in today's video we are going to be talking about anatomy of cranial nerves this video is sponsored by my friend jennifer jennifer is a current medical student with a really awesome company she has a company called jennifer's medical art and what she does is she creates these anatomy worksheets and these coloring pages that are also based on anatomy so that you can use these worksheets and use these coloring pages to learn material that you need to know for medical school for usmle and comlex board exams and to be honest guys this isn't just for medical students any graduate health professional any undergraduate health professional even people down in high school and middle school anybody who's tackling the concept of anatomy can really benefit from gen med art she's got these really awesome coloring books and worksheets and you guys have heard me say it before the way to learn is to actively challenge your brain to engage in a task so for example when you're sitting here listening to me talk that's a very passive activity you're not fully engaged but when you're sitting down filling out a worksheet or coloring in an anatomy coloring page you're actively using visual learning and you're combining the science behind visual learning seeing something in front of you with the active process of really encoding those memories into your brain and those are just some of the reasons why gen med art is an excellent choice for supplementing your studying this is fun this isn't boring and if you use her worksheets or your coloring books you're just frankly going to do better in anatomy she also has some really cool unique doctors pins that you can pin up to the lapel on your white coat if you are interested but guys gen med art is an awesome company so check her out jenmedart.com that's www.genmedart.com you can also find her at genmed art on facebook instagram tick tock and youtube i want to paint an overview of what this video is going to include so that you can sort of have a table of contents in your brain the first part that i'm going to talk about is the origin of the cranial nerves that is to say which part of the brain do the cranial nerves come from the next part of the video after that we'll be talking about the foramen or the foramina through which the different cranial nerves pass and then we will conclude the video by doing some practice questions where you have to actually label the cranial nerves on like a gross anatomical cadaver brain and a lot of this stuff is very high yield for usmle and complex but i'm also paying very close attention to things that you would actually have to know if you were taking a medical school or other graduate health school exam so with that said let's start with the origin of the different cranial nerves and before you can go through the origin of the cranial nerves it's really important to understand the anatomy of the brain statement that anatomy is what you see here on this slide and i've got two pretty good pictures for you the one on the left is obviously labeled and the one on the right is unlabeled if you wanted to pause the video and you know test yourself to see if you understand the anatomy of the brain stem but when it comes to the anatomy of the brain stem what's really important are a couple things going downward you you start at the top with the midbrain then you reach the pons and then you reach the medulla and those three parts of the brain stem are where all of these cranial nerves with the exception of two of them will come from the other really important thing that i wanted to highlight especially in this picture that you see on the left here is the olive so the olive is this bumpy little protuberance that sits on the medulla and the olive will be very important for figuring out where certain cranial nerves come from specific to the medullary area and this will make more sense in just a bit when we get to that part of the lecture but i want you to really pay attention to what that olive looks like because some cranial nerves will pass in front of it and some will pass behind it and it's only that little structure that olive that will help you figure out what cranial nerve you're looking at so if you're weak on your brain stem anatomy i would encourage you to pause the video now digest this a little bit with you know paying very special attention to mid-brain ponds and medulla and then specifically in the medulla the olive once you're comfortable with the anatomy of the brain stem we can then start to have a conversation about cranial nerve origins so this picture is an overview of all 12 of the cranial nerves we're going to go through these one at a time and i'm going to point out where they are originating from because that's a very high yield thing that you need to understand the first two cranial nerves are cranial nerve one which is the olfactory nerve and cranial nerve two which is the optic nerve and these are the two exceptions to the rule so by and large all of the cranial nerves will originate from different parts of the brain stem except for these guys so cranial nerve one and cranial nerve two actually originate from the cerebrum and i've drawn in the red arrow pointing to where the connection is being made from the base or the origin of the cranial nerves and as you can see in both cases here it's originating from the cerebrum so this is not coming from the brain stem the fact that this is an exception to that rule is what makes these two cranial nerves in particular very very high yield if they're going to give you an anatomy question about origin of cranial nerves so remember the first two cranial nerves one and two come from the cerebrum not the brain stem and again the fact that that's an exception makes this really high yield now as i just said after you've gotten through one and two the remaining cranial nerves so cranial nerves three through twelve they all come from various parts of the brain stem from so from here on out we're talking about brain stem origins so let's move on to cranial nerve three the oculomotor nerve so i'm pointing to the oculomotor nerve which is shown