[SPEAKER_00]: Hello and welcome back to ACRAC.
[SPEAKER_00]: I'm Jed Wolpa and we are back with another fantastic keyword episode with the one and only Dr. Tim Kaistura and we today are going to talk about central and peripheral nervous system anatomy.
[SPEAKER_00]: Super high yield, lots of questions on this come up on ITEs and board exams all the time.
[SPEAKER_00]: So, Tim, thanks for coming back to tackle this one.
[SPEAKER_01]: I pleasure as always, and I promise we'll get to the nervous system in anime, but I have a couple things to take care of at the top.
[SPEAKER_01]: First, I will thank you to Crystal Wayne, one of our amazing Hopkins medical students.
[SPEAKER_01]: She helped me comb through the entire ABA content outline in all the accurate episodes to better understand what we've covered well so far, and what still needs to be covered on the keyword episode.
[SPEAKER_01]: So thank you again.
[SPEAKER_01]: It was a big effort.
[SPEAKER_01]: Thanks for listening.
[SPEAKER_00]: That's awesome.
[SPEAKER_01]: And I'd like you to make a plug again for any request for topics or comments about the keyword episode send those to a crack at a crack dot com.
[SPEAKER_00]: Please do.
[SPEAKER_01]: Um, second, spending some time in the archives gave me an idea to kick off the keyword episodes.
[SPEAKER_01]: We're going to do a little space repetition and reinforce some previous concept.
[SPEAKER_01]: So, Jed, sorry to put you on the spot right from the top of the episodes, but it's time to review some old questions.
[SPEAKER_00]: I love this.
[SPEAKER_00]: I think this is fabulous.
[SPEAKER_00]: Let's do it.
[SPEAKER_01]: All right.
[SPEAKER_01]: Number one, a patient with a hyperfunctional benign parathyroid adenoma has undergone a successful parathyroid activity with no apparent intraoperative complications, which of a following is standard of care postoperatively for vispation.
[SPEAKER_01]: A, phosphorous infusion for at least 14 hours, B, intermittent monitoring of calcium with repulsion as necessary, or C, intermittent monitoring of potassium with repulsion as necessary.
[SPEAKER_00]: great taking us back to our endocrine episode and so hopefully folks remember that when we have a parathyroidectomy or a thyroidectomy for that matter the concern is that there may be not enough parathyroid hormone left I'd parathyroid organ left to
[SPEAKER_00]: allow calcium homeostasis and so calcium can get very low and so the main thing we want to be thinking about is monitoring calcium and then of course we're pleading in this necessary and if you've ever seen someone who is profoundly hypo calciumic after one of these surgeries it is not hard to miss they get all the classic signs they can't open their hands they get tetanus it's really really interesting so um and then it goes away when you give them the calcium so definitely the calcium is what we want to monitor
[SPEAKER_01]: Absolutely, and you alluded to this.
[SPEAKER_01]: If you take out the thyroid, you may inadvertently take out the parathyroid.
[SPEAKER_01]: It is not a side effect of taking out just thyroid to issue that is all you get.
[SPEAKER_00]: Exactly.
[SPEAKER_01]: Question number two, which of the following qualifies toward the quality improvement portion of the current ABA maintenance of certification guidelines?
[SPEAKER_01]: A attending immortality and morbidity conference be completing 30 milk and minute questions a quarter or see presenting immortality at a mortality and morbidity conference.
[SPEAKER_00]: great so folks who are trainees maybe don't know this that well though we did go over this so hopefully you know a little more than you did before you listen to our episode on this but uh it's important to know that there are different pieces of of the kind of puzzle of what you have to do to maintain your certification your board certification one is doing 30 locomotive in questions every quarter but that does not count for the quality improvement portion
[SPEAKER_00]: that is just the mocha minute on going learning portion.
[SPEAKER_00]: So for the quality improvement portion, there's a whole list of things that you can do, each is worth a certain amount of the total that you need.
[SPEAKER_00]: And one of them is presenting at a more bit of immortality conference.
[SPEAKER_00]: Just attending though does not count.
[SPEAKER_00]: So you have to present and that's the right answer here.
[SPEAKER_01]: Great.
[SPEAKER_01]: 3.
[SPEAKER_01]: Which of the following criteria is not present in both a post-annuance use of discharge scoring system in the electricity scoring system?
[SPEAKER_01]: A blood pressure, B, nausea and vomiting or C activity level.
[SPEAKER_00]: great and this is one of those things that i find very tricky because in my mind it's and the way i remember it actually is that i think it's the thing that absolutely seems like it should be included but it's not which is nausea and vomiting uh... i think you can also think that blood pressure like that's really crucial you obviously shouldn't send someone home if they're going to pass out immediately uh...
[SPEAKER_00]: activity level kind of maybe along those same lines if they can't get up and walk without getting orthostatic hypotentic that you know is dangerous whereas you can go home even if you are nauseous or even vomiting people vomit at home all the time right so that is not pleasant and ideally we would not do it but it's something that in I guess that's one way to think about it that is not prohibitive
[SPEAKER_01]: Yeah.
[SPEAKER_01]: You nailed it.
[SPEAKER_01]: It's super strange.
[SPEAKER_01]: It is.
[SPEAKER_01]: It hangs us up and impack you all the time, extends back to length of state, but is not part of the discharge scoring system.
[SPEAKER_01]: Great.
[SPEAKER_01]: Question four, in the last one of our review, transfusion with which of a following blood products carries the highest risk of the recipient developing transfusion related acute lung injury.
[SPEAKER_01]: Is it a fresh frozen plasma, b a ferries, just platelets, or c pro-frambin complex
[SPEAKER_00]: Yeah, and we've gone over this one too.
