Blood supply to the brain Flashcards
What two sources does the brain receive arterial blood from?
Internal carotids
Vertebral arteries
What does the internal carotid supply
Anterior circulation and supplies most of the cerebral hemispheres
What do the vertebral parties supply?
Posterior circulation, supplies the brainstem, cerebellum, some of the temporal lobe and occipital lobe
Two main branches of anterior circulation?
Middle cerebral artery (direct continuation of ICA)
Anterior cerebral artery
What is the major clinical distinction between anterior and posterior?
The stroke syndromes associated with each are very different
What anastomoses the anterior and posterior circulations?
The posterior communicating artery
What does the posterior communicating artery form?
Circle of Willis (Circles arteriosis)
What does the circle of Willis surround in the base of the brain?
Pituitary
Where do the internal carotid canals travel through?
Carotid canal
What is the first major branch of the ICA?
Ophthalmic artery
What does the ophthalmic artery supply?
Orbit and retina
What are the 2 main branches of the internal carotid in the anterior circulation? Which is the largest?
Middle cerebral (largest artery and has biggest territory) and anterior cerebral artery
What does the middle cerebral artery supply?
Majority of the lateral surface of the cerebral hemisphere including deep structures
What does the middle cerebral artery supply deep in the brain and via what arteries?
Lenticulostriate arteries that supply the internal capsule and the basal ganglia
What is the internal capsule?
Major white matter pathway that connects the cortex to the rest of CNS
What is the most commonly involved artery in stroke?
Middle cerebral artery
Describe the anatomical course of the anterior cerebral arteries?
Course towards the midline and arch over the corpus collosum
What do the anterior cerebral arteries supply?
The medial hemisphere
What connects the anterior cerebral arteries and what does this form?
Connected via the anterior communicating arteries to form the circle of Willis
On the cortical homunculus, what does the medial aspect correspond to?
Lower limb
On the cortical homunculus, what does the lateral aspect correspond to?
Face and upper limb
Which artery is occluded in lower limb paralysis?
Anterior cerebral artery
Which artery is occluded in upper limb paralysis?
Middle cerebral artery
Where do the vertebral arteries travel through?
Transverse foramina
What is formed from the coalition of the 2 vertebral arteries?
Basilar artery
What is unusual about the basilar artery?
Its a midline artery
What does the basilar artery bifurcates to form?
Two posterior cerebral arteries
Describe the path the vertebral artery to posterior cerebral arteries
Runs up from transverse forming to join at pons
Here they form the basilar artery
This bifurcates and courses backwards to form posterior cerebral arteries
Where does the posterior cerebral lie in particular?
Cerebrum
What does the posterior cerebral artery supply?
Occipital lobe- visual
Inferior temporal lobe
Postero-inferior aspect of the cerebrum
What are the deep branches of the posterior cerebral arteries?
Thalamoperforator
Thalamogeniculate
Occlusion of posterior cerebral can affect which aspects of function?
Visual system
Somatosensation
Brainstem
What are the multiple little branches from the basilar artery going to the pons called?
Pontine branches
What do the pontine branches supply?
Motor pathways going down to the spinal cord
Where do the pontine branches sit in the brain?
Anterior surface of the pons
What does blocking of pontine arteries lead to
‘Locked in’ syndrome
What are the 3 pairs of branches of cerebellar arteries?
Superior cerebellar
Ant. inf. cerebellar
Post. inf. cerebellar
What does the superior cerebellar artery supply?
Superior cerebellum and midbrain
What does the anterior inferior cerebellar artery supply?
Caudally, anterior inferior cerebellum
Pons
What does the posterior inferior cerebellar artery supply?
Posterior inferior cerebellum
Medulla
What does the cerebellar arteries pass over? What does this mean in terms of supply?
Pass over the brainstem therefore supply the brainstem
What is the artery that comes from the medial aspect of vertebral arteries?
Anterior spinal artery
Describe the path of the anterior spinal artery
Along midline
Anterior spinal cord
What does the anterior spinal artery supply
Anterior 2/3rds of spinal cord
When is it common to get a spinal cord rupture?
During the repair of an aneurysm
