 on 1 February 1953. Downloaded from

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FIG. 3.-The arteries at the base of the brain. AC Anterior cerebral artery. pca Posterior communicating artery. aca Anterior chorioidal artery. sba Basal branches of anterior cerebral artery. a cl. p Anterior clinoid process. sbm Perforating branches of middle cerebral acm Anterior communicating artery. artery. B Basilar artery. SC Superior cerebellar artery. IC Internal carotid artery. VA . http://pmj.bmj.com/ MC Middle cerebral artery. (After Buchanan, I948, 'Functional Neuro- PC Posterior cerebral artery. anatomy,' Henry Kimpton, London.)

but weakness limited to the hand may sometimes It is accompanied by astereognosis and a sensory be seen. An expressive dysphasia, varying greatly ataxia. Pseudoathetotic movements sometimes

in intensity from case to case, is also present when occur in the affected limb when the eyes are closed. on September 26, 2021 by guest. the major hemisphere is affected. Signs of a slight pyramidal tract disturbance and Rolandic artery. Lesions due to isolated a mild degree of dysphasia may be present. occlusion of this artery are rare because of the Posterior parietal artery and the artery of the richness of the collateral irrigation of its territory. angular gyrus. Occlusion of these vessels on either Paresis of the contralateral upper limb-and to a side may give rise to a contralateral homonymous lesser extent of the face-develops, together with or inferior quadrantic hemianopia. Disturbances some degree of cortical sensory loss in the same of the body scheme are found, particularly when distribution. A slight expressive dysphasia occurs the major hemisphere is affected. The precise with lesions of the major hemisphere. form of the disturbance varies greatly from patient Anterior parietal artery. Cortical sensory loss to patient but the. most common finding is a in the contralateral upper limb and face is the most Gerstmann's syndrome comprising dysgraphia, striking feature following occlusion of this branch. dyscalculia, finger and confusion of 72 POSTGRADUATE MEDICAL JOURNAL February I953Postgrad Med J: first published as 10.1136/pgmj.29.328.65 on 1 February 1953. Downloaded from laterality (right-left disorientation). These phe- artery. Branches are given off to the optic chiasma, nomena may occur independently of one another. the tuber cinereum, the medial aspect of the Other agnostic features may be present-a visual , the anterior portion of the posterior agnosia or an agnosia for colours-and the autoto- limb of the internal capsule and the rostral third pagnosia, of which the finger agnosia is an ex- of the pes pedunculi. pression, may be more profound so that the The syndromes resulting from occlusion of this patient is unable to recognize any part of his body vessel have not been defined. Brock (1937) has (Nielson, 1946). A bilateral ideational or ideo- reported that a contralateral mimetic palsy of the motor dyspraxia is also frequently present. A face may result. dysphasia, predominantly receptive in character, The anterior lobe of the pituitary is supplied usually occurs and a dyslexia is its most prominent principally by the superior hypophyseal vessels feature. which arise directly from the internal carotid (See Foix and Levy, 1927; Tichy, I949.) arteries. Some twigs of supply come from the posterior communicating arteries. Occlusion of The Anterior Chorioidal Artery these vessels may give rise to Simmond's disease. The anterior chorioidal artery arises from the internal carotid artery near its termination. It Posterior Cerebral Artery runs backwards in close relationship with the optic Each posterior cerebral artery winds backwards tract between the uncus and the cerebral peduncle round the cerebral peduncle and passes deep to to the lower end of the chorioidal fissure. It the splenium of the corpus callosum to reach the supplies the uncus and the optic tract, the middle medial border of the inferior surface of the tem- third of the cerebral peduncle, most of the globus poral lobe where it divides into terminal or cor- pallidus, the posterior two-thirds of the inferior tical branches. Developmentally, the posterior with the half of the posterior limb of the internal capsule, cerebral artery beyond its junction Protected by copyright. the anterior half of the , the posterior communicating artery is derived from the and the lateral aspect of the external internal carotid artery (Williams, 1936). geniculate body. Branches: Paramedian group (retromamillary Proven examples of occlusion of the anterior branches). There are about Iz of these. The chorioidal artery are few. Loss of consciousness is anteriorvessels-the thalamo-perforating or medial unusual. A contralateral hemiplegia is constant ganglionic branches-enter the posterior perforated and either affects the entire body half equally or substance and terminate inthe medial portion of the the lower limb predominantly. In the former case thalamus; they also supply the mamillary body. it is probable that the lesion of the cerebral The posterior vessels-peduncular branches- peduncle is pre-eminent whilst in the latter, supply the cerebral peduncle, the substantia nigra, damage to the internal capsule is mainly re- the third nerve nucleus and the posterior half of the sponsible. Contralateral impairment of all forms subthalamic nucleus. There is little anastomosis of sensation and a homonymous hemianopia are between the vessels of the two sides.