[SPEAKER_00]: So it's definitely FFP or fresh frozen plasma that carries the highest risk of trolley.
[SPEAKER_00]: The, because it's in the plasma that is the causative agent and obviously you're going to have more plasma.
[SPEAKER_00]: You can have plasma in there is some going to be some plasma in other blood products, but obviously fresh protein plasma is the main one.
[SPEAKER_00]: Until that's the reason.
[SPEAKER_01]: All right.
[SPEAKER_01]: Now, let's get to today's topic.
[SPEAKER_01]: This sits in the basic portion of the ABA content outline, and specifically we'll be covering Section C, or we get in based basic and clinical sciences.
[SPEAKER_01]: The first one in a list there is the central and peripheral nervous systems anatomy.
[SPEAKER_01]: They want us to cover one the brain, including the cerebral cortex, and within that the cerebellum brings them in a couple of other topics.
[SPEAKER_01]: Two, the spinal cord and spine with a few subcategories that will hit, three the meninges for the parasympathetic nervous system, and then five the sympathetic nervous system.
[SPEAKER_01]: and they give us a few subsets that they really want us to hone in on.
[SPEAKER_01]: So that's what we'll get to today.
[SPEAKER_01]: And as always, we can't become friends of here.
[SPEAKER_01]: We'll focus on the subset of these things that seem to get tested the most will not be a comprehensive review.
[SPEAKER_01]: Starting from the top with a brain, for our purposes, we're going to divide into three main parts.
[SPEAKER_01]: The forebrain, the brain's femenahine brain.
[SPEAKER_01]: The forebrain will split into the cerebrum and the valmus, the brain's femenahine to the midbrain ponds and medulla, and the major portion of the hindbrain is the cerebellum.
[SPEAKER_01]: The most testable topics involve the motor and sensory areas, as well as various nuclei whose function are related to physiology, pertinent to anesthesia management in some way.
[SPEAKER_01]: So we'll focus on those.
[SPEAKER_01]: Key concept one, working our way from the top down, the cerebral cortex is divided into four major areas.
[SPEAKER_01]: From the back and wrapping around are the frontal, parital, occipital, and temporal lobes.
[SPEAKER_01]: And the central solace is a groove that runs between the frontal and parital lobes.
[SPEAKER_01]: The lateral fissure is another easily identifiable groove that runs between the temporal and frontal lobes, and both are pretty obviously recognizable in any diagram or picture, and don't be surprised if you see that on the test.
[SPEAKER_01]: The pre-central gyros in the frontal lobe control the motor function while the post-central gyros in a parietal lobe are responsible for somatosensory.
[SPEAKER_01]: things.
[SPEAKER_01]: The visual cortex in the visual cortex is in the cepadolob and an auditory cortex is in the temporal lobe and a couple of other tested things up here in the cortex are speech comprehension which occurs in wiring keys area in auditory cortex makes sense that comprehension is where the auditory cortex is.
[SPEAKER_01]: While speech formation occurs in brokers area and that's closer to the primary mode of cortex so you'd expect formation to happen there.
[SPEAKER_01]: anything you want to add there.
[SPEAKER_00]: No, I think that's great.
[SPEAKER_00]: This is really takes you back right to first year med school when you had to learn all this neuro anatomy, but it does get tested.
[SPEAKER_00]: So, you know, it is good to at least have the major stuff in your mind.
[SPEAKER_00]: No pun intended.
[SPEAKER_01]: All right.
[SPEAKER_01]: And then some more of it importantly, I then have shown up on tests.
[SPEAKER_01]: We'll be our key concept too.
[SPEAKER_01]: A, the respiratory centers, they are in the medulla.
[SPEAKER_01]: The dorsal are responsible for inspiration and the ventral are for expiration, just something you have to know by get tested.
[SPEAKER_01]: B, Volokes Surrealius, it's a panteen structure.
[SPEAKER_01]: And it is active during alertness and weightfulness.
[SPEAKER_01]: So I still have consciousness.
[SPEAKER_01]: see the ventral lateral pre-optic nucleus inhibits the weight-promoting areas and is necessary for normal sleep.
[SPEAKER_01]: Indeed, the hypothalamus, including specifically the pre-optic area and posterior hyperthalamus, are responsible for a formal regulation.
[SPEAKER_01]: So sort of a hodgepodge of things that will come across in anesthesia.
[SPEAKER_01]: Write it for some questions, Fred.
[SPEAKER_00]: Let's do it.
[SPEAKER_01]: All right, one.
[SPEAKER_01]: Reduce activity in which brainstem structure is associated with reduced consciousness.
[SPEAKER_01]: A, ventralateral pre-optic nucleus, B, look as serrilius, or C, periactylethyl gray area.
[SPEAKER_00]: Yeah, and again, some of this issues have to memorize it, but I'll tell you how I remember that the locus surrealis is involved with reduced consciousness.
[SPEAKER_00]: And that is that locus sounds like focus.
[SPEAKER_00]: And so in my mind, that's like you're focusing your wake, you're focused as opposed to being more sleep, more having low reduced level of consciousness and being not focused, right?
[SPEAKER_00]: So it's not perfect, but that's there.
[SPEAKER_00]: Now you can get a little tricky because, as you said, the eventual lateral pre-optic
[SPEAKER_00]: inhibits weight promoting areas and it's necessary for a normal sleep.
[SPEAKER_00]: So if you start to think focus and sleep, you might get in there But if you think focus as in the area that has to do with reduced consciousness Then locusts are really as maybe you can get to that a little better that way As we said, the ventralateral pre-optic nucleus has to do with normal sleep so a little different than Reduce consciousness, though though that's tricky and
[SPEAKER_00]: the periactyl, a periactyl, gray area does not have to do with reduced consciousness.
