EXTRACRANIAL ANATOMY
The blood flow to the brain is largely supplied by how many vessels?
4
This vessel is the most common site of stroke and is a popular vessel for arterial stenosis and occlusion.
The MCA
This is the short vessel that connects the A1 ACA segments.
The ACOM- Anterior Communicating Artery
This artery divides into the MCAs and ACAs
The Terminal ICA
These arteries make up the posterior circulation.
The Vertebral and Basilar arteries
This vessel is the main branch of the carotid artery.
The CCA
These arteries are formed from the terminal basilar artery.
This collateral pathway connects the anterior and posterior circulation.
The PCOM-posterior communicating artery
The first branch of the ICA in the cerebral segment.
The ophthalmic artery
These arteries arise from the subclavian arteries
The vertebral arteries
What percentage of blood flow is supplied to the brain via the ICA?
75%
What are the 3 segments of the ICA Siphon
Parasellar, Genu, Supraclinoid
This collateral pathway is used due to proximal ICA occlusion and is a branch of the ECA.
The ophthalmic artery
A larger ACOM is typically accompied by hypoplasia of this vessel segment.
A1 ACA
This artery usually originates from the lower border of the pons extending anteriorly and superiorly to form the PCAs.
The basilar artery
These 4 segments make up the ICA.
cervical, petrous, cavernous, and terminal(cerebral)
Approximately what percentage of the population has a normal Circle of Willis
20%
This vessel is the most common site of aneurysms associated with subarachnoid hemorrhage.
The ACOM
This is a common site of congenital aneurysms, approximately 25% of all intracranial aneurysms.
The MCA bifurcation
The most common PCA segment to be affected by occlusive disease.
The P2 segment
What type of changes usually occur at the origins of the vertebral arteries?
Atherosclerotic
This is the most common hypoplastic segment of the Circle of Willis
The A1 ACA
With this collateral channel, you can observe which circulation(anterior/ or posterior) is being fed by observing which direction the PCA is flowing.
The PCOM
This vessel is named after the "S" curve it creates in the brain.
The ICA siphon
This artery gives rise to numerous branches.
The basilar artery