Week 8 Cerebral Blood Flow Flashcards
Dealing with blood supply, an arterial supply is going to the gastroc and another going to the soleus. If you lose the supply to the soleus you’ve (gained/lost) perfusion to the muscle.
lost
In really important anatomical regions we have what is called an ______ which are interconnected low pressure pipes that go through and connect other main branches. They are going to be Important from a cerebral perfusion perspective.
The closer you are to the main arterial supply where the pipe is bigger you are going to have (less/more) pressure going through. As you start to get away from the main arterial supply the pressure dips down (higher/lower).
anastomoses; more; lower
With the internal capsule, the internal capsule relays ascending info from the cord to the cortex and takes information from the cortex down to the cord level. As it passes through the corona radiata and in to the funnel that we call the internal capsule they are going to branch off to specific divisions and have specific functions within those divisions. And those divisions are going to be important because there are separate blood supplies to those capsular regions and an infarct to any particular area is going to result in some sort of a deficit we will see in respect to patients.
Coo
As far as internal blood supply to the brain goes, we have a dual system because there are (two/three) arteries that are coming off to supply the brain. The first is the (internal/external) carotid and as the internal carotid comes off of the ____ arch it separates into two branches – a (anterior/left) common carotid and a (left/right) common carotid. As it continues to rise up and dives into the skull it becomes the (right/left) internal carotid artery. Off of the right internal carotid artery we are going to get two major branches that are supplying the cortex – the (anterior/posterior) cerebral artery and the (middle/posterior) cerebral artery. The names describe what they do. The anterior cerebral artery goes to the front of the brain and the middle cerebral artery goes to the middle of the brain.
two; internal; aortic; left; right; right; anterior; middle;
The second part of the dual system – the supply tucked in between the vertebral bodies traveling within the tunnel embedded in them is going to be the vertebral system. The vertebral system comes off of the left and right (carotid/subclavian) arteries branching off into the (right/left) (subclavian/vertebral) artery. Following up into the vertebral bodies up to the skull vault. The vertebral body and the vertebral artery starts at C_ and that is important because at the level of c_ the vertebral artery is not tucked into the vertebral body region. As we start getting to C6 this is where it gets stuck and travels through the foramina in between each individual vertebral body. As that goes up the cranial vault the left vertebral artery branches off into the ____ artery and then finally the (anterior/posterior) cerebral artery to get the back aspect of the brain.
subclavian; left subclavian; C6; C7; basilar; posterior
The vertebral artery and the arterial supply is very important for the perfusion of the spinal cord.
The subclavian has important characteristics to it. Within the subclavian space is the brachial plexus. If the clavicle dislocates it will pinch off the subclavian artery and pinch off the ____ plexus which could lead to irreparable damage to the brachial plexus. You rather have a clavicular fracture than a dislocation.
brachial
The two main branches of the internal carotid artery are the ____ cerebral artery and the _____ cerebral artery that travels to the anterior part of the cortex. Off of the vertebral arteries it branches to the _____ artery. The two branches that are coming off of the basilar branch are the left and right ______ cerebral arteries.
middle; anterior; basilar; posterior
The majority of the medial aspect of the brain is perfused by the (anterior/middle) cerebral artery with the remaining aspect of the region perfused by the (middle/posterior) cerebral artery.
anterior; posterior
On the lateral aspect we have a little bit of perfusion from the _____ cerebral and a little bit of perfusion from the ______ cerebral artery. The main perfusion to the cortex on these aspects are perfused by the _____ cerebral artery.
The middle cerebral artery is huge anatomically and is very important from a function perspective. Any kind of lesion to that middle cerebral artery is going to potentially have devastating impacts on the function of the individual.
anterior; posterior; middle;
The anterior cerebral artery is composed of the ______ & _____ lobes and majority of the _____ gyrus.
The middle cerebral artery is composed of the ____, _____, & _____ lobes.