[SPEAKER_01]: Perfect.
[SPEAKER_01]: Number two.
[SPEAKER_00]: And that's it.
[SPEAKER_00]: Let me just ask you.
[SPEAKER_00]: I mean, do you have a better way than I just described to differentiate between the ventralateral pre-optic nucleus and the locus to really is, because that is a little confusing, right?
[SPEAKER_00]: I'm both are related to reduced consciousness just in little different ways.
[SPEAKER_01]: I don't, I like the focus focus, I haven't heard that before, but I, to keep them straight just think of what happens if you activate those areas.
[SPEAKER_01]: So activation of locusts are areas, is alertfulness and weakness, consciousness, activation of the ventral lateral pre-optic nucleus promotes sleep, so it's sort of inhibits those others.
[SPEAKER_00]: There you go.
[SPEAKER_00]: That's what I was missing.
[SPEAKER_00]: So, yes, so it's quite, and this is a good point because you have to pay close attention to the question stem.
[SPEAKER_00]: So, it's at reduced activity in which structure.
[SPEAKER_00]: So, if it had said activity, that would have been maybe impossible to decide between M. B.
[SPEAKER_00]: But because it's at reduced activity, that points you to the locus to really is because reduced activity in the ventral lateral prepping in place would actually be promoting weightfulness.
[SPEAKER_01]: Yeah, or inhibiting the promotion of sleep.
[SPEAKER_01]: All right, so matter sensory evoked potentials are being monitored by an intraoperative neurophysiology monitoring technician.
[SPEAKER_01]: The signal that is being recorded is from A, the post-central gyros, B, the precentral gyros, or C, the primary motor cortex.
[SPEAKER_00]: Great.
[SPEAKER_00]: And so, you know, again, some of this is memorization, it's going to be the post central gyros, but also if you remember, as you said earlier, that the post central gyros has to do with sensation and the precentral gyros with motor, then that helps you this is a metal sensory, so post central gyros.
[SPEAKER_00]: The other thing you can use to remember this is that
[SPEAKER_00]: the post at, if you've done in a season the OR, you know that when there are neuro-monitoring the neuro-monitoring folks are there, the neuro-monitoring technician, they're sitting there.
[SPEAKER_00]: I think they have their own little post, I think of it as they have a post in the OR.
[SPEAKER_00]: They're sitting there at their post, and so the post-central gyros is what they're monitoring.
[SPEAKER_00]: Now, of course, they could be monitoring motors too, so that doesn't really work for all their monitoring.
[SPEAKER_00]: But if you think of their sensation of being at their post,
[SPEAKER_00]: that post-central diaries is how they're monitoring sensation.
[SPEAKER_00]: I'm sure there's much better namanics for remembering that than what I just gave you, but that is one you can use.
[SPEAKER_01]: Yeah, and then one other just test-taking, sometimes you can get things right, even if you don't know exactly what they're aiming at, but if you happen to remember that be the pre-central drivers or see or the same as see where the primary motor cortex are, you know those are the same answer.
[SPEAKER_00]: Yeah, and also you should be able to get rid of C at at the very least because it's asking about sensory, so it's not going to be the primary motor cortex, so you could get, you just if you know nothing, you could get rid of C just by reading carefully, and then you'd have a 50 50 shot.
[SPEAKER_00]: Perfect.
[SPEAKER_01]: A question three, Elysian and what's in which one of the areas can be responsible for a control lateral weakness following a thrombone ballad stroke, A, cerebellum, B, precentral
[SPEAKER_00]: So now again, we're talking about motor, this is weakness, and so that's going to take out the post-central gyrus, which we just talked about as having to do with sensory.
[SPEAKER_00]: And so we're now deciding if you remember back from neuroanatomy, neuroblock in medical school, right?
[SPEAKER_00]: The cerebellum injuries to the cerebellum are not controlled at all, they cause ifs the lateral problems, often things with balance, and that kind of stuff, but still can't be the answer because this says, control lateral, and so that leaves you just with
[SPEAKER_01]: Great.
[SPEAKER_01]: And question four, a mouse train is discovered that is highly sensitive to serotonin's storm syndrome.
[SPEAKER_01]: Which of the following brain areas is likely involved in the pathogenesis of serotonin's storm?
[SPEAKER_01]: A, the ventralateral pre-optic nucleus, B, locuserilius, or C, the hypotherlamic pre-optic area.
[SPEAKER_00]: Right, so here again, I don't have a great way to know this other than you have to know it, which is that, as we've talked about, the ventralateral pre-optic nucleus has to do a sleep.
[SPEAKER_00]: The locusts are really with a wakefulness and level of arousal, and so then that leaves the hypotherlamic pre-optic areas, is what has to be the right answer here.
[SPEAKER_01]: Yeah, and I don't have a great way of memorizing these either.
[SPEAKER_01]: It's why there are a bunch of questions just repeating these things for us to hammer them home.
[SPEAKER_01]: The only other trick about this question is, remember, in that serotonin storm along with a militant hypothermia, or a couple of your high-temperature states that you can see in.
[SPEAKER_01]: in anesthesia.
[SPEAKER_00]: Yeah, great.
[SPEAKER_01]: All right, next we'll move on to the Spindon spinal cord.
[SPEAKER_01]: And here there are a couple of things that are really commonly tested for T-brille anatomy and it's association to spinal nerve root dislocation and blood supply to the spinal cord.
[SPEAKER_01]: Key concept three for the vertebrae.
[SPEAKER_01]: There are seven cervical, 12 thoracic and five
[SPEAKER_01]: And there's a small vestigial, vestigial vertebrae.
[SPEAKER_01]: A few of these are a little bit specialized.
