Lecture 6 - Blood Supply of the Brain Flashcards
What fissure/sulci does the ACA run through?
Longitudinal fissure
What fissure/sulci does the MCA run through?
lateral sulcus
What fissure/sulci does the PCA run through?
transverse fissure
What percentage of our body weight is the brain?
2%
What percentage of blood supply goes to the brain?
20%
Does gray or white matter have more blood vessels? Why?
Gray matter more than white
- gray matter has the cell bodies, neurons, glia and therefore needs more energy and more blood supply
- White matter contains axons, which need less energy/blood supply
What two arteries supply the brain?
- anterior division: internal carotid artery
- posterior division: vertebral-basilar artery (ascends through transverse foramen of vertebrae into foramen magnum)
What supplies the anterior division of the brain?
the internal carotid artery
What supplies the posterior division of the brain?
the vertebral-basilar artery
What are some of the major branches of the internal carotid artery ?
- anterior cerebral artery
- middle cerebral artery
- opthalamic artery
- anterior choroidal artery
- posterior communicating artery
What is important about the opthalamic artery in the anterior brain?
first branch of the internal carotid, follows the optic nerve through the optic canal for the eye
What is important about the antrior choroidal artery?
from IC, forms choroid plexus in ventricles for CSF
What is important about the posterior communicating artery?
forms an anatomoses with the basilar artery and connects anterior brain blood supply with posterior brain blood supply
What does the vertebral basilar artery split into?
- vertebral artery (2 on each side)
Why is the vertebral artery at the C6 transverse foramina important?
it crosses over only at C6, which is where dislocations or disc herniations can happen, which can compress the vertebral artery leading to nausea, vomiting, etc.
What does the vertebral artery form?
- anterior spinal artery
- posterior inferior cerebellar artery (PICA)
-> forms the posterior spinal artery
Why is PICA important?
important to cerebellar functions
- from the vertebral artery
What does the vertebral-basilar artery give off?
the basilar artery at the pontomedullary junction
What does the basilar artery give off?
- anterior inferior cerebellar artery (AICA)
- pontine arteries
- superior cerebellar artery (SCA)
- posterior cerebral artery (PCA)
What is important about the PCA?
1st CN oculomotor nerve runs through the SCA and PCA, if an aneurysm happens here it will compress the nerve!
A patient fractured the basal neurocranium around the jugular foramen. Which nerves coursing through would be compromised?
CN IX, X, and XI
A patient fractured the basal neurocranium around the foramen ovale. Which nerve coursing through would be compromised?
trigeminal nerve - mandibular branch
What is the circle of willis?
9 members, anastomosis of anterior/posteiror divisions
What are the 9 members of the circle of willis?
- anterior communicating artery
- ACA x 2
- Internal carotid artery x2
- Posterior communicating artery x2
- PCA x2
What artery is NOT involved in the circle of willis?
the MCA
What percentage of the population has a typical circle of willis?
only 30%, huge veriations