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55 Cards in this Set
- Front
- Back
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What region of the brain is fed by the Anterior Cerebral Artery?
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Cortex on the anterior medial surface of the brain from the frontal to anterior parietal lobes (ACA follows along the corpus callosum in the interhemispheric fissure. Also feeds medial portion of sensorymotor cortex.
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What areas of the brain are fed by the superior division of the middle cerebral artery?
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cortex above the Sylvian fissure including lateral frontal lobe and peri-Rolandic cortex
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What areas are fed by the inferior division of the middle cerebral artery?
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cortex below Sylvian fissure including lateral temporal lobe and parts of parietal lobe.
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Describe the path of middle cerebral artery.
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Arises from the internal carotid arteries at the Circle of Willis. Exit Circle laterally into the Sylvian.Bifurcates into superior and inferior divisions that form loops as they pass over insula and around and over operculum. Exit Sylvian fissure at the lateralconvexity. MCA feeds most of cortex on dorsolateral convexity of brain.
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What brain regions are fed by posterior cerebral artery?
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PCA raises from the top of the basilar arteries into the Circle of Willis. Feeds inferior and medial temporal lobes and medial occipital cortex. Covers inferior and medial temporal and occipital cortex.
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Where do the lenticulostriate arteries originate. Why are they important? What regions do they feed? What disease often affects them?
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Originate from original portions of middle cerebral artery at the base of the brain before MCA enters Sylvian fissure. Supply large regions of basal ganglia and internal capsule. They are small vessels and prone to narrowing with HTN. Can lean to lacunar infarction, rupture and intracerebral hemorrhage.
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Where do the anterior choroidal arteries originate. Why are they important? What regions do they feed?
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Arise from internal carotid arteries. Feeds portions of globus pallidus, putamen, thalamus, posterior limb of internal capsule.
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What are the thalamoperforator arteries
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Small penetrating arteries arise from the posterior cerebral arteries near the basilar artery. Supply thalamus and part of posterior limb of internal capsule
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What arteries supply blood to the basal ganglia?
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ACA, MCA, anterior choroidal artery
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What artery supplies blood to thalamus?
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PCA
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What symptoms are observed with infarct to left MCA superior region?
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Right face/arm weakness of UMN type, nonfluent/Broca's aphasia. Possible right face/arm cortical-type sensory loss
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Where is the location of an infarct likely to be for a patient with fluent/Wernicke's aphasia, right visual field loss, Some right face/arm cortical-type sensory loss. Motor functioning generally intact
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Left MCA inferior division infarct
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What symptoms are present with cortical-type sensory loss?
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Extinction to bilateral sensory stimulation on affected side (contralateral to lesion), decreased stereognosis (ability to identify object by touch), graphesthesia (inabilty to identify numbers written on palm)
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What symptoms are present with a left MCA lesion in the deep territory?
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Right pure motor hemiparesis of UMN type.
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What symptoms are present with a left MCA stem infarct?
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Right hemiplegia, right hemianesthesia, right homonymous hemianopia, global aphasia, left gaze preference at onset from damage to left frontal eye fields.
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What artery is likely affected with the following symptoms? left face and arm weaness of UMN type, left hemineglect, Posible left face/arm cortical-type sensory loss.
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Right MCA superior division infarct
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What is the direction of a gaze preference after an MCA infarct?
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Toward the side of the deficit. This is bc the frontal eye field in the frontal cortex is damaged and these are the areas involved in driving the eyes to the opposite side.
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What sx are present after right MCA inferior division infarct?
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Profound left hemi-neglect, left visual field and somatosensory deficits. Motor neglect. Possible right-sided gaze preference.
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Name symptoms of right MCA deep territory infarct
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left pure motor hemiparesis
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What sx are present with right MCA stem infarct?
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left hemiplegia, left hemianestheis, left homonymous hemianopia, profound left neglect, right gaze preference
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What artery is involved with the following sx: right leg weakness of UMN type, right lege cortical-type sensory loss, grasp reflex, frontal lobe beahvioral abnormalities, transcortical aphasia
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Left ACA infarct
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What are the sx of right ACA infarct?