also present. When the hemianopia is complete it Quadrigeminal artery. This is a small vesselhttp://pmj.bmj.com/ is said that the lesion responsible affects the in- which winds round the and supplies its ternal capsule, while if it be a superior quadrantic lateral aspect and the superior and inferior defect, infarction of the lateral geniculate body is colliculi. indicated (Abbie, 1933). Although considerable Posterior chorioidal artery. This vessel winds destruction of the caudate nucleus may occur, this round the midbrain and after running over the produces no characteristic signs. superior aspect of the thalamus, ends in the The combination of a hemiplegia, hemi- chorioid plexus of the third ventricle. Six or anaesthesia and hemianopia also occurs following seven branches are given off to the cerebral on September 26, 2021 by guest. occlusion of the trunk of the middle cerebral peduncle and other twigs supply the superior artery or a haemorrhage into the internal capsule. colliculus and the internal and external geniculate In such cases the result is far more grave. Deep bodies. coma will be present and the hemiplegia is very Geniculate arteries (thalamogeniculate arteries". much more severe than that following occlusion of These penetrate the external geniculate body, the anterior chorioidal artery. supplying it and the superior colliculus before (See also Steegman and Roberts, 1935.) entering the thalamus. The territory of supply includes the posterior half of the thalamus and Posterior Communicating Artery the posterior portion of the posterior limb of the This vessel arises from the internal carotid internal capsule. artery a short distance before its termination and Cortical branches: Anterior temporal, posterior passes backwards to join the posterior cerebral temporal, calcarine and parieto-occipital. February 1953 KILOH: The Syndromes of the Arteries of the Brain and Spinal Cord 73 Postgrad Med J: first published as 10.1136/pgmj.29.328.65 on 1 February 1953. Downloaded from As might be expected from its distribution, The extremities on the affected side often there are many syndromes associated with lesions become oedematous and cyanosed while trophic of the posterior cerebral artery and its branches. changes may develop in the finger nails. These When there is infarction of the cerebral hemi- changes, though associated with the hyperpathia, sphere, focal.or generalized convulsions may occur are not necessarily of equivalent intensity. at the onset and sometimes recur. Visual aurae Because of the impaired joint the affected are common. limbs show a sensory ataxia and astereognosis. The ataxia is accentuated if the superior cerebellar Occlusion of the Main Trunk of the Posterior peduncle is damaged and contralateral cerebellar Cerebral Arteryv signs may be demonstrable. The results of occlusion of the main stem of the Various features due to destruction of extra- posterior cerebral artery depend largely on the pyramidal structures or their connections- adequacy of the posterior communicating artery. notably the substantia nigra, the red nucleus and ANo ill effects may follow i f this latter vessel pro- the subthalamic nucleus-are frequently present. vides an adequate collateral circulation. When The limbs may show a plastic rigidity and the arm infarction does occur, consciousness is usually re- is held flexed at the elbow and a little flexed at the tained though occasionally persistent somnolent wrist, with fingers extended or hyperextended states result (Bacaloglu et al., I934) possibly due (thalamic hand). When walking, the arm may be to damage to the reticular substance in the teg- held extended and internally rotated with the hand mentum of the midbrain. A contralateral hemi- behind the back. Movements of a choreic or plegia is present but is moderate in degree. It is athetoid nature may be present and are accentuated due to infarction of the cerebral peduncle. The by emotion and often by voluntary movements of most important and characteristic finding is a the normal limb. In the latter case mirror move- contralateral ' thalamic '-first des- ments be seen. Tremor occurs syndrome may rarely Protected by copyright. cribed by Dejerine and Egger (I903) and again (Langworthy and Fox, 1937). with pathological studies by Dejerine and Roussy Other signs may result from midbrain damage. (I906). Paroxysmal or constant is present An ipsilateral third nerve palsy or a defect of in the affected body half including the face. As a superior conjugate ocular movement (Parinaud's rule it is severe and often has a burning quality. syndrome) sometimes occurs. An ipsilateral It usually occurs spontaneously but may be pro- Horner's syndrome is more common than either. voked by heat, cold, movement or deep pressure. Lastly, there may be evidence of damage to the Pricking or icy cold sensations may be experienced. occipital and posterior parietal and temporal areas Although commonly diffuse, the pain may some- of cortex. A contralateral homonymous hemi- times be sufficiently localized to simulate abdominal anopia which is usually complete occurs but disease. Rectal or vesical pain associated with sometimes there is apparent sparing ofthe maculae. tenesmus or strangury is not uncommon. There is no evidence to support the suggestion that The objective sensory findings vary from case the maculae are represented bilaterally, nor is the to and in case, general their Severity is inversely view tenable that the macular areas are supplied by http://pmj.bmj.com/ proportional to the amount of pain. Typically bythe middle cerebral arteries. It is more probable there is impairment of the sense of passive move- that so-called macular sparing is an artefact due to ment, of deep sensation and vibration sense. Pain, shifting fixation by the patient. touch and temperature sensations on casual If the lesion affects the major hemisphere a examination appear to be unaffected and the dysphasia is also present. In general this is re- occurrence of hyperaesthesia or hyperpathia may ceptive in type but it is rarely severe. Often even suggest an increased sensitivity. More care- reading is particularly affected so that the defect