[SPEAKER_01]: See one, or atlas, is ring-like and has no body.
[SPEAKER_01]: C2 also known as axis has a superially protruding undentified process.
[SPEAKER_01]: C7 is notable because it's the first vertebrae to not have a bifit spinous process unlike the other cervical vertebrae and it's the most prominent spinous process as you're palpating the back.
[SPEAKER_01]: And then the thoracic vertebrae have long inferiorly angled spinus processes compared to the relatively short blunt posteriorly angled lumber spinus processes.
[SPEAKER_01]: He comes up for the spinal cord, extends from the level of two-level of L1 and adults and L3 and children.
[SPEAKER_01]: That'll be a test question in of itself often.
[SPEAKER_01]: On the anterior posterior nerve roots at each spinal level, join one another and exit through the introvert deeper for Amina and they form spinal nerves C1 to S5.
[SPEAKER_01]: At the cervical level, these nerves arise above their vertebrae, but starting at T1, they exit below their vertebrae.
[SPEAKER_01]: As a result, the eighth cranial nerve C-8 is the exception coming out between C-7 and T1.
[SPEAKER_01]: Noblebo-Vercibral ligaments include the ligament and flavone, which runs along the anterior surface of the vertebral bodies, so close to the spine, spinal cord, the inner sphinus ligaments are between the sphinus processes and the superspinus ligament which connects the tips of the sphinus processes sort of the most posterior.
[SPEAKER_01]: And our last key concept in this section, the blood supply, to the spinal cord, comes from a single anterior spinal artery impaired posterior spinal arteries.
[SPEAKER_01]: The anterior spinal artery originates from the vertebral artery at the base of a skull, and it supplies the anterior two-thirds of the cord.
[SPEAKER_01]: The posterior arteries originate from the inferior posterior inferior cerebellar arteries, and they supply the remaining one-third of the cord.
[SPEAKER_01]: both anterior and posterior spinal arteries get additional flow from thoracic and recostal lumbar arteries, so it's not just that superior portion that provide to all of a blood flow.
[SPEAKER_01]: And the most notable of these is the relatively large artery of Adam Kevich, or the arteria reticularis mechna.
[SPEAKER_01]: It rises from the eorda, often on the left side, and is a major source of the anterior blood supply to the lower two-thirds of the anterior chord.
[SPEAKER_00]: Great.
[SPEAKER_00]: And that comes up a lot, right, because of aortic surgery.
[SPEAKER_00]: And if you lose blood flow to the arterioredicularis magna, then that can have real risk for paralysis because of spinal cortischemia.
[SPEAKER_01]: Yeah.
[SPEAKER_01]: And it just lets an intestine in so many ways.
[SPEAKER_01]: Do you know how the spinal cord is organized?
[SPEAKER_01]: Do you know where the blood supply comes from?
[SPEAKER_01]: Do you know which portions are supplied
[SPEAKER_01]: Sure, I'm sure we'll see a question today.
[SPEAKER_01]: Great question five.
[SPEAKER_01]: A patient has a lateral discerningation between L2 and L3, which spinal nerve is most likely affected.
[SPEAKER_00]: So if they have a lateral discerningation between L2 and L3, we want to know what nerve root is coming out above L2 and below.
[SPEAKER_00]: we're just coming up above L3 and below L2.
[SPEAKER_00]: Does that, that's what we're asking?
[SPEAKER_01]: So yeah, basically, if you have something coming out at um, if the herniation is lateral between L2 and L3, what has already come out that would be impenished at that location?
[SPEAKER_00]: right and so let's go back to what you said although let's make sure we're doing this right so the cervical nerve roots arise above their vertebrae and then below that they arise below it right so we're then saying that below L2 is the L2 root nerve root and below L3 is the L3 nerve root right okay so then
[SPEAKER_01]: No, you've got it, so here it would be a L2.
[SPEAKER_01]: And I think we have one of the things to look out for as well is whether it's a central herniation or a lateral herniation.
[SPEAKER_01]: Or if the lateral herniations will sort of hit the roots that have already exited and impinged on the spinal nerve roots that are out through the piramina.
[SPEAKER_01]: Um, and any central herniation may impinge, uh, routes that have formed in the spinal cord, but haven't exited yet, so you might get symptoms in, uh, lower areas there.
[SPEAKER_00]: Stay with us.
[SPEAKER_00]: We'll be right back.
[SPEAKER_00]: all right, and we're back.
[SPEAKER_00]: Okay, fabulous.
[SPEAKER_00]: So as we said, the nerve roots come out after the cervical cord below.
[SPEAKER_00]: So the nerve root for L3 is coming out below L3.
[SPEAKER_00]: The nerve root for L2 is coming out below L2.
[SPEAKER_00]: And so a discarnation between L2 and L3 will get the L2 nerve root.
[SPEAKER_01]: All right, question six, 67-year-old male has undergone a thoracol abdominal aortic aneurysm repair.
[SPEAKER_01]: Shortly after the patient is brought to the ICU, they develop suspected anterior spinal artery syndrome, which of the following symptoms would be most consistent with this presentation.
[SPEAKER_01]: A, loss of motor function in the lower extremities, B, loss of proprioception in the lower extremities, or C, loss of vibratory sensation in the lower extremities.
[SPEAKER_00]: Yeah, so if you've seen this, you know that it's going to be motor, and usually actually it's proximal motor.
[SPEAKER_00]: So what we see is like thigh muscle weakness, leg flexion, so the ability to bring the thigh up towards the abdomen, that gets weak, usually first, and then of course it can spread from there.
[SPEAKER_00]: So it's going to be the motor function that is most consistent with this anterior spinal artery syndrome.
