Blood Supply

Structure #2

Middle Cerebral Artery

Structure #4

Posterior communicating artery

Structure #1

Internal Carotid artery

Structure #3

Anterior Cerebral Artery

Structure #6

Vertebral Artery

Structure #9

Basilar artery

Structure #1

Posterior Cerebral Artery

Structure #4

Anterior Inferior Cerebellar artery

Structure #6

Vertebral Artery

Structure #8

Anterior Spinal Artery

Structure #7

Posterior Inferior cerebellar artery

Structure #9

Basilar artery

Structure #5

Labyrinthine (internal auditory) artery

Structure #3

Pontine arteries

Structure #2

Superior cerebellar artery

Stroke is

5th leading cause of death & 1st leading cause of disability

Types of Stroke

Ischemic & Hemorrhagic

Ischemic stroke

most common (85%) and is BLOCKAGE in an artery

Hemorrhagic stroke

rupture of an artery (aneurysm)

Types of ischemic stroke

Embolic + Thrombotic

Infarct

area of dead cells/ necrotic tissue

ischemia

restriction in blood supply

Anoxia

without oxygen

Hypoxia

decreased oxygen

lesion

injury

Carotid endarterectomy (CEA)

A surgical procedure to remove plaque from the carotid arteries to improve blood flow and reduce stroke risk.

2 major arterial systems

Anterior circulation and Posterior circulation.

Anterior Circulation

Internal Carotid Arteries (80%) of the brain and supply most of the cerebral hemispheres

Posterior Circulation

Vertebral arteries + basilar artery (20%) of brain and supply to BS, SC, Diencephalon, etc

Structures of the ICA

8 total, Internal Carotid has 3 branches: Ophthalmic Artery, Anterior Choroidal Artery, Posterior Communicating Artery. 2 bifurcates: Anterior Cerebral Artery (ACA) with Anterior communicating artery & Middle Cerebral Artery (MCA) with lenticulostriate arteries

(ICA) Ophthalmic

Travels along with optic nerve to orbit to supply eye; when blocked causes BLINDNESS

(ICA) Anterior Choroidal Artery

Supplies several structures, fairly COMMOn site of stroke leads to deficits in functions

(ICA) Posterior Communicating Artery

Connects ICA to the posterior cerebral artery

(ICA) bifurcation Anterior Cerebral Artery (ACA)

runs medially and enters the longitudinal fissure and supplies tops + medial parts of frontal+parietal

(ICA) bifurcation Middle Cerebral Artery (MCA)

Larger than ACA, runs lateral while supplying the insula and is most common site of occlusion + stroke

(ICA) Anterior communicating artery

only ONE of these and most common site for aneurysms (20-25%) that may cause visual deficits

(ICA) Lenticulostriate Arteries

supply portions of internal capsule and basal nuclei, leads to symptoms out of proportion to the size

ACA Brain Area Affected: Primary motor cortex (medial precentral gyrus)

Contralateral hemiplegia (worse in legs)

ACA Brain Area Affected: Primary somatosensory

Contralateral hemiparatheisa (worse in legs)

ACA Brain Area Affected: Premotor area

Apraxia

ACA Brain Area Affected: Basal Nuclei

Planning and timing of movement + movement habits/patterns

ACA Brain Area Affected: Ventromedial prefrontal cortex + limbic system

Cognitive impairment + affective/personality changes

MCA Brain Area Affected: Primary motor cortex (lateral precentral gyrus)

contralateral hemiplegia (worse in arm, trunk, face)

MCA Brain Area Affected: Primary somatosensory cortex (lateral postcentral gyrus)

Contralateral somatosensory loss (worse in the arm, trunk, face)

MCA Brain Area Affected: Deep + superficial visual pathway

Visual + visual perceptual impairments

MCA Left hemisphere damage

Broca’s/Wernicke’s area (aphasia), Posterior multimodal association cortex (ideational apraxia), frontal lobe, limbic system (emotional lability, depression)

MCA Right hemisphere damage

Posterior association area (perceptual deficits), Frontal lobe (impulsive, poor judgement), Limbic system (euphoria, well-being)

Venous Drainage of Brain

Network of deep + superficial veins→ Dural sinuses→ Right & Left Internal Jugular Veins (IJVs)

Cerebral Arterial Circle (Circle of Willis)

Anastomosis connection that surrounds the optic chiasm + pituitary gland

Circle of Willis connects

Internal carotid + Vertebral-Basilar systems

Purpose of the Circle of Willis

ensure blood flow to brain when systems are compromised

“Textbook” Circle of Willis

Less than ½ population

Vertebral-Basilar System Structures

10, Vertebral Artery includes: Anterior spinla artery,Posterior spinal artery, Posterior inferior cerebellar artery (PICA), Basilar Artery includes: Anterior Inferior Cerebellar artery (AICA) Labyrinthine artery, Pontine arteries, Superior Cerebellar Artery, Basilar artery bifurcates at Posterior Cerebral Artery

Vertebral Artery (VA)

Arises from subclavian artery, ascends in transverse foramina of the cervical vertebra

(VA) Anterior Spinal Artery

1, supplies anterior 2/3 of spinal cord, damage leads to more motor systems

(VA) Posterior Spinal Artery

Supplies 1/3 posterior of spinal cord, damage leads to more sensory symptoms

(VA) Posterior Inferior Cerebellar Artery (PICA)

Supplies posterior portions of inferior cerebellum + lateral medulla, Damage to this artery results in Wallenbergs syndrome

Wallenberg’s syndrome

Damage to PICA, with dysphagia, hoarseness, vertigo + disquilibrium, nystagmus, uncontrollable hiccups

Basilar Artery (BA)

1 of these, begins inferiorly at the junction of the anterior pons + medulla, Damage leads to impaired blood flow

(BA) Anterior inferior cerebellar artery (AICA)

Supplies anterior portions of inferior cerebellum + inferior pons

(BA) Labyrinthine (internal auditory) Artery

Supplies inner ear, damage leads to vestibular symptoms and ipsilateral deafness

(BA) Pontine Arteries

smaller branches of basilar artery, supplies pons with blockage leads to Locked-In syndrome

(BA) Superior Cerebellar Artery

Branches at superior part of BA, Supplies superior cerebellum, interior midbrain, + superior pons

Cerebellar Arteries Occlusion/Hemorrhaging symptoms

incoordination, Ataxia, Intention tremors, Dizziness, Nystagmus, Balance problems, Dysphagia

Brainstem Arteries Occlusion/Hemorrhaging symptoms

Dysphagia, Nystagmus, Eye movement problems, Dizziness, Balance disorders, Coma, other CN symptoms

Posterior Cerebral Artery (PCA)

Curves around the midbrain, supplying the midbrain,, medial + inferior temporal + occipital lobes and parts of diencephalon

PCA Brain Area Affected (Occipital lobe, Temporal Lobe, Posterior association cortex)

Visual + visual-perceptual impairments

PCA Brain Area Affected (Midbrain)

SEE Above “Dysphagia, Nystagmus, Eye movement problems, Dizziness, Balance disorders, Coma, other CN symptoms”