The posterior cerebral artery is composed of the ______ & _____ lobes.
frontal and parietal; cingulate; frontal, parietal, & temporal; occipital & temporal
The middle cerebral artery is the most important one and it branches off of the _____ carotid artery.
internal
As the MCA comes up off, the internal carotid goes into the cortical space. It branches off into two different portions. It branches off into a superior branch and an inferior branch. The superior branch covers the (medial/lateral) surface of the ______ and ______ lobes. The superior branch is responsible for Lateral M1 (Devising motor plan, face/UE more effected than legs), pre motor cortex (coordination of head , eyes, trunk) supplemental motor cortex (timing and sequence of movements, postural control), lateral S1, Broca’s if left, space/attention if right.
The (superior/inferior) branch is most commonly impacted by strokes.
lateral; frontal and parietal; superior
The inferior branch of the MCA covers the (medial/lateral) surface of the _____ lobe and if the left side of the brain is impacted (Wernicke’s and visual association cortices/space and attention) will be impacted and if it is the right side (Wernicke’s and visual association cortices/space and attention) will be impacted.
So you might not see as much with respects to motor deficits and motor function. But you might see more impact with cognitive aspects. Being able to take visual input and doing something with that. So those are the impacts that we have from a middle cerebral artery infarct
lateral; temporal; Wernicke’s and visual association cortices; space and attention
There’s this ring that connects all of them together in some way, shape, or form. And that’s the anastomosis backup. We call that the Circle of Willis. The Circle of Willis is an anastomotic connection that helps to keep some blood flow trickling through. So at least you can stay alive through the process if you can. But again, it’s not perfect. So here we have the Circle of Willis. The main portions of the Circle of Willis is going to be the _____ cerebral artery, ______ cerebral artery, and Not the _____, but the main branch, the internal carotid. So the MCA is still going to get some backup perfusion. But it classically does not participate within the circle of Willis. It’s going to be the internal carotid. Know it. Understand. It seems to be important to the licensing board. So we have the anterior cerebral artery coming off in the green. We’ve got the internal carotid coming off in the pink. And then we have the posterior cerebral arteries coming off in the yellow. And what we see are these interconnecting branches that form the anastomosis. So here, off the anterior cerebral artery, we have the _____ communicating artery, which is going to allow for blood flow between left and right ______ cerebral as a backup. And then down here we have the posterior communicating arteries that are going to connect to the _____ cerebral artery to the internal carotids. So if something does happen to one of these main branches, there’s a little bit of redundancy and backup built into the system. The problem is, if you look at the size of the basilar artery, you look at the size of the internal carotid. Those are big pipes. The communicating pipes and the ACA and the PCA are good bit smaller. So the issue, it’s not a high pressure system. You’re not redirecting all of the flow into the regions. Again, you’re getting a trickle. This is likely not enough to sustain brain function. It’s just enough to keep you alive. So you’re still going to have deficits at the end of the day.
There are anatomical variations in the Circle of Willis.
anterior; posterior; MCA; anterior; anterior; posterior;
Lateral view of the internal capsule
The internal capsule kinda sneaks in through the _____ to go down here into the crus cerebri and eventually down the way to the medulla, or conversely, coming up the medulla through the pons, the crus cerebri, and then eventually up to the cortex. The internal capsule holds all of the ascending and descending information that is either going to the cortex or coming from the cortex.
putamen
Internal Capsule
Anterior Limb
Anterior thalamic radiation: Thalamocortical & corticothalamic fibers - Connects the _____, _____lobe, & cingulate gyrus
The only thing that I need you to know about the internal capsule and the anterior limb right now is that it is the (anterior/posterior) most part of the internal capsule. And it’s responsible for this important structure which we call the anterior thalamic radiation. What’s important about that is, at this point in the game, what do you guys know about the thalamus? All the sensory information goes through there. So how that sensory information has to go through the thalamus before it makes its relay up into the cortical regions. So it connects the ______, the _____lobe, and the cingulate gyrus and if you lose that we’ve got some big issues in terms of function. Sensory function can be depleted. Motor function can be depleted.