[SPEAKER_01]: Yeah, and we'll talk about mostly a section a little bit later and we'll get a little bit more of an organization of a spinal cord, but most of the motor tracks sort of run in that anterior area where it's the sensory tracks run in a more posterior area, which is why some of those are preserved.
[SPEAKER_00]: Yeah, and as you said, there's only one anterior spinal artery where there's paired posterior so you're kind of more at risk in that anterior part.
[SPEAKER_01]: Absolutely, seven, which of the following characteristics of the RASIC vertebrae making median thoracic epidural approach more difficult than in the longer region?
[SPEAKER_01]: Is it a, the bifin nature of the spina's process, be the curvature of the thoracic spine or see the orientation of the spina's process?
[SPEAKER_00]: So again, this is easy once you've done your rotation in OB and the stage because you will have or any, I guess, doesn't have to be in the stage, but where you're doing a lot of epidurals, where you're looking at the models, and then when you, of course, do thoracic surgery and you're doing those thoracic epidurals because it is, in fact, the orientation of the spines processes that make it really difficult to get in a median approach, not impossible, but very difficult in the thoracic region.
[SPEAKER_00]: You can get rid of a because the bifid spines
[SPEAKER_00]: And so that doesn't apply, and then it's not the curvature, it's the orientation of those minus processes that is a problem.
[SPEAKER_01]: Yeah, the curvature of the spine is actually helpful in the thoracic, whereas it can sometimes be a hindrance in the lumbar, which is why we need to get people sort of round out their back and slouch in a way if they typically don't.
[SPEAKER_00]: Yep, absolutely.
[SPEAKER_01]: 8.
[SPEAKER_01]: The archiviral, redicularist magna, most often originates from the aorta in the region of A, T6 to T8, B, T9 to T12, or C, L1 to L3.
[SPEAKER_00]: Yeah, so this is that artery of a damp quits, which I'm sure I'm pronouncing wrong, and that is something you just have to memorize that it's going to be between T9 and T12.
[SPEAKER_00]: And they're not going to ask you it this way, right?
[SPEAKER_00]: They're not going to say which level is it, probably.
[SPEAKER_00]: But what they might give you is a scenario where you're having a
[SPEAKER_00]: eight NT12 and they're going to ask what your concerns are or they may give you a different different levels of where the graph might be and ask what you might be concerned about.
[SPEAKER_00]: So just knowing that general area is important.
[SPEAKER_00]: It doesn't have to be by the way, that's just the most common.
[SPEAKER_01]: All right.
[SPEAKER_01]: Are you ready to move on to the next section?
[SPEAKER_00]: Let's do it.
[SPEAKER_01]: Okay, we'll talk about the meninges next.
[SPEAKER_01]: We'll hit a few basics and then a couple of key concepts.
[SPEAKER_01]: The meninges are a protective layer around the brain and the spinal cord.
[SPEAKER_01]: They're made of three layers.
[SPEAKER_01]: The outer most is the dura.
[SPEAKER_01]: That split into a periastial layer.
[SPEAKER_01]: That's close to the bone and connected to the sutures at the bone and a meningial layer.
[SPEAKER_01]: That's closest to the brain tissue.
[SPEAKER_01]: Under Vodera is there rackinally, that's said a vascular layer involved in cerebral spinal fluid metabolism and it's sort of tracks wherever Vodera goes.
[SPEAKER_01]: And then the final layer is the PO, which is the final layer that it hears directly to the brain and spinal cord.
[SPEAKER_01]: So this is Vodera Vodera's sort of follow all of the grooves.
[SPEAKER_01]: of the brain, unlike the prior two.
[SPEAKER_01]: Two more key concepts to add in.
[SPEAKER_01]: Key concepts six, because Fedora is tightly attached to the cranium and sutures, epidural bleeds are restricted in these areas, and therefore appear convex on imaging.
[SPEAKER_01]: Subdural hematomas are not restricted by these sutures, and therefore have a concave shape.
[SPEAKER_01]: In key concept 7, the spinal sub-dural space is poorly demarcated potential space between the dura and the arachnowing membranes.
[SPEAKER_01]: In comparison to the epidural space, which is well-defined potential space between the dura and the ligament and flavour.
[SPEAKER_01]: The Dural Sheaf covers most of the roots for a small distance, even after they've exited the spinal cord.
[SPEAKER_01]: That's important when you think about blocks that may be placed in the fact that you can risk sub-rack noise, infiltration of vocal anesthetic that way.
[SPEAKER_01]: And the Dural sack also extends down to this sacral vertebrae beyond the end of a spinal cord.
[SPEAKER_01]: All right, question nine.
[SPEAKER_01]: A 24-year-old patient suffers a witness traumatic fall after a brief lucid period.
[SPEAKER_01]: He loses consciousness and is brought to the emergency department.
[SPEAKER_01]: A non-contrast head CT for suspected intracranial hemorrhage would most likely reveal which of the following findings.
[SPEAKER_01]: A, a hyperlacholic convex lesion, B, a hyperlacholic concave lesion, or C, a hyperlacholic convex lesion.
[SPEAKER_00]: Right, so you've got to put a variety of pieces of knowledge together here.
[SPEAKER_00]: First, hopefully you know that in a cute bleed is going to appear hyper-acrylic on head CT.
[SPEAKER_00]: So you can get rid of hyper-acrylic right off the bat.
[SPEAKER_00]: And then you are going to have to remember
[SPEAKER_00]: What you said earlier Tim about how these spaces work and you're also going to have to remember what this description is so this is kind of I remember even before I was a doctor.
[SPEAKER_00]: I remember this kind of thinking well This is the scary thing right the epidural hematoma where you you're fine at first and then later you you know You either
[SPEAKER_00]: are fine, then you'll all of a sudden start vomiting and lose consciousness or something like that or you are fine and then you, this is why you don't want a kid to go to sleep right after they've been hit in the head because then you might not know if they deteriorate because you're afraid of that epidural hematoma.