here in yellow and the oculomotor nerve is originating from the midbrain pontine junction so if you look very specifically where my red arrow is pointing it is at the area where the midbrain and the pons meet so the midbrain pontine junction is where cranial nerve 3 comes from moving on to cranial nerve four the trochlear nerve which is shown here in that sort of pinkish color the trochlear nerve comes from the midbrain so you can see the red arrow is pointing to an area where that nerve kind of wraps down into the midbrain and what's really how yields know about the trochlear nerve is that for whatever reason this cranial nerve has the longest intracranial length so keep that in mind uh the trochlear nerve is the longest intracranial length cranial nerve five is the world famous trigeminal nerve which is shown here in that kind of bluish color the trigeminal nerve has three different distributing nerves within it which are known as v1 v2 and v3 v for the roman numeral five since this is cranial nerve five and the trigeminal nerve originates from the pons and i think that when you look at this picture that's perhaps the clearest uh origin just simply looking at the picture you see that that big fat meaty trigeminal nerve comes right from that pons very clear um and the trigeminal nerve does tend to be really high yield because it's so diffusely involved in so many different processes that it's it's such a high yield nerve that i would definitely know that the trigeminal nerve comes from the pons now we're going to talk about three cranial nerves together so we've got cranial nerve 6 which is the abducens nerve we have cranial nerve 7 which is the facial nerve and cranial nerve 8 which is the vestibulocochlear nerve and all of these nerves are somewhat around each other anatomically speaking and they're grouped together because they all have the same origin so they're all coming from the pontine medullary junction so in other words the area where the pons and the medulla come together and you're not really on the ponds you're not really on the medulla you're really at that junction where they meet and if you look at my picture what i did was i put a black circle or a black ring with a little bit of a red shadow to it around the origin of all three of these nerves and if i go back just one slide and remove that circle you can sort of see that these nerves are all coming from that junction so the the purple nerve that's cranial nerve six the green one that's seven and the the bright pink one that's cranial nerve eight and as you see they're all coming from the same area the pontine medullary junction now just like all three of these nerves are grouped we're also going to talk about the last four they're all grouped as well you've got cranial nerve nine which is the glossopharyngeal nerve cranial nerve 10 that's your vagus nerve cranial nerve 11 is the accessory nerve and cranial nerve 12 is the hypoglossal nerve and this is what i was talking about a bit earlier in the video with having to know about the olive so if you look at these nerves you can separate them based on whether they're in front of the olive or behind the olive and cranial nerve 9 10 and 11 they all come out of the medulla posterior to the olive so if you look on this diagram and you find that little olive protuberance which is just behind or deep to the hypoglossal nerve on this image you see that cranial nerve 9 10 and 11 originate from the medulla but behind that olive or posterior to it and then if you look on the left side of this image cranial nerve 12 your hypoglossal nerve that comes out of the medulla but it's anterior to or in front of the olive so on the image you can't fully see the bump of the olive because cranial nerve 12 is on top of it or blocking it but just behind that little yellow web which is the hypoglossal nerve that's where your olive is so again whether these nerves are coming out of the medulla anterior to or posterior to that little bump is going to determine which cranial nerve they are if you have to select them in a diagram or pin them on a cadaver etc etc so that's all 12 of the cranial nerves and if i was going to give you a beautiful high-yield sexy dirty medicine table to summarize here is what i would show you again i'm not going to read this to you but pause the video if you would like to review this and go through the origins of your various cranial nerves okay so part one of the video is down you now understand the origins of the cranial nerves again particularly high yield especially in the first two years of medical school when you're taking exams and getting used to the different types of anatomy questions that will come up what's probably just as high yield in the first two years of medical school and even way way way more high yield for usmle and comlex are the different foramina that these cranial nerves were passed will pass through so a foramen is just a hole or a canal through which some anatomical part will pass and on the base of the skull we've got tons of uh little holes in little canals so you have tons of foramina and you can see them on this diagram and for whatever reason for anatomy questions it's really high yield to know which cranial nerve passes through which hole and that's what we're going to do now so i'm going to use this diagram which is already labeled as to what all of the different holes are and i'm going to go through the cranial nerves one at a time showing you which one passes through which hole so we'll start of course with cranial nerve one the olfactory nerve that passes through the cribriform plate cranial nerve two the optic nerve that passes through the optic canal and that's kind of easy to remember because it's the optic nerve and it goes through the optic canal cranial nerve 3 4 and v 1 and 6 all go through the superior orbital fissure now i'm going to pause for a second as you'll see talking about the foramina through which the cranial nerves pass it's not you can't just say the trigeminal nerve goes through the superior orbital fissure the correct and more correct way to say it is that the v1 