thalamus, frontal; anterior; thalamus; frontal
Internal Capsule
Genu
Cortico ___/____ fibers
Primary (motor/sensory) cortex → cranial nerve motor nuclei
We have this inner aspect, the (medial/lateral) most aspect of the internal capsule that we call the genu, of the internal capsule because it looks like a knee. There’s only one thing that travels within the genu of the internal capsule. And that’s going to be cortico _____ or cortico ____ fibers. So sensory information from the facial nerves or motor input to the facial nerves. Motor input coming from M1, sensory information going to S1. So if we have disruption of the internal capsule, either through damage or through loss of blood supply we’re going to have deficits within the (face/legs). And really when we’re dealing with the internal capsule because of how deep it is. Trauma aspect is not as big as the perfusion aspect and loss of blood supply to the area.
corticonuclear/bulbar; motor; medial; nuclear; bulbar; face
Internal Capsule
Posterior limb
And then lastly, we have this aspect here, which is the posterior limb of the internal capsule. And we are looking right over this way here on the back aspect. And that is going to be motor and sensory supply for (upper/lower) extremity, _____ and (upper/lower) extremity. And there’s going to be a somatotopic organization to this. If you think about it, think about somebody laying down. Here’s the head, upper extremity, trunk, and lower extremity. So there is an organized somatotopic structure to the internal capsule.
UE; trunk, and lower
Internal Capsule
Posterior Limb
Corticospinal fibers
Central thalamic radiations: ______ & _____ fibers - Thalamus ↔ (parietal/occipital) lobe
Parietopontine fibers
Cognition region → pons → cerebellum - Sequencing of thought processes
The posterior limb of the internal capsule contains the corticospinal fibers which contain the (motor/sensory) information from M1 going down to the cord. Thalamic radiation is thalamocortical and corticothalamic, so from the thalamus to the cortex. So (motor/sensory) input with respects to upper limbs, trunk and lower limbs going from the thalamus into the cortical region. And cortical thalamic, which is information that’s coming from the cortex down to the thalamus. Again, if you lose that region, There’s going to be a good amount of deficits that you have because the relay has been shut off, the cortex can be fine, but if you can’t get information to or from, it doesn’t matter. And then lastly, we have this structure called the parietal pontine fibers, parietal lobe into the pontine regions. This is important from a cognition perspective and sequencing of thought processes. The issue here is, yes, the person’s going to have cognitive issues. But if you’re dealing with somebody who’s had a stroke and they’re trying to re-learn simple, basic steps. If you think about all the steps that you go through that you’ve learned and functional mobility from sit to stand. There’s like ten steps just in getting up. You forgotten those, you have to re-learn those. But if you’ve lost the sequence of thought processes, those 10 steps are very challenging for an individual to be able to put together and grasp.
thalamocortical; corticothalamic; parietal; motor; sensory
So coming off the MCA is this ______ artery that’s going to go into the internal capsule. The anterior _____ is also going to go into the internal capsule.
lenticulostriate; choroidal
Internal Capsule: Vascular Lesions
The anterior choroidal supplies back up to the (anterior/posterior) limb, supplying the corticospinal fibers and the thalamocortical fibers. It has (ipsilateral/contralateral) control because of where it’s coming from. If we’re dealing with the left side at this point in the game, if we are dealing with motor, it is left side internal capsule and it is going to keep continuing down until it hits the pyramidalis, and to the opposite side of the body. So if you have a lesion there, you’re going to have contralateral hemiparesis and impaired sensation. The lenticulostriate provides perfusion to most of all of the _____ capsule: Corticospinal and corticobulbar - So face, limbs, trunk. Those can all be potentially impacted. We’re going to lose thalamocortical fibers and again dealing with (ipsilateral/contralateral) hemiparesis and impaired sensation.
posterior; contralateral; internal; contralateral
The vertebral artery comes off, leading to the (basilar/vertebrobasilar) artery, which leads into the (basilar/vertebrobasilar) artery, which branches to the (anterior/posterior) cerebral artery. It’s going to be the vertebral arteries that are going to be the most important and playing the complete role with respect to brainstem blood supply.
vertebrobasilar; basilar; posterior
The basilar artery branches off on until left and right (anterior inferior/posterior superior) cerebellar artery. You can tell by the name. It supplies blood to the anterior inferior cerebral artery. But the important aspect of that is it also gives blood supply to the dorsal lateral and caudal pons and the dorsal lateral rostral medulla. The important aspect of that is, that’s where the _____ nerves and the cranial nuclei sit. But if you lose this basilar artery, there’s potential to have cranial nerve deficits.
