Cerebral vasculature Flashcards
What are the 3 major steps for the development of human brain?
- Embryonic
- Fetal
- Perinatal
What are the early stem cell lineages?
- Neuroectodermal cells –> CNS
2. Endothelio-haematopoetic cells –> vascular system
What are the vascular network?
- Vasculogenesis: De-novo formation of blood vessels
2. Angiogenesis: Growth of new blood vessels from pre-existing ones
What are the structure of the artery wall?
- Tunica media:
- smooth muscle
- External elastic lamina - Tunica Interna or Intima
- Endothelium
- Subendothelium
- Internal elastic lamina
What are the cerebral arteries?
- Pronounced internal elastic lamina
- Few elastic fibres in the media
- Thin adventital layer with no external elastic lamina
- Paucity of elastic fibres in medial layer
- No intracranial vasa vasorom exists at birth, as compared to extracranial arterial vasculature
What is the Windkessel effect?
- Account for the shape of arterial blood pressure waveform
- Interaction between stroke volume and compliance of aorta and large elastic arteries and resistance of smaller arteries and arterioles
What are the features of Windkessel effect?
- Buffering high pressure that is created by the heart
- Aorta expands - releases that expanded pressure slowly in diastole
- Prevent collapsing during cardiac cycle
- Sustain constant blood pressure in the brain
- Large arteries expand, absorb pressure and release it with elastic recoil
What is arterial stiffness due to?
Biological aging and arteriosclerosis
What is the pulse wave velocity?
- Stiffness of the arteries
2. Cuff on neck and thigh = measure the distance between them
What are the microvascular anatomy ?
- Anterior supply = Internal carotid
- Posterior supply = vertebral arteries
- Aortic arch arises from the heart
Where does the blood supply to your brain come from?
- Right common carotid
- Right vertebral artery
- Left common carotid
- Left vertebral artery
What are the variation of the aortic arch due to?
Embryological development
What leads to the major arterial structures?
6 branchial arteries in the embryo
Where does the anterior circulation originate from?
- Right common carotid artery
2. Left common carotid artery
What does the common carotid arteries arise from and what does it bifurcateinto?
- Arise from aortic arch
2. Bifurcate into External carotid artery and Internal carotid artery
Where does the vertebral arteries arise from?
Subclavian artery
Forms basilar artery
What is basilar artery?
Where 2 arteries merge and form a new vessel and do not bifurcate to form other vessels
What is the anterior circulation supplied by?
Internal carotid arteries (ICA)
What is the posterior circulation supplied by?
- Vertebral arteries
2. Basilar artery
What are the anterior and posterior circulation connected through by?
Circle of Willis
What does the external carotid arteries supply?
- Face
- Neck
- Scalp
- Partly meninges
What does the internal carotid arteries supply?
- Brain
2. Eyes
What are the branches of the external carotid artery?
- Superior thyroid artery
- Ascending pharyngeal artery
- Lingual artery
- Facial artery
- Occipital artery
- Posterior Auricular artery
- Maxillary artery
- Superficial temporal artery
(school are loosers for occluding pink money sachet)
What does the internal carotid artery bifurcate into?
- Anterior cerebral artery
2. Middle cerebral artery
What are the segments of Internal Carotid Artery?
- Cervical
- Petrous
- Lacerum
- Cavernous
- Clinoid
- Opthalmic (supraclinoid)
- Communicating (terminal segment)
(cee pink lips cocky cocky ohh cocky)
What is the blood supply to eye provided by?
Internal Carotid
What does branches of OA supply?
All structures in the orbit as well as structures in the nose, face and meninges
What supplies the eyeball?
Posterior cililary arteries
What does Circle of Willis consist of?
Bilaterally paired:
- Anterior cerebral artery
- Internal carotid artery
- Posterior cerebral artery
- Posterior communicating artery
and single
1. Anterior communicating artery
What is not included in Circle of Willis?
Middle cerebral artery (MCA)
What are the functions of Circle of Willis?
- Redundancy for collateral circulation/cross-perfusion
2. Distribution of blood pressure
What does Anterior Cerebral Artery supply?
Most of the frontal lobe and superior medial parietal lobe
What are the 5 segments of ACA?
- A1 (horizontal, precommunicating)
- A2 (vertical, post-communicating, Infracollosal)
- A3 (Precallosal)
- A4 (Supracallosal)
- A5 (Postcollosal)
What are the supplied territories of ACA?