[SPEAKER_00]: Subdural hematomas usually are slower and accumulate over time.
[SPEAKER_00]: So it's that acute injury where you are fine at first and then lose consciousness.
[SPEAKER_00]: So that's what's described here, brief lucid period.
[SPEAKER_00]: So you know we're talking
[SPEAKER_00]: And as you said, these are going to form convex lesions on imaging.
[SPEAKER_00]: So you're going to have C, be the right answer.
[SPEAKER_00]: It's hyper-acolic because it's a cube blood and it's a convex lesion because it's in the epidural space.
[SPEAKER_01]: Yeah, that was wonderful.
[SPEAKER_01]: I think you hit all of the sort of key points that you could, for what you need to answer this question correctly or other questions like it.
[SPEAKER_01]: I think the only thing that we didn't state yet is that your epidural bleeds tend to be arterial, your sub-dural bleeds tend to be venous, but now you have all the pieces to answer any version of that question.
[SPEAKER_01]: Ten, which of the following structures are likely traversed during paramidian thoracic epidural placement?
[SPEAKER_01]: A, skin, perisfinus muscle, inner sphinus ligament.
[SPEAKER_01]: B, skin, perisfinus muscle ligament inflate them.
[SPEAKER_01]: C, skin, inner sphinus ligament, inner ligament inflate them.
[SPEAKER_00]: Yeah, so this is important to, again, read the stem carefully.
[SPEAKER_00]: It is a paramidian, not a medial approach.
[SPEAKER_00]: And so hopefully you can just kind of think through that if you're coming from the side, you're not going between two spinous processes until you're not going to hit the,
[SPEAKER_00]: interspinus ligament.
[SPEAKER_00]: And so, you can get rid of A, and then that actually, with that, you can get rid of A, and see, and that gives you the right answer.
[SPEAKER_00]: And so, even if you didn't remember exactly, you should be able to figure that out.
[SPEAKER_00]: Even just, even if you didn't know what it was, just interspinus ligament seems like it's probably in between two of them, and you're coming from the side, so you're going kind of around that.
[SPEAKER_00]: So, the answer is B, you'll go through skin, of course, and then the pair of spine is muscle, and then the ligament
[SPEAKER_01]: Absolutely.
[SPEAKER_01]: As you do these questions, and you'll get one of these on every exam you take.
[SPEAKER_01]: Pay attention to whether it's epidural or spinal, pay attention to whether it's a pair of median or median.
[SPEAKER_01]: Question 11, which of the following structures represent the correct order in which they are traversed during the median lumber or spinal anesthesia placement?
[SPEAKER_01]: A, super-spinous ligament, ligament and flavum, dura epidurals face.
[SPEAKER_01]: B, inner-spinous ligament, super-spinous ligament, ligament and flavum dura, or C, inner-spinous ligament, ligament and flavum dura, or act-knowing matter.
[SPEAKER_00]: So, as you said, read carefully, this is a spinal, okay?
[SPEAKER_00]: So, it's not an epidural, it's a spinal, and it's median in the lumbar region, okay?
[SPEAKER_00]: So, we know that now we are going to go through that interspinus ligament, and
[SPEAKER_00]: beyond that you really have to know kind of the order, but if you think about it, if it's a spinal, the last thing you're going to go through is the Urachnoid Mata, right?
[SPEAKER_00]: Because you're going to get into the sub- Urachnoid space.
[SPEAKER_00]: So actually, if you just think about that, you can get the right answer here, because that is the last, the only one of them ends in that.
[SPEAKER_00]: But even without that, if you think about it, skin is not on here, those skin, of course, would be the first thing.
[SPEAKER_00]: And then you're going to go through the inner spinous ligament, then the ligament to play them, then the dura, and then the erectoid body to get into the sub-rack notes base.
[SPEAKER_00]: So C is the right answer.
[SPEAKER_01]: It is.
[SPEAKER_01]: And B has all of the right things in it.
[SPEAKER_01]: It might be missing some like skin and that raccoonly matter, but the order is wrong.
[SPEAKER_01]: Superspinus ligament.
[SPEAKER_01]: You hit before the inrespinus.
[SPEAKER_01]: That's the most posterior ligament in the spine.
[SPEAKER_01]: Great.
[SPEAKER_01]: And lastly, we need to cover some of the autonomic nervous system.
[SPEAKER_01]: A lot of the questions on the autonomic nervous system are a physiology.
[SPEAKER_01]: We'll leave those for another day, but there's a few things we should shore up in terms of anatomy.
[SPEAKER_01]: And since we're talking anatomy today, we'll do those.
[SPEAKER_01]: To concept 8, the parasynthetic nervous system, which is entirely colon, or as I said, I know, is composed of long pre-anglionic axons, which originate from cell bodies located in the brainstem, specifically cranial nerves, 3, 7, 9, and 10, and sacrosygnence, as to do S4.
[SPEAKER_01]: Those axons synapse and ganglia near the target organ, and therefore the post-ganglionic fibers are short since they're close to that target organ.
[SPEAKER_01]: key concept 10, the sympathetic nervous system in contrast originates in the spinal cord between T1 to L2 or 3, and the pre-gagly ionic axons are short, and synapsing, ganglia, close to the spinal cord, such as the sympathetic chain, which gives rise to long post-gagly ionic fibers that synapsent target organs.
[SPEAKER_01]: The sympathetic and parasympathetic nervous systems in their organization are almost mirror images of each other.
[SPEAKER_01]: The cell bodies in different places, in the pre-it and post-gagling, the fiber lengths are opposite lengths.