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left lege weakness of UMN type, left lege cortical-type sensory loss, grasp reflex, frontal lobe behavioral abnormalites, left hemineglect
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What sx are present for left PCA infarct?
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right homonymous hemianopia, alexia without agraphia (can be present if bleed includes splenium of corpus callosum) Larger infarct could affect thalamus and internal capsule an may cause aphasi, right hemisensory loss, and right hemiparesis
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What sx are present for right PCA infarct?
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left homonymous hemianopia, if thalamus and internal capsule are involved can have left hemisensory loss and left hemiparesis
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Where are the watershed zones. What is the result of watershed infarcts?
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Watershed zones are regions between cerebral arteries and are most susceptible to infarction and ischemia. Can cause proximal arm and leg weakness (man in barrel where are weak in muscle close to trunk).
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What factors increase risk of watershed infarcts?
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Drops in SBP,sudden occlusion of internal carotid artery
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What is ischemic stroke and when does it occur?
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Occurs when there is inadequate blood supply to a region of the brain long enough to cause cell death (infarction).
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What is the difference btwn embolic and thrombotic infarcts
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Embolic infarcts occur when a piece of material (e.g., blood clot) is formed in one place and then travels through artery to a smaller area where it gets "stuck". May have sudden onset with maximal deficits at onset.
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What is a thrombotic infarct?
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Blood clot froms on vessel wall at site of atherosclerotic plaque and vessel occludes. May develop slowly.
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What syndrome would be noted with an infarct of the posterior limb of the internal capsule and what arteries would be involved?
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Pure motor hemiparesis with dysarthria. Can also have ataxia on the side as the weakness.
1. Lenticulostriate arteries, anetrior choroidal arter, perforating branches of posterior cerebral artery |
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What symptoms would be present from an infarct of the ventral pons?
Corona Radiata? Cerebral Peduncles? What arteries would be involved? |
Infarction in ventral pons, corona radiata or cerebral peduncles is likely to result in pure motor hemiparesis and dysarthria. Can also have ataxia on the same side as the weakness.
Arteries affected include: ventral penetrating arteries of basilar artery (ventral pons), small middle cerebral artery branches (corona radiata), small middle cerebral artery branches (cerebral peduncles) |
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What symptoms are present with an infarct of the thalamoperforator branches of the posterior cerebral artery feeding the ventral posterior lateral nucleus of the thalamus?
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VPL nucleus of the thalamus is involved in sensory function. Infarction in this area could lead to sensory loss to all primary modalities in the contralateral face and body. Also known as a purse sensory stroke.
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What symptoms occur with a lacunar infarct to the posterior limb of the internal capsule and either thalamic ventral posterior lateral nucleus or thalamic somatosensory radiation?
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sensorimotor symptoms: pure motor hemiparesis and thalamic lacunar sx. Vessels involved could be thalamoperforator branches of PCA, lenticulostriate arteries
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Differentiate between embolic infarcts and thrombotic infarcts
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Emobli are material that is formed in one place and dislodged to another. Often involves sudden deficits. Emboli usually cause large-vessel infarcts involving cerebral or cerebellar cortex.
Thrombotic infarcts are clot developing locally at site of atherosclerosis causing occlusion of vessel. |
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What is a lacune?
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Small vessel infarct that usually develops from HTN and affects deep matter structures and white matter tracts. Affects BG, thalamus, BS
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Where do emboli and thrombosis usually occur?
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Emboli usually cause large vessel infarcts resulting in cerebral and cerebellar cortex. Thrombosis usually occurs in large proximal vessels such as vertebral, basilar and carotid arteries and can contribute to lacunar infarction.
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What cardiac disorders increase risk of stroke?
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Atrial fibrillation, mechanical valves or valve disfunction, decreased ejection fraction, patent foramen ovale
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What purpose does a CT serve for a patient presented at ER with sx of stroke?
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CT will not show infarct close to the event, but will show hemorrhaging to help determine if there is hemorrhage as well as stroke.
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When is tissue plasminogen activator an appropriate treatment for stroke?
