CNS Mod 3 TOPIC 1 – VASCULAR SYSTEM OF THE BRAIN & CLINICAL OCclusions

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add image of circle of Willis

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add image of internal carotid artery

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add image of vertebral artery

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add image of basilar artery

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add image of middle cerebral artery (MCA)

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add image of anterior cerebral artery (ACA)

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add image of posterior cerebral artery (PCA)

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add image of anterior communicating artery (ACOM)

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add image of posterior communicating artery (PCOMM)

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add image of ophthalmic artery

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add image of superior division of MCA

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add image of inferior division of MCA

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add image of anterior spinal artery (ASA)

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add image of posterior inferior cerebellar artery (PICA)

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add image of anterior inferior cerebellar artery (AICA)

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add image of superior cerebellar artery (SCA)

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add image of pontine arteries

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add image of penetrating arteries (brainstem)

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add image of anterior circulation (red)

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add image of posterior circulation (blue)

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add image of MCA occlusion on CT/MRI

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add image of ACA occlusion on CT/MRI

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add image of PCA occlusion on CT/MRI

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add image of superficial cerebral veins

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add image of deep cerebral veins

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add image of bridging veins

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add image of dural sinuses (superior sagittal)

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add image of superior sagittal sinus

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add image of inferior sagittal sinus

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add image of straight sinus

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add image of transverse sinuses

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add image of sigmoid sinuses

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add image of confluence of sinuses

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add image of falx cerebri

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add image of tentorium cerebelli

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add image of internal jugular vein

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add image of homunculus with MCA and ACA territories

circle of Willis

Hexagonal network of vessels that gives rise to MCA ACA and PCA; fed by paired internal carotids and basilar artery; contains PCOMM and ACOMM when complete

internal carotid artery

Branch off common carotid; supplies forebrain via ACA and MCA; enters skull via carotid foramen; first branch is ophthalmic artery

vertebral artery

Arises from subclavian artery; passes through foramen magnum; joins contralateral side to form basilar artery; supplies occipital lobe thalamus brainstem and cerebellum

basilar artery

Single artery formed by union of two vertebral arteries; gives rise to PCA AICA pontine arteries and SCA

middle cerebral artery (MCA)

Supplies primary motor and somatosensory cortices for face hand and arm; bifurcates in Sylvian fissure into superior and inferior divisions; called artery of speech

anterior cerebral artery (ACA)

Supplies primary motor and somatosensory cortices for trunk leg foot and genitals; supplies medial frontal lobe including prefrontal cortex and limbic areas

posterior cerebral artery (PCA)

Supplies occipital lobe; lower temporal lobe; thalamus; choroid plexuses of 3rd and lateral ventricles; primary and secondary visual cortices

anterior communicating artery (ACOM)

Connects left and right anterior cerebral arteries; may be absent double or thin; part of circle of Willis

posterior communicating artery (PCOMM)

Connects internal carotid to posterior cerebral artery on each side; part of circle of Willis

ophthalmic artery

First branch off internal carotid artery; supplies eyes

superior division of MCA

Supplies Broca's area (motor speech) in left hemisphere

inferior division of MCA

Supplies Wernicke's area (language comprehension) in left hemisphere

anterior spinal artery (ASA)

Branch of vertebral artery; supplies anterior 2/3 of spinal cord; travels in anterior median fissure

posterior inferior cerebellar artery (PICA)

Branch of vertebral artery; supplies part of cerebellum

anterior inferior cerebellar artery (AICA)

Branch of basilar artery; supplies part of cerebellum

superior cerebellar artery (SCA)

Branch of basilar artery just inferior to PCA; supplies part of cerebellum

pontine arteries

Branches of basilar artery; supply pons

penetrating arteries (brainstem)

Branches of basilar artery; supply deeper aspects of brainstem

anterior circulation

Supplied by internal carotid arteries; includes ACA and MCA; supplies forebrain and lateral/medial aspects of hemispheres

posterior circulation

Supplied by vertebral and basilar arteries; includes PCA and vertebrobasilar branches; supplies occipital lobe thalamus cerebellum and brainstem

MCA occlusion clinical signs

Weakness and sensory loss in contralateral face and arm; potential speech deficits (aphasia if left hemisphere); potential spatial deficits or left neglect (right hemisphere)

ACA occlusion clinical signs

Weakness and sensory loss in contralateral leg and trunk; potential incontinence and prefrontal cortex impairments (poor judgment; apathy)

PCA occlusion clinical signs

Vision changes (contralateral visual field cut); hemisensory loss and hemi-body pain due to thalamic infarction; NO motor deficits

superficial cerebral veins

Veins lying on surface of brain; drain cerebral cortex

deep cerebral veins

Veins that drain deep structures (basal ganglia; internal capsule; thalamus)

bridging veins

Veins running in subarachnoid space; pierce meninges to drain into dural venous sinuses

dural sinuses

Venous channels between inner and outer layers of dura mater; drain blood and CSF from brain

superior sagittal sinus

Runs along superior surface of brain between falx cerebri and skull cap; receives CSF from arachnoid granulations

inferior sagittal sinus

Runs along free edge (bottom) of falx cerebri; drains into straight sinus

straight sinus

Runs in seam between falx cerebri and tentorium cerebelli

transverse sinuses

Runs between tentorium cerebelli and its attachment to skull (right and left)

sigmoid sinuses

S-curved continuation of transverse sinuses; drain into internal jugular vein

confluence of sinuses

Junction where superior sagittal sinus straight sinus and transverse sinuses converge

falx cerebri

Layer of dura covering mesial surface of cerebral hemispheres

tentorium cerebelli

Layer of dura encasing cerebellum

internal jugular vein

Final drainage pathway for all dural sinuses and CSF; exits skull

anterior

Front or toward front of body (brain: towards front; spinal cord: ventral side)

posterior

Back or toward back of body (brain: towards back; spinal cord: dorsal side)

superior

Above or toward top (cerebral cortex top)

inferior

Below or toward bottom

rostral

Above brainstem: front of brain; in brainstem: portion closest to cerebral cortex (upward)

caudal

Above brainstem: back of brain; in brainstem: portion toward sacral spinal cord (downward)

dorsal

Above brainstem: top of brain; in brainstem: posterior surface toward back of body (closer to cerebellum); spinal cord: posterior side

ventral

Above brainstem: bottom of brain; in brainstem: anterior surface toward front of body; spinal cord: anterior side

medial

Towards midline of brain or spinal cord

lateral

Away from midline

ipsilateral

Same side of body; laterality referenced to a specific point

contralateral

Opposite side of body; laterality referenced to a specific point

decussation

Crossing of white matter fiber tracts in CNS (e.g.; motor fibers cross at bottom of brainstem)