[SPEAKER_01]: T-concept 11.
[SPEAKER_01]: The carotid bodies or carotid receptors increase neuronal activity in response to decreases in PAO2.
[SPEAKER_01]: They signal via cranial nerve nine, fossil fossil, fossil for angeo, to stimulate increased ventilatory drive.
[SPEAKER_01]: The aortic bodies also detected decrease in PAO2, but their effect is mediated by cranial nerve 10 at the vagus.
[SPEAKER_01]: and results in beta-cardia, hypertension, bronchol constriction, and steroid release from the internal limits.
[SPEAKER_01]: And then the cradid sinuses are barrier receptors, not tumor receptors.
[SPEAKER_01]: They're at the base of the internal cradid arteries, that signal via also the glossal pharyngeal, see an cranial nerve nine, to modulate sympathetic to her.
[SPEAKER_01]: Those three, I find, get lumped together very quickly.
[SPEAKER_01]: They're testing, if you remember the difference, between cradid bodies, aortic bodies, and cradid sinuses.
[SPEAKER_01]: And the last key concept for the day will be key concept 12, no seception, which is a transmission of painful stimulus from the periphery to the central nervous system.
[SPEAKER_01]: And it occurs during it, three neuron pathway you need to know.
[SPEAKER_01]: The first neuron cell body is in the dorsal root gang then.
[SPEAKER_01]: We talked earlier about how it's sort of in the posterior portion of a spinal cord.
[SPEAKER_01]: Those lie in the vertebral for amenity, spinal level.
[SPEAKER_01]: The neuron has an axon that splits
[SPEAKER_01]: and extends from the periphery to the dorsal horn of spinal cord.
[SPEAKER_01]: So it's kind of unique that the axon goes in two different directions in the cell bodies in the middle.
[SPEAKER_01]: The dorsal horn axon, the synapses on the second order cell.
[SPEAKER_01]: That sells axon crosses the midline in a sense in the controversial lateral spinal thalamus tract of the phallimus, where it synapses on a third-order neuron that projects to the post-central gyros.
[SPEAKER_01]: So you have a receptor in the periphery.
[SPEAKER_01]: That cell body of the axon that picks up that signal is in the dorsal root ganglion.
[SPEAKER_01]: It sends a little more axon to the spinal cord.
[SPEAKER_01]: You synapse, you cross, you go up to the phallimus, you go to the somatosensory area.
[SPEAKER_01]: Okay.
[SPEAKER_01]: Question 12, which of a following most accurately describes the organization of a Paris empathetic nervous system?
[SPEAKER_01]: A, short pre-gang dynamic axons, long post-gang dynamic axons, B, long pre-gang dynamic axons, long post-gang dynamic axons, or C, long pre-gang dynamic axons and short post-gang dynamic axons.
[SPEAKER_00]: Yeah, so you just went over this.
[SPEAKER_00]: I don't have a great way to remember it.
[SPEAKER_00]: If you remember the anatomy, like you said, the parasympathetic nervous system, which we were talking about, has synapses near the organs.
[SPEAKER_00]: So these long, pre-gankly-onic axons, and then short-post-gankly-onic axons, because you're already near the organs.
[SPEAKER_00]: So if you remember that, then you know the answer here is C.
[SPEAKER_00]: B doesn't exist.
[SPEAKER_00]: There's no long long, and then A is the sympathetic nervous system.
[SPEAKER_00]: Short then long.
[SPEAKER_00]: And I guess you could try to remember sympathetic starts with shorts, starts with S, so short sympathetic is the first part that might help you.
[SPEAKER_01]: Yeah, and for what it's worth for me, it's easier to remember the sympathetic system because I think we all remember the sympathetic chain and we know that it's a right mix of the virtually broad bodies.
[SPEAKER_01]: So if you know that those cell bodies originally in the spinal cord and don't go far, you know the sympathetic has a short pre-game dynamic.
[SPEAKER_01]: And if you know that both have a long and a short portion, you can reason out everything else from there.
[SPEAKER_01]: Question 13, soon after emergence and exhibition from general anesthesia for a lower extremity orthopedic procedure, a patient becomes psychotic.
[SPEAKER_01]: The reading comes rapid, which is most likely mediated by activity of witch area, a crowded bodies, be crowded sentences or see aerobic bodies.
[SPEAKER_00]: Yeah, and this is tricky.
[SPEAKER_00]: So hopefully you can remember that the crowded signess is a barrel receptor.
[SPEAKER_00]: So it deals with pressure.
[SPEAKER_00]: And so you can get rid of that.
[SPEAKER_00]: The crowded body is a chemo receptor.
[SPEAKER_00]: So it does deal with things like pH.
[SPEAKER_00]: hypoxia hybrocarbia.
[SPEAKER_00]: And so you can remember that by CBC, the order of CBC, the blood test, so carotid body chemical CBC.
[SPEAKER_00]: But the tricky part is that the aortic bodies also are chemo receptors, as you said.
[SPEAKER_00]: And so what you have to remember here is that
[SPEAKER_00]: the the aortic bodies as you went over earlier, Tim have a different effect, which is that their effect is break-a-cardia hypertension, rock-o-constriction steroid release.
[SPEAKER_00]: And it is the corroded bodies that go through cranial nerve nine and have increased respiratory drive.
[SPEAKER_00]: So you have to remember the corroded body is that chemo receptor that increases respiratory drive and that's why it's the right answer here.
[SPEAKER_01]: perfect.
[SPEAKER_01]: And our last question for the day, 14, signals passing through the Dorsal Reganglia most likely originate in which of a following.
[SPEAKER_01]: A, peripheral nosicethers, B, the Spinophalamic Tract, or C, the pre-moral cortex.