ful examination reveals that the threshold value of approaches closely to a . Visual on September 26, 2021 by guest. the stimulus is raised and its localization is poor. agnosia may also be present and very occasionally Sometimes the response to pleasurable stimuli is there is visual autotopagnosia, which is more often also exaggerated and such things as music which partial than complete. produce a general affective tone may evoke a re- The paramedian branches. Corresponding to the action on the altered side so intensely pleasurable short circumferential branches at lower levels are as to be unbearable. One of Head's patients twigs given off to the lateral aspect of the midbrain became somewhat amorous after his ictus and re- by the various branches of the posterior cerebral marked that his affected side had become more artery. They are not so clearly defined as the responsive and more desirous of solace. The corresponding vessels in the lower brain stem and essential lesion was shown by Roussy to affect the as yet it is not possible to ascribe any particular posterior third of the lateral nucleus of the syndromes to their occlusion. It is probable that thalamus. they play a part in some of the syndromes des- 74 POSTGRADUATE MEDICAL JOURNAL February '953Postgrad Med J: first published as 10.1136/pgmj.29.328.65 on 1 February 1953. Downloaded from cribed below as the result of obstruction of the also result from vascular, neoplastic and other various paramedian branches. lesions. A case due to a brain stem thrombosis (a) Rubrothalamic syndrome (superior syn- has been seen personally. An anterior inter- drome of the red nucleus; Syndrome of Marie nuclear ophthalmoplegia results from a lesion of and Guillain). This results from occlusion of the the medial longitudinal bundle in the neighbour- uppermost of the paramedian vessels (thalamo- hood of the third nerve nucleus. The ocular axes perforating branches) and consists of a contra- remain parallel in the neutral position but on lateral cerebellar dyssynergia and a hemianaesthesia looking to the side away from the lesion, the which is rarely severe. Pain and temperature ipsilateral eye either fails to turn medially or sensations are often least affected but spontaneous having done so slowly sways back to the mid pain does not occur. Choreoathetotic movements position. The contralateral eye often shows a may be present. coarse ' ataxic nystagmus.' On looking to the side (b) . There is no doubt that the of the lesion similar phenomena may occur though majority of cases of hemiballismus result from to a lesser degree (Cogan et al., i950). haemorrhages into the region of the subthalamic Although described as clear-cut entities, these nucleus but some cases indisputably the result of syndromes may occur in varying combinations. thrombosis have been reported (Meyers et al., The geniculate artery. Occlusion of the genicu- 1950). The condition affects the contralateral late artery gives rise to a contralateral ' thalamic body half, and the patient-often on waking-finds syndrome' and is indeed the most common cause his limbs on one or other side making wild, un- of this condition. As a rule it occurs in isolation, controllable movements. In cases due to vascular but there may also be a contralateral field defect, occlusion, improvement and even cessation of the usually a superior quadrantic hemianopia, due to movements may occur (Moniz, 193i). Otherwise involvement of the lateral geniculate body. exhaustion follows and is often fatal. Protected by copyright. (c) Rubro-ocular syndrome (inferior syndrome Isolated lesions of the cortical branches. Total of the red nucleus; Syndrome of Claude or occlusion of the calcarine artery will give rise to an Nothnagel). A third nerve palsy is present on the isolated contralateral homonymous hemianopia. side of the lesion and is accompanied by a contra- Not uncommonly, subdivisions of this branch are lateral cerebellar dyssynergia. affected and homonymous quadrantic field defects (d) Benedikt's syndrome. This, too, is said to result. These may involve the superior or inferior result from involvement of the red nucleus. An quadrants but the former is the more common. ipsilateral third nerve palsy is accompanied by a Involvement of the temporal and parieto- coarse choreiform tremor of the opposite limbs. occipital branches to the major hemisphere may (e) Weber's syndrome. An ipsilateral third give rise to the various dysphasic, agnostic and nerve palsy is accompanied by a contralateral body scheme disturbances already described. hemiplegia. The third nerve is affected as it Occlusion of these vessels on the side of the minor passes the a short distance hemisphere may result in visual inattention to the through opposite half field. Isolated objects are perceived before its emergence from the medial aspect of http://pmj.bmj.com/ the cerebral peduncle. in any part of the field, but when two objects are (f) Anterior internuclear ophthalmoplegia. It exposed simultaneously, one in each half field, only has been claimed that the presence of an inter- that on the normal side is appreciated. nuclear ophthalmoplegia .is diagnostic of dis- (See Foix and Hillemand, I925b.) seminated sclerosis, but in fact this feature can (To be concluded in the AIarch issue) on September 26, 2021 by guest.

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