Transcript CH10. Cerebral hemispheres and vascular supply

CH10. Cerebral hemispheres and
vascular supply
By: Laurence Poliquin-Lasnier
R2 Neurology
Outline
•
•
•
•
•
Review of the main functional cortical areas
Anterior circulation
Posterior circulation
Circle of Willis
Anatomy and vascular territories of:
a) ACA
b) MCA
c) PCA
• Clinical syndromes of the 3 main cerebral
arteries
• Venous drainage of the cerebral hemispheres
Main functional areas of the brain
Anterior and posterior circulation
4 segments of internal carotid artery
1.
2.
3.
4.
Cervical segment
Petrous segment
Cavernous segment
Intracranial/supraclinoid segment
The anterior circulation: branches of
the supraclinoid/intracranial carotid
artery
• Mnemonic “OPAAM”
•
•
•
•
•
O = Ophtalmic artery
P = Posterior communicating artery
A = Anterior choroidal artery
A = Anterior cerebral artery
M = Middle cerebral artery
The anterior circulation: branches of
the intracranial carotid artery
The posterior circulation
Circle of Willis
3 main arteries
• Anterior cerebral artery (ACA)
• Middle cerebral artery (MCA)
• Posterior cerebral artery (PCA)
• ACA and MCA arise from the internal carotid
artery
• PCA arise from the basilar artery
Circle of willis
Vascular territories of the 3 main
cerebral arteries
• Vascular territories of the superficial
cerebral structures
• Vascular territories of the deep cerebral
structures
Superficial branches of ACA
Distribution of vascular supply
Superficial branches of the MCA
Distribution of vascular supply
Superficial branches of PCA
Distribution of vascular supply
Vascular territories of deep cerebral
structures
•
•
•
•
Lenticulostriate arteries
Anterior choroidal artery
Recurrent artery of Heubner
Thalamoperforator arteries
Vascular territories of deep cerebral
structures
Artery
Lenticulostriate
From
MCA
Supply
Basal ganglia, internal
capsule
Anterior choroidal
Internal
carotid
Recurrent artery of
Heubner
ACA
Thalamoperforator
PCA
Globus pallidus, putamen,
thalamus, posterior limb
internal capsule
Head of the caudate, anterior
putamen, globus pallidus,
internal capsule
Thalamus, posterior limb
internal capsule
Lenticulostriate arteries
Superficial and deep vascular supply
of the brain
Superficial and deep vascular supply
of the brain
Clinical syndromes of the 3 main
cerebral arteries
• MCA
• ACA
• PCA
Where is the lesion?
1. R face/arm UMN weakness, broca
aphasia,+/- R face/arm cortical-type
sensory loss
Distribution of vascular supply
Where is the lesion?
1. R pure motor hemiparesis (UMN)
2. R hemiplegia, R hemianesthesia, R
homonymous hemianopsia, global
aphasia, L gaze preference
Superficial and deep vascular supply
of the brain
Where is the lesion?
1. R leg weakness (UMN), R leg cortical-type
sensory loss, grasp, dishinibition
1. R homonymous hemianopia, alexia without
agraphia
Clinical pearl: Alexia without agraphia
• Lesion in dominant (usually L) occipital
cortex extending to the posterior corpus
callosum
• Prevents processing of information in R
visual field, including written material
• Information about L visual field is
transmitted to R occipital lobe, but cannot
cross to the left to the language areas by
the corpus callosum lesion
Lacunar syndromes
• Lacune: small vessel infarct
• Ressemble small lake or cavity when
examined on pathologic section
6 major lacunar syndromes:
• Pure motor hemiparesis
• Pure sensory stroke
• Ataxic hemiparesis
• Sensorimotor stroke
• Dysarthria-clumsy hand syndrome
• Basal ganglia lacune
1- Pure motor hemiparesis
• Unilateral face, arm, leg (UMN) weakness with dysarthria
• Location:
– Posterior limb internal capsule (common)
• Lenticulostriate, anterior choroidal, thalamoperforator
– Ventral pons (common)
• Ventral penetrating branches of basilar artery
– Corona radiata
• Small MCA branches
– Cerebral peduncle
• Small MCA branches
2- Pure sensory stroke
• Sensory loss to all primary modalities in
the contralateral face and body
• Location:
– Ventral posterior lateral nucleus (VPL) of
thalamus
• Thalamoperforator branches of PCA
3- Ataxia hemiparesis
• Pure motor hemiparesis with ataxia on
same side as weakness
• Location: Same as pure motor
hemiparesis
• Vascular supply: Same as pure motor
hemiparesis
4- Sensorimotor (thalamocapsular)
• Contralateral face/arm/leg sensory loss
and weakness +/- dysarthria