anterior inferior; cranial
Coming off the vertebral basilar artery is the (anterior/posterior) inferior cerebellar artery, which is going to perfuse the posterior inferior aspect, the cerebellum. But more importantly, right over here, pica is responsible for (dorsal lateral/ventro medial) medulla, which is going to be cranial nerve (brain stem/nuclei), and location is going to dictate any sort of impairment that you get. We’re really more concerned about the medulla and the caudal aspect of the pons. Not so much the rostral end of the ponds because that blood supply doesn’t really become impacted by a lot of different things. So it’s a fairly robust blood supply. But these two structures here are a little bit flimsy. And if we are going to have brainstem perfusion issues, it’s going to happen one of these two structures.
posterior; dorsal lateral; nuclei;
All brainstem blood supply originates from the (basilar/vertebral) artery. The PCA supplies the (midbrain/hindbrain).
- Structures we are worried about with a PCA/midbrain perfusion issue:
- (White/Red) nucleus – rubrospinal tract
- Crus _____ – corticospinal and corticobulbar tracts
- (Anterior and posterior/Superior and inferior) colliculi – auditory and visual processing input
vertebral; midbrain; Red; cerebri; superior and inferior
Cerebrovascular Pathology (non-traumatic)
- Ischemia: cerebral vessel occlusion (ischemic stroke)
- Plaques
- Tumor cells
- Air
- Bacteria
- Tend to lodge where vessels (don’t branch/branch)
- Lead to infarction of area “downstream”
- Cerebral hemorrhage (hemorrhagic stroke)
- Damage from pressure of lack of blood flow
branch;
Cerebrovascular Pathology
Middle cerebral artery
- (Ipsilateral/Contralateral) hemiparesis
- UE > LE
- (Ipsilateral/Contralateral) sensory deficit
- 2 point discrimination, and position sense more affected than pain (UE>LE)
- DCML (more/less) affected compared to ALS
- Aphasia
- (Left/Right) side involved
- Receptive vs expressive vs global
- Spatial perception deficits
- (Right/Left) side involved
Anterior cerebral artery
- (Ipsilateral/Contralateral) hemiparesis
- LE > UE
- Contralateral sensory deficit
- 2 point discrimination, and position sense affected (more/less) than pain
- LE > UE
Posterior cerebral artery
- Visual field deficits
- Possible contralateral hemiparesis
- If (spinothalamic/ corticospinal/bulbar) fibers in crus cerebri are affected
Contralateral; Contralateral; more; Left; Right; Contralateral; more; corticospinal/bulbar
- There is (less/greater) pressure closer to the main arterial blood supply, further away from the main supply, there is (more/less) pressure driving the system
- Greatest pressure exists in the (superior portion/middle) of the cortex
- Further away from the main supply, more trickled blood supply (healthy and unhealthy individuals)
greater; less; middle;
- Watershed infarcts: occur between 2 areas that are between (anastomosing/non-anastomosing) regions
- 10-20% of CVA/Stroke Typically occur in (the young/elederly) with advanced atherosclerosis or arterial stenosis
Anterior watershed infarct
- (Sensory/Motor) deficits
- Precentral gyrus
- Expressive aphasia
- (Wernicke’s/Broca’s) area
- Behavioral changes
- Parietal multimodal cortex
Posterior watershed infarct
- Partial visual loss
- (Temporal/Occipital) lobe
- Memory impairments
- Parahippocampal gyrus
- Emotional impairments
- Limbic lobe
- Variety of language impairments
non-anastomosing; elderly; Motor; Brocas; Occipital;
Did Manipulation Cause Dissection
- Or was acute neck pain of vertebral artery dissection
- (Acute/chronic) neck pain can be a sign of vertebral artery dissection/ the process of going through a posterior cerebral artery stroke presenting with neck pain and headaches
- IMPORTANCE OF NEUROLOGIC SCREENING in acute (any) neck pain
- UMN/LMN signs
- Cranial nerve screening
Acute;