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When hemorrhage has been ruled out and pt is being treated within 3 hours of stroke onset. It is a thrombolytic agent that increased chances of good functional recovery but increases risk of intracranial hemorrhage.
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Name compounds used to help prevent brain tissue damage after stroke.
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Antioxidants, calcium channel blockers, gluatmate receptor antagonists. Angioplasty and steneting of stenosed vertebral, carotid and intracranial vessels are tried. Hyperglycemia must be managed as it can worsen infarctions.
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What tests are used to assess blood flow in major cranial and neck vessels?
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Dopper ultrasound, MRA magnetic resonance angiography. Electrocardiogram reveals evidcne of cardiac ischemia. Echocardiogram looks for structural abnomalities or thrombi.
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What type of stroke are pts with afib at increased risk for? How can the risk be decrease?
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Embolic stroke. Treat with coumadin
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How is edema and mass effect treated with MCA infarct?
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Hemicraniectomy-remove part of skull to decrease risk of herniation
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Which vessel is at risk with atherosclerosis?
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Stenosis of internal carotid artery just after carotid bifurcation (carotid stenosis). This can embolize leading to TIAs or infarcts of carotid brances inclduing MCA, ACA and opthalmic artery.
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What sx are often associated with carotid stenosis?
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Since this can embolize and affect MCA, ACA and opthalamic artery, often see contralateral face-arm or face-arm-leg weakness, contralateral sensory changes, contralateral visual field defects, aphasia or neglect. Can also have ipsilateral monocular visual loss. If ACA territory is affected will also have contralateral leg weakness.
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What is the difference between carotid stenosis and carotid occlusion?
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Carotid stenosis occurs when thrombi embolize distally. Carotid occlusion is when an internal carotid artery gradaully or suddenly becomes 100% occluded. Can be asymptomatic if adequate collateral flow is available via ACoa and PCoa. Occlusion usually occurs just after bifurcation and vessel becomes filled with thrombus up to ophthalamic artery. Do not attempt endarterectomy (incision in carotid artery to remove atheromatous material) b/c riks of dislodging more emboli. This surgery is more frequently conducted with symptomatic carotid stenosis with good results.
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What is the result of a sudden drop in SBP leading to a carotid stenosis?
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Canlead to infarction in the MCA-ACA watershed area.
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Where do superficial veins drain?
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Into superior saggital sinus and cavernous sinus
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Where do deep veins drain?
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Into great vein of Galen
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What vein does all venous blood eventually reach?
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Internal jugular veins
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Describe the path of venous blood in the superior saggital sinus
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Superior saggital sinus that runs along the top/dorsal surface of the cortex, moves posteriorly and runs down the back of the brain to empty into the transverse sinuses that run anteriorly along the posterior base of the brain. These sinuses turn downward and become one sigmoid sinus that exits the skull at the jugular foramen forming the internal jugular vein.
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Describe the path of venous blood in the cavernous sinus.
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Two cavernous sinuses wrap around internal carotid artery and CN III, IV, V, VI. Drains into superior petrosal sinus into transverse sinuses and into the internal jugular vein.
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Where does venous blood from internal structres drain?
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Deep structures drain into internal cerebral veins, basal veins of Rosenthal and other veins to reach great cerebral vein of Galen. This empties into dura of tentorium and is joined by inferior sagittal sinus to form the straight sinus. Straight sinus meets transverse sinus and occipital sinus and this is called confluence of sinuses or torcula.
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What is torcula?
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This is the confluence of sinuses-where transverse sinuses meet (blood from superior saggital sinus and cavernous sinus) straight sinus (blood from internal cerebral veins via great vein of Galen, and inferior saggital sinus) and occipital sinus.
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What is saggital sinus thrombosis and whom does it affect?
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Obstruction of venous drainage and can result in increased intracranial pressure. Can lead to parasaggital hemorrhages, cerebral perfusion from increased venous pressure, and infarcts. Seizures can occur. HA and papilledema are often present as well as decreased consciousness. Occurs more frequently in pregnant women and within few weeks post delivery. Can be treated with anticoagulation therapy. Seizures and increased ICP can also be treated.
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