Overview
Major regions of stroke
| Region | Area supplied | Function |
|---|---|---|
| Middle cerebral artery (MCA) | Lateral frontal lobes, temporal lobes, lateral anterior parietal lobes | Upper body and language |
| Anterior cerebral artery (ACA) | Mesial and anterior frontal lobes, medial parietal lobes | Lower body, pelvic floor musculature, and sensory integration |
| Ophthalmic artery | Eyes | Vision |
| Posterior cerebral artery (PCA) | Occipital lobes, posterior temporal lobes, posterior parietal lobes, midbrain, and various cranial nerve ganglia (III, VII, X, XII) | Vision, balance, sensory integration, and cranial nerve function |
| Posterior inferior cerebral artery (PICA | Posterior inferior cerebellum, posterior lateral medulla | Facial sensation, pain sensation from body, and CN X function |
Vascular Territories
Anterior vs Posterior Circulation
| Circulation | Description | Presentation |
|---|---|---|
| Anterior circulation | A thrombus is likely from the carotid system. It mostly affects cerebral function | Aphasia, dysphasia, hemiparesis, amaurosis fugax, hemisensory loss, and hemianopic visual loss |
| Posterior circulation | A thrombus is likely from the vertebro-basilar system. It mostly affects the cerebellar and brainstem function | Diplopia, vertigo, vomiting, dysphagia, dysarthria, hemianopic visual loss, hemisensory loss, transient global amnesia, and loss of consciousness (rare) |
Vascular territories and common presentation
| Location | Presentation |
|---|---|
| Middle cerebral artery (50%) | Facial and upper extremity weakness/numbness, aphasia (left MCA), dysarthria, dysphagia, contralateral homonymous hemianopsia, and hemineglect (right MCA) |
| Anterior cerebral artery | Lower extremity weakness/numbness, urinary incontinence, primitive reflexes, rigidity, and gait apraxia |
| Posterior cerebral artery | Prosopagnosia, macular-sparing homonymous hemianopsia, alexia, visual hallucinations, sensory loss, CN III palsy, and motor deficits |
| Internal carotid artery | Similar to MCA stroke, monocular blindness, amaurosis fugax if the ophthalmic artery is affected |
| Lacunar stroke | Pure motor or pure sensory – “clumsy hand” |
Anterior circulation stroke
| Syndrome | Motor/Sensory | Visual | Others |
|---|---|---|---|
| MCA | Upper body, facial droop | Eyes deviate towards the lesion, contralateral homonymous hemianopsia | Verbal deficits (receptive or expressive aphasia), verbal agnosia, confusion, apraxia, spatial deficits |
| ACA | Lower body, pelvic | N/A | Urinary incontinence, personality change |
Posterior circulation stroke
| Syndrome | Motor/Sensory | Visual | Others |
|---|---|---|---|
| PCA | N/A | Contralateral homonymous hemianopsia with macular sparing, visual agnosia, prosopagnosia | Visual hallucinations |
| Weber | Contralateral hemiparesis | Ipsilateral CN III palsy, Ipsilateral Horner’s syndrome | Contralateral gait disturbance (mild) |
| Benedikt | Contralateral hemiataxia (choreiform movements) | Ipsilateral CN III palsy, Ipsilateral Horner’s syndrome | Contralateral gait disturbance (severe) |
| Lateral medullary | Ipsilateral facial sensory loss, contralateral body loss of pain and temperature | Ipsilateral Horner’s syndrome | Vertigo, ataxia, dysarthria, dysphagia |
| Lacunar | Pure motor, pure sensory stroke (isolated focal signs) |
Middle Cerebral Artery (MCA) Territory Stroke
The MCA is the most common artery involved in stroke. It divides into a superior and inferior branch. An MCA territory stroke affects the upper body more than the lower body. If the stroke is on the left hemisphere it can affect language, e.g. Broca’s and Wernicke’s aphasia
- Signs and symptoms
- Contralateral lower facial paralysis
- Contralateral body hemiplegia/sensory loss
- Receptive or productive aphasia (dominant lesion)
- Neglect (non-dominant lesion)
- Verbal agnosia
- Bilateral eye deviation towards the side of infarct (affects CN III but abduction by CN VI remains intact). May have contralateral homonymous hemianopsia (rare)
Anterior Cerebral Artery (ACA) Territory Stroke
ACA territory stroke affects the lower body more than the upper body
- Signs and symptoms
- Contralateral body hemiplegia and sensory loss
- Urinary incontinence (due to weakness of pelvic floor musculature)
- Anosmia (olfactory bulb)
- Personality change (frontal lobe, long-term symptom)
- Abulia (unmotivated state)
- Amnesia
Posterior Cerebral Artery (PCA) Territory Stroke
PCA territory strokes present with visual symptoms. There are rarely motor symptoms in a true PCA stroke.