• Location:
– Posterior limb internal capsule and either
thalamic VPL or thalamic somatosensory
radiations
• Thalamoperforator arteries or
lenticulostriate arteries
5- Dysarthria-clumsy hand
• Facial weakness, dysarthria, dysphagia,
and slight weakness and clumsiness of
one hand
• Location:
- Pons
- Pontine arteries
- Genu of internal capsule
6- Basal ganglia lacune
• Hemiballismus or asymptomatic
• Locations:
– Caudate, putamen, globus pallidus, or
subthalamic nucleus
• Lenticulostriate, anterior choroidal,
thalamoperforator, or heubner’s arteries
Overview of venous drainage
• Superficial veins drain into the superior sagittal sinus
and cavernous sinus
• Deep veins drain into great vein of Galen
• Majority of veins ultimately drain to the internal
jugular veins
• Superior sagittal sinus –> transverse sinuses >sigmoid sinus -> jugular foramen to become the
internal jugular vein
• Cavernous sinus (int carotid artery, CN III-IV-V-VI) >superior petrosal sinus -> transverse sinus
• Cavernous sinus -> inferior petrosal sinus ->internal
jugular vein
Deep venous drainage
• Internal cerebral veins, basal veins of
Rosenthal, and other veins ->great cerebral
vein of Galen -> joined by inferior sagittal sinus
–> to form straight sinus
• Confluence of sinus (torcular Herophili) =
superior sagittal sinus + straight sinus +
occipital sinus
• Confluence of sinus drained by transverse
sinus
Overview of venous drainage
Deep venous drainage
Clinical scenario #1
• ID: 67yo woman
• PMHx: HTN, PVD, smoker
• HPI: after breakfast, she tried to stand up and
suddenly felt she could not support her weight ->
fell -> 911
• Physical:
• Alert & oriented
• Unaware at times of L sided weakness
• Language fluent
• CN normal except minimally decreased L
nasolabial fold + mild dysarthria
Clinical scenario #1
• Motor: 5/5 except 1-2/5 in L leg prox and distal
and 4/5 prox L arm
• L leg hyperreflexia, L Babinski
• Sensory: inconsistent decreased response to
pinprick on L
• Tactile extinction on L
• One month later, partially recovered power,
but feels that her L arm is out of control, grasp
onto things without her being aware and would
have to use her R arm to release the grasp
• When distracted, can use both arms normally
Where is the lesion?
• R primary motor cortex foot area
• Supplementary area given Alien hand
syndrome
• Adjacent to R frontal and R parietal lobes
• R anterior cerebral artery occlusion
Clinical scenario #2
•
•
•
•
ID: 52F
RFC: difficulty raising L arm
PMHx: HTN, smoker
HPI: noticed last night inability to raise L
arm to grasp cup of coffee. This mvt
caused her L arm to flop up in the air and
knock the coffee on the floor
• Physical:
• R carotid bruit
Clinical scenario #2
• Decreased L arm power proximally (4-/5
deltoid, tricep 4/5, bicep 4+/5, 5/5 distally)
• Decreased L leg power proximally
(iliopsoas 4/5) and rest 5/5
• L hyperreflexia arm and leg, L babinski
• Sensory N
• N FTN
• Falls to the left on tandem gait
Where is the lesion?
• Unilateral proximal arm and leg weakness
• Man in the barrel
• Contralateral motor cortex proximal arm
and leg area, and trunk
• ACA-MCA watershed area 2ary
decreased right carotid perfusion
Watershed areas
Conclusion
• 3 main cerebral arteries
– ACA, MCA, PCA
• Anterior circulation composed of internal
carotid artery that leads to ACA and MCA
within the circle of willis
• Posterior circulation arises from
vertebrobasilar system and leads to PCA
within the circle of willis
Conclusion
• ACA supplies medial frontal and medial
parietal lobes (sensorimotor cortex for
lower extremities)
• PCA supplies the medial and inferior
occipital and temporal lobes (primary
visual cortex)
• MCA supplies entire lateral surface of the
brain (face and arm sensorimotor regions
+ association cortex)
Conclusion
• MCA deep territory supplies internal capsule
and most of basal ganglia
• ACA deep territory supplies anterior basal
ganglia and internal capsule
• PCA deep territory supplies thalamus, midbrain,
midbrain, posterior internal capsule
•
Conclusion
• Venous drainage occurs via superficial and deep
cerebral veins
• Superficial veins drain into superior sagittal sinus
and cavernous sinus
• Deep veins drain into great vein of Galen
• Ultimately all venous drainage reaches internal
jugular vein mostly via transverse and sigmoid sinus