- Orbitofrontal
- Frontopolar
- Anterior Frontal
- Middle Frontal
- Posterior Frontal
- Pre-central
- Superior parietal
- Inferior parietal
What are the perforating branches of ACA?
- Medial striate
- Heubner
- Optic nerves/chiasm
- Hypothalamus
- Anterior commissure
- Fornix
- Septum pellucidum
What are the cortical branches of ACA?
- Orbitofrontal
- Frontopolar
- Anterior/middle/posterior internal frontal
- Paracentral
- Superior/Inferior Internal parietal
- Perisplenial
What are the perforating branches of MCA?
Lenticulostriate arteries - perforating Basal Ganglia
M2 perforators
What is the superior division of MCA?
Lateroinferior frontal lobe (location of Broca’s area)
What is the inferior division of MCA?
Lateral temporal lobe (location of Wernicke’s area)
What are the anatomical variation of MCA4?
- Legend
- Early Bifurcation
- Large anterior temporal
- Co-dominant
- Superior and Inferior dominant
- Trifurcation
- Duplicate M1
- Accessory M1
What is the posterior cerebral artery supplied by?
Posterior communicating artery
What is the basilar artery supplied by?
Anterior inferior cerebellar artery
Superior cerebellar artery
What is the vertebral artery supplied by?
Posterior Inferior Cerebellar artery
What is the vertebro-basilar system?
- Vertebral arteries
2. Basilar artery
What does the critical arterial supply?
- Cervical spinal cord
- Brainstem
- Cerebellum
- Thalamus
- Occipital lobes
What is the ASPECTS score for stroke?
- Thalami (1 point each)
- Occipital lobe (1 point each)
- Midbrain (2 points)
- Pons (2 points)
- Cerebellar hemisphere (1 point each)
Where does the vertebral artery arise from?
Subclavian arteries
What does vertebral artery supply?
Posterior fossa and occipital lobes
What are the segments of vertebral artery?
- V1 - preforaminal
- V2 - Foraminal
- V3 - Extradural
- V4 - Intradural or Intracranial
What is Basilar artery formed by?
Left and right vertebral artery
only artery that is formed by confluence
What are the main branches of Basilar artery?
- Anterior Inferior Cerebellar Artery (AICA)
- Pontine arteries
- Superior cerebellar artery (SCA)
What are the arteries of posterior fossa?
- PICA
- AICA
- Superior cerebellar artery (SCA)
PICA
- Largest branch of vertebral artery
2. Highly variable origin
AICA
- Variable origin from basilar artery
2. Near abducens and facial nerve
Superior cerebellar artery (SCA)
- Origin of basilar just below P1 segment PCA
- Duplication, variable origin
- Rarely absent
What is the PICA-AICA dominance?
Calibre of arteries are not the same
What is posterior cerebral artery 1?
- Terminal branches of basilar artery
- Supplies the posteromedial surface of temporal lobe and occipital lobe including visual cortex
- Central perforating, choroidal + cortical branches
What are the segments for PCA?
- P1- precommunicating (basilar tip to pCOMa)
- P2
- P2A: anterior- sub segment within crural cistern
- P2P- posterior - subsegment in ambient cistern - P3 - Quadrigeminal (cistern behind brainstem)
- P4 - cortical - cortical segment (calcarine artery, within calcarine fissure)
What is fetal PCOM?
PCOM is larger than P1 segment of PCA and supplies bulk of blood to PCA
if bilateral BA is significantly smaller than normal
P1 either small/absent - can occur bilaterally
What is artery of percheron?
- Rare variant of posterior cerebral circulation
2. Solitary arterial trunk supplies paramedian thalami + rostral midbrain bilaterally
What are the perforators of Circle of Willis?
- Medial perforators
- Lateral perforators
- Thalamoperforators
- Thalamogeniculate
What do the lenticulostriate arteries supply?
- Basal Ganglia
2. Internal capsule/ Corona radiata
What is the lenticulostriate arteries?
- Arise basal parts of MCA/ACA
2. Penetrate anterior perforated substance
What does the lenticulostriate arteries supply?
- Basal ganglia
2. Internal capsule/corona radiata
Lateral group of lenticulostriate arteries
Around and through putamen
medial group of lenticulostriate arteries
through globus pallidus
plus artery of heubner
Choroidal arteries
Develop very early when choroid is prominent
Anterior originates from ICA or MCA
Posteromedial and Posteriolateral (branches of PCA)
Anastomose and in balance