- Signs and symptoms
- Contralateral hemianopsia (primary visual cortex)
- Visual hallucinations
- Visual agnosia e.g. Prosopagnosia (difficulty recognising faces)
- Occasionally neglect (non-dominant)
- Transcortical aphasia (dominant)
- Behavioral abnormalities and confusion (thalamic)
- Signs and symptoms of midbrain lesions
- Contralateral hemiparesis
- Ipsilateral CN III palsy
- Contralateral ataxia
Basilar Territory Stroke
- Contralateral signs and symptoms
- Hemiparesis with or without UMN facial weakness
- Hemisensory
- Intranuclear ophthalmoplegia (MLF damage)
- Ipsilateral signs and symptoms
- Horizontal gaze paralysis (PPRF damage)
- Ataxia
- LMN facial weakness (CN VII nucleus damage)
- Facial sensory loss (CN V damage)
- Nystagmus
Weber and Benedikt Syndrome
Weber and Benedikt syndrome is a mid-brain stroke caused by blockage of a penetrating branch of the PCA. It affects the substantia nigra, corticopontine tract, pyramidal tract, and CN III.
| Syndrome | Structures affected |
|---|---|
| Weber syndrome | Substantia nigra, corticopontine tract, pyramidal tract, and CN III |
| Benedikt syndrome | Substantia nigra, corticopontine tract, pyramidal tract, CN III, and red nucleus |
- Signs and symptoms
- Parkinsonian like symptoms (affects substantia nigra)
- Ipsilateral oculomotor palsy (down and out eyes)
- Contralateral hemiplegia
- Gait disturbance in Benedikt syndrome due to involvement of the red nucleus
Lateral Medullary Syndrome (PICA Territory Infarct)
Lateral medullary syndrome is a stroke which affects the postero-lateral medulla due to blockage/haemorrhage of the posterior inferior cerebellar artery (PICA)
- Signs and symptoms
- Pain and temperature loss in the contralateral body and ipsilateral face
- Dysphagia (due to involvement of CN X)
- Ipsilateral Horner’s syndrome (due to infarct of descending sympathetic tract)
- Dizziness, ataxia and dysarthria
Lateral Pontine Syndrome
Lateral pontine syndrome is caused by infarction of the anterior inferior cerebellar artery. It affects the lateral spinothalamic tract, CN VII nucleus(lower motor neuron lesion), CN VIII nucleus, cerebellar peduncle, and descending sympathetic tract
- Signs and symptoms
- Pain and temperature loss in the contralateral body and ipsilateral face
- Central hearing loss due to involvement of CN VIII
- Nystagmus
- Loss of balance
- Gait ataxia
- Ipsilateral Horner’s syndrome
Anterior Inferior Cerebellar Artery (AICA) Territory Stroke
- Signs and symptoms
- ipsilateral ataxia
- Ipsilateral hearing loss (labyrinthine artery branch)
- Vertigo
Posterior Inferior Cerebellar Artery (PICA) Territory Stroke
- Contralateral signs and symptoms
- Hemi-sensory loss
- Ipsilateral signs and symptoms
- Tongue deviation
- Facial sensory loss
- Horner’s syndrome (sympathetic damage)
- Ataxia
- Bulbar signs and symptoms
- Dysarthria
- Dysphagia
- Nystagmus
- Hoarseness