distribution of the trigeminal nerve goes through the superior orbital fissure and of course v2 and v3 the other distributions of the trigeminal nerve will also go through other holes at the base of the skull and we'll talk about those in just a second but superior orbital fissure is 3 4 v1 and 6. now v2 the second distribution of the trigeminal nerve that's going to pass through the foramen rotundum shown here on the left side of this image cranial nerve v3 the third distribution of the trigeminal nerve that's going to pass through the foramen ovale okay so at this point we've talked about where all three parts of the trigeminal nerve v1 v2 and v3 which foramina they're passing through and again just to really summarize and make your brain hear it for the fourth time v1 goes to the superior orbital fissure v2 goes through the foramen rotundum and v3 goes through the foramen o valley now let's talk about cranial nerve seven and eight so facial and vestibulocochlear nerve will both go through the acoustic meatus cranial nerve 9 10 and 11 the glossopharyngeal the vagus and the accessory will all go through the jugular foramen and then the hypoglossal nerve which is cranial nerve 12 will go through the hypoglossal canal which is also quite easy to memorize because it's the hypoglossal nerve going through the hypoglossal canal so i know what you're thinking i need a sexy dirty medicine table and here you are this is your summary of all of the cranial nerves and the foramen or the foramina if you want to pluralize it through which they pass and i want to pause on this slide for a second to just point out a couple things and maybe give you a mnemonic or two so regarding the trigeminal nerve v1 v2 and v3 the way that you can memorize them to remember the order and the the foramina through which they pass is by saying fro fro fro so the trigeminal throat the first one is the fischer the second one is the rotundum and the third one is the o valley so fro fischer rotundum o valley that always helped me memorize and remember the order and the the foramina through which the trigeminal distributions will pass some some other things to remember is that if you look at cranial nerve three four and six they're all going through the superior orbital fissure in addition to v1 which we just talked about and that's kind of easy to remember because cranial nerves three four and six are all involved in helping with movement of the eyeball and the name of the hull is the superior orbital fissure so you know it's around the eye because it has orbital in the name so all of the cranial nerves that control the movement of the eye are all going through the only foramina that has something to do with the eye in the name so kind of easy to remember vestibulocochlear nerve obviously involved in a lot of different processes regarding our ability to hear and therefore it goes through the internal acoustic meatus so the only uh the only name that has acoustic in it which should cue you into that it's got something to do with hearing obviously vestibulocochlear will pass through that foramen the other thing that i want to help you memorize are the cranial nerves that go through the jugular foramen so cranial nerve 9 10 and 11 glossopharyngeal vagus and accessory they're all going through the jugular foramen and the way that i always memorize that was by rewriting jugular foramen as jugular voramin and that g for glossopharyngeal v for vagus and a for accessory okay so that's all the most mostly high-yield information that you need to know regarding the different canals through which the cranial nerves are passing we've now concluded part two of the video and let's wrap up with part three and do a little rapid review practice question pin the cranial nerve anatomy style so first question identify the oculomotor nerve pause the video if you want some more time to think about it but your oculomotor nerve is right there where the orange arrow is pointing question two identify the optic nerve pause the video if you need more time and the optic nerve is right there where the orange arrow is pointing question three identify the abducens nerve pause the video if you would like more time and the abducens nerve is right there question four identify the olfactory nerve pause the video if you would like more time this is actually the easiest one i could have given you the olfactory nerve is that big tall one at the very top it's the first cranial nerve it's usually at the top of this underside image of the brain question five identify the facial nerve the facial nerve is right there where the orange arrow is pointing it's that very tiny nerve it's very very close to some other nerves around it so you really gotta study your anatomy to be able to differentiate between these but that's the facial nerve question six identify the hypoglossal nerve pause the video if you would like more time and the hypoglossal nerve is right there where the orange arrow is pointing remember the hypoglossal nerve is the one that comes out of the medulla but it's anterior to the olive so it's the one like closest to you when you look down on this image when you're looking at the medulla i hope that those anatomy questions were somewhat useful to you if you're a first-year medical student you're going to be ripping your hair out in anatomy lab trying to get these cranial nerves correct on the you know the questions where they make you identify what's pinned to what cranial nerve but it's very important to know on us emily and comlex they do occasionally show you diagrams that you need to pick like you know what what is this pointing to or what does a in the picture represent so anatomy is totally not off the table don't let anybody tell you that you don't need to know it because you absolutely do but again today's video was the cranial nerve anatomy i hope it was useful to you just to summarize what should you know from this video the origin of the cranial nerves the foramina through which the cranial nerves pass and then be able to tag or identify the different cranial nerves on a gross image or on a cadaver good luck