[SPEAKER_00]: great and so signals passing through the dose organically where do they originate and that that's key that word originate where they starting so you know that these are pain fibers and so they are going to need to originate peripherally in no receptors on their way up to the brain so peripheral noes receptors that's the right answer choice a
[SPEAKER_00]: they're not going to originate in the brain because they're traveling to the brain right you you had these are the ascending pathways and similarly the spinal flammic tract they need to start somewhere perfectly and then pass through on their way up perfect and if you ever get confused in some of these tracks remember that they're often named for the direction of travel so this final dynamic tract is spinal signals going to the phalanis so it's a peripheral
[SPEAKER_00]: Yeah, although, right, and then that is key, though, that we are talking about a somatic we are talking about somatic signals, right?
[SPEAKER_00]: So they are going up, but they can't start in the middle.
[SPEAKER_00]: They have to start peripherally.
[SPEAKER_00]: So that's why it's got to be the no-sacenters.
[SPEAKER_00]: Right.
[SPEAKER_00]: All right, fabulous.
[SPEAKER_00]: Let's turn to the part of our show where we make random recommendations, Tim.
[SPEAKER_00]: What would you recommend the audience check out for fun these days?
[SPEAKER_01]: A board game that also has a good app on the phone called Shards of Infinity.
[SPEAKER_01]: If I remember who recommended it to me back in the days or percentage reduce me to it, I would.
[SPEAKER_01]: I don't remember.
[SPEAKER_01]: It's a deck building game where you, you don't have to buy more cards with it, you buy the one thing, but in each game you build sort of a deck that you play with and you try
[SPEAKER_01]: beat your opponents.
[SPEAKER_01]: It is infinitely playable.
[SPEAKER_01]: There's no one good strategy.
[SPEAKER_01]: The cards that show up on the table really change how each game is played.
[SPEAKER_01]: It's one of the games that I think I most often don't play for a little bit and have to pick right back up after a while.
[SPEAKER_00]: say again what it's called shards of infinity.
[SPEAKER_00]: Nice.
[SPEAKER_00]: Sounds awesome.
[SPEAKER_00]: All right.
[SPEAKER_00]: I'm going to recommend a new game from the New York Times called Crossplay.
[SPEAKER_00]: It's basically scrabble, but you, it's just like, I mean, it is scrabble, but I think they made slight changes to the board.
[SPEAKER_00]: It's just so that probably for comp guessing for copyright reasons, so that it wasn't exactly scrabble.
[SPEAKER_00]: But it's essentially scrabble and you can play either with a computer or you can play with a random opponent or you can play with friends and it's nice because you can just do it whenever you have a chance.
[SPEAKER_00]: So you take a turn and maybe you get busy and you come back to it a few hours later even the next day, you take another turn, there's no rush.
[SPEAKER_00]: And what I have found is that the app does a pretty good job of matching you up with people who are similarly skilled.
[SPEAKER_00]: And once it's seen you play a few games, so what I did is I played against the computer for several games and then it kind of got a feel for my skill level and then matched me up.
[SPEAKER_00]: So the games I've played against random people have been pretty close and that's a lot of fun.
[SPEAKER_00]: So check it out, cross play from the New York Times.
[SPEAKER_00]: All right, Tim, thanks so much for coming back and doing another keyword episode.
[SPEAKER_01]: Thanks so much, and I just sent you a friend invite on crossplay.
[SPEAKER_01]: So, it's on.
[SPEAKER_00]: Oh, it's on later.
[SPEAKER_00]: It's on now.
[SPEAKER_00]: Alright.
[SPEAKER_00]: All right, hopefully you got as much out of that as I did.
[SPEAKER_00]: That was really fantastic.
[SPEAKER_00]: Let us know what you thought.
[SPEAKER_00]: Go to the website,acrack.com where you can leave a comment.
[SPEAKER_00]: Others can learn from what you have to say.
[SPEAKER_00]: If you are a fan of the show, you can follow us.
[SPEAKER_00]: We're on Twitter.
[SPEAKER_00]: We are on Facebook.
[SPEAKER_00]: We are on Reddit.
[SPEAKER_00]: And we are an Instagram.
[SPEAKER_00]: I'm at Jay Wolpa on Twitter.
[SPEAKER_00]: And we're at Acrack Podcast.
[SPEAKER_00]: And you can find us on all those other platforms as well.
[SPEAKER_00]: If you are a fan of the show, please consider going to Apple Podcasts or wherever you get your podcasts and leaving a comment and a rating, it really helps others find the show.
[SPEAKER_00]: If you'd like to support the making of the show, please consider going to patreon.com-acc where you can become a patron of the show.
[SPEAKER_00]: Even if it's just a dollar or two that you pledge, it makes a big difference and we really appreciate it.
[SPEAKER_00]: You can also make donations anytime by going to PayPal.me-slash-acrack or looking up J.Wallpa on Venmo.
[SPEAKER_00]: Thank you so much to those who have already made donations and become patrons, we really appreciate it.
[SPEAKER_00]: Thanks as always to our fantastic acrack crew.
[SPEAKER_00]: Sonya Aminat is our tech lead, Taylor Duggen, William Mao, and Rachel Furman are our production assistants and social media managers.
[SPEAKER_00]: Thanks so much for all you do.
[SPEAKER_00]: Our original ACRAG Music is by Dr. Dennis Quow.
[SPEAKER_00]: You can check out his website at studybusicproject.com.
[SPEAKER_00]: All right, that is it for today.
[SPEAKER_00]: For the ACRAG podcast, I'm Jed Wolpa.
[SPEAKER_00]: Thanks for listening.
[SPEAKER_00]: Remember what you're doing out there every day is really important and valued.