Blood Supply

What are the two major arterial systems supplying the CNS?

Carotid system and vertebral system

What artery is the source of the anterior circulation system?

Carotid artery

What artery is the source of the posterior circulation?

Vertebral artery

Where does the right common carotid originate?

Brachiocephalic trunk

Where does the left common carotid originate?

Aortic arch

At what vertebral level does carotid bifurcation occur?

C6 Cervical Vertebra

What does the external carotid artery supply?

Face and neck

What does the internal carotid artery supply?

Central nervous system

What is the first branch of the internal carotid artery?

Ophthalmic artery

Where do the vertebral arteries originate?

Subclavian arteries

Where do the vertebral arteries enter the CNS?

Through the foramen magnum

What is the first branch of the vertebral artery?

Posterior inferior cerebellar artery (PICA)

What do the two vertebral arteries form when they join?

Basilar artery

What is the Circle of Willis?

A redundant arterial connection between anterior and posterior circulation

What two arterial systems are connected by the Circle of Willis?

Carotid and vertebral systems

What structures does the Circle of Willis surround?

Pituitary gland, mammillary bodies, and optic nerve (CN II)

Why is arterial redundancy in the Circle of Willis important?

It can provide alternate blood flow if an artery becomes blocked

What brain region does the anterior cerebral artery (ACA) supply?

Frontal lobe of both hemispheres

Where does the ACA travel relative to the corpus callosum?

Superior to the corpus callosum

What connects the left and right anterior cerebral arteries?

Anterior communicating artery

What is the clinical importance of the anterior communicating artery?

It provides an anastomosis between the two ACAs

What brain regions does the middle cerebral artery (MCA) supply?

Temporal, parietal, and frontal lobes

Where does the middle cerebral artery travel?

Laterally along the cerebral hemispheres

What arteries are highly implicated in basal ganglia stroke?

Lenticulostriate arteries

What do the posterior communicating arteries connect?

The carotid/anterior circulation with the vertebral/posterior system

What brain region does the posterior cerebral artery (PCA) supply?

Occipital lobe

What artery connects the PCA to the anterior circulation?

Posterior communicating artery

What artery supplies the posterior circulation before the vertebral arteries form the basilar artery?

Posterior inferior cerebellar artery (PICA)

What does PICA stand for?

Posterior inferior cerebellar artery

What does ACA stand for?

Anterior cerebral artery

What does MCA stand for?

Middle cerebral artery

What does PCA stand for?

Posterior cerebral artery

What does SCA stand for?

Superior cerebellar artery

What is ataxia?

Lack of coordination and balance

Which brain region is associated with ataxia?

Cerebellum

Which arteries are associated with cerebellar ataxia?

Anterior, posterior, and superior cerebellar arteries

What is auditory agnosia?

Inability to recognize or understand spoken sounds

Which brain region is associated with auditory agnosia?

Temporal lobes

Which cerebral arteries are associated with auditory agnosia?

Middle and posterior cerebral arteries

What is Broca's aphasia?

Non-fluent speech

Which brain region is associated with Broca's aphasia in the lecture?

Temporal lobes

Which artery is associated with Broca's aphasia in the lecture?

Middle cerebral artery

What vascular variation is described as having a "horns" pattern?

Bovine anatomical variation

What does asymmetrical carotid origin increase?

Shear stress and altered hemodynamic flow

What vascular disease risk is associated with altered carotid hemodynamics?

Increased atherosclerotic disease risk

Which hemisphere has more strokes in the normal population according to the lecture?

Left hemisphere

What can a bovine anatomical variation increase?

Overall stroke risk and stronger left-sided stroke presentation

What is a berry aneurysm?

An aneurysm associated with vessels of the Circle of Willis

Which cranial nerve can be impinged by a berry aneurysm according to the lecture?

CN III (oculomotor nerve)

What eye movement deficit can occur with CN III involvement?

The eye may turn outward and/or downward

What is diplopia?

Double vision caused by the eyes pointing in different directions

What is ptosis?

A droopy or closed eyelid

What is mydriasis?

A dilated pupil

What near-vision problem can occur with CN III involvement?

Difficulty focusing on close-up objects

What happens if the Circle of Willis is incomplete or diseased?

It is less effective at compensating for arterial blockages

What can an ineffective Circle of Willis increase the risk of?

Ischemic stroke

Why can Circle of Willis disease cause ischemic stroke?

Reduced oxygen supply to brain tissue

What can weak arterial walls in the Circle of Willis increase the risk of?

Aneurysmal rupture

What can aneurysmal rupture cause?

Hemorrhagic stroke

What vascular condition in the Circle of Willis is associated with Alzheimer's risk?

Severe atherosclerosis

How does the venous system differ from the arterial system?

Venous drainage does not follow the same parallel arrangement as arterial supply

Where is the superior sagittal sinus located?

Along the superior border of the falx cerebri

Where is the inferior sagittal sinus located?

Along the inferior border of the falx cerebri

What do the dural sinuses eventually form at their confluence?

Confluence of sinuses