Transcript for:
Overview of the Peripheral Nervous System

peripheral nervous system what's the peripheral nervous system what does it consist perfect thank you everything put the spinal cord in the brain it's broken into what two types of nervous systematic is also known as what what voluntary in visceral is known as involuntary these are the nerves that allow for the central nervous system to receive all the information right how's it receiving information what's sending information what is sending information sensory receptors right sensory nerves those are all those are always going to go they're going to go dorsal right into this thing called the dorsal root okay and then the initiate action would also be what what kind of nerve is carrying the action Mot perfect so the general visceral motor division of the peripheral nervous system is also called also has autonomic system as well right so this is where we're actually going to get into how not how but where and what is working during this par sympathetic in sympathetic system okay so we have two different sides AER eer you guys have known this you guys know we've talked about it talked about sympathetic and parasympathetic that we're going to have autonomic lecture and we are going to specifically talk about this side okay they're specifically going to be there I excuse my coughing everyone in my family is sick at some point um organization we have sensory receptors what are sensory receptors doing what's their purpose to to to to to sense a change in s right nerves and gangl nerves Peron in the ganglia or clusters zonal cell bodies we know this this is again a repetition to remember motor endings we know what what happens between a motor ending and the next nerve what is that called what's the space between those two things the synaptic cff right and then so we have uh on each side of the synapse we have two nerves what are those two nerves called neur what's the first one aptic and the second one is okay so when they talk to each other they're talking to each other with what how a nerve ending is talking to normally a dend what's the other option OA right aosa contraction okay um trying to think of the other things need to know what are the things that go through the uh synaptic neurotransmitter perfect sometimes mying my wife loves structures so our peripheral sens receptors are going to initiate the signal from the sensory axons do they think do our sensory receptors think no what their Prime purpose is what to send to have whatever it's going to be let say that we put our hand on something that vibrates all it's doing is sending a signal that says vibrate and instantly our brain understands what it feels not instantly but very very close very fast okay we have different things classified into different different receptors are classified external receptors internal receptors and prop receptors you don't know You' SE you've now seen these words once external receptors would be sensitive to what type of changes external what would be internal okay and then Pro receptors we talked about which is going to be stretch receptors joint angle receptors uh telling us where our body is in space vestibular sensors things like that okay it's those are going to be classified as stimulus type in structure so whether they're going to be encapsulated or they're going to be free nering so let's talk about external receptors located near the body surfaces they monitor touch pressure pain and temperature what's really interesting is we actually have a s we have a receptor that's sensitive to pain but in my mind it's kind of hard for me to wrap my head around that because if we're if we have pain our brain is the one that understands pain right but then we have a receptor that's already there that is sensitive to pain right so it's got to be some sort of that's greater than just the regular stimulus that we usually feel right that's how I kind of that's how I'm wrapping my brain around it uh if if you have a better idea please let me know but it's like you know you can touch a warm surface you know you can even touch a hot surface like you can hold the cup your hot coffee and you be like oh that's hot but you don't have pain you just be like o that's hot right you put your hand in boiling water that's pain right and then you associate that pain with boiling water right so in my mind the pain that we feel with our external receptors is like the stimulus but on steroids are great does that make sense like it's whatever that is but above and beyond like we know that our receptors know that that's pain because it's too big of a stimulation whereas just temperature changes pressure changes uh uh touch changes you know that that won't be won't be triggered as pain you'll just see it does that make sense is that confusing probably I'm not trying to confuse you I'm just trying to get you to think about the pain receptors are something that's above and beyond what those regular sensors are feeling okay internal receptors they're going to receive stimulus from the internal viscer tell me what majority of these sensory signals would be would these be not pain temperaturea what visceral receptors are going to give us what type of information organ or known as visero okay so I I wasn't trying to trick you I understand that sometimes my questions have like a deeper meaning but essentially I want you to see if there's going to come from the inside or on an organ which is perfect that you said that if it's going to come on an organ we know that it has to be the visceral so what type of ination is it going to be it's going to be visceral sense okay if it's going to be internal it's going to tell us a little bit about the things that are probably going to be most mostly changes in our visceral for instance blood pressure stretching a smooth muscle changes in chemical concentration right we don't think of this consciously voluntarily right we don't say elevate blood pressure because if we could we could lower our blood pressure by Logic and then we would never have heart disease right we could change that as much easy so remember when it's coming from the visc whenever you see Vis I want you to think of something that's going to be involuntary almost all the time it's going to be involuntary okay then we have our proprioceptors which are located in skeletal muscles tendons joints ligaments right it's going to monitor the degre of change in the muscle strength stretch The Joint angle okay so what I mean by that is at all times we're receiving information it's keeping us weird way of saying it but it's keeping us aroused right it's keeping a weight we're always receiving sensory information but our brain is able to prioritize what is the most important thing right now you've sat down and most of you have your leg have you thought about the fact that your legs have been crossed for the last I don't know 10 minutes no why because we know where you are and we're good we have a move but once you move you're going to start to feel other things the chair you're going to feel the the the change in your muscle stretch okay so it's telling us where that body where your body part is in space why because our brain and our periphery are exclusive they talk to each other they communicate but one doesn't work without the other and the other one will tell the other what's going on does that make sense okay so we'll get into progress of a lot more but so we have mechan receptors that are respond to Mechanical forces touch pressure stretch vibration itch ches photo receptors respond to light this is going to be in our eye Noor is the har harmful stimuli that will result in pain okay so so remember the no receptors the pain receptors are going to be responding to a harmful stimuli that's going to be above and beyond what the stimuli have already Tes that make sense so let's say that again we can hold on to warm things we can hold even hold on to hot things but once it becomes painful once it becomes harmful we associate it as pain okay these are its own thing this is the hard one that kind of I have a hard timeing my rain Brown ring around even today this is kind of the way that I've accepted it in my my life okay free nerve ending what do they where are they they're located in skin bone internal organs and Joints they're abundant in our epithelia underlying our connected tissue and they're going to respond pain and tempure a lot of these nerve endings are going to respond to pain andure so these guys right so the majority of what's happening or where these nerves are are below the EP okay then they're going to get really really close to thein CC if you look at this are those three nerve endings pain and temperature are going to be really really close to the skin okay so every time you put your hand down on something you can tell if it's warm or cold right even if that's not what you're thinking it's sending that signal right if you touch it it's going to tell you what this is okay then we have two types of special nerve en epithelial tactile Merle discs that are sensitive to light and touch okay these guys right here light touch so here's the question I just told you temperature right but that's kind of touch at the same time right we can't we can't tell temperature without touch so a lot of what's happening right is we're going to feel when we put our hand down on something not only are we going to feel the pressure of what we've done what we've put our hand on but also the temperature of whatever that object is now when I say don't really feel we feel temperature Every Time We Touch something right the board is cold right this is warmer but the idea is is that even if we don't touch something and we feel cold wind we didn't touch it right but we felt it right those are those free nerve endes that are really really close to the skin but the light is tactile compx this is going to be in response to you touching something okay it responds to you touching or something touching you okay you put a shirt on the first the first part of the day you feel that shirt then you kind of forget that shirt is there until right question answer hair follicle receptors wrap around the hair follicle okay this makes sense what's this going to do it's going to sense hair movement when do we need this when do we want this would you say why would we need nerve ending to ground the hair fall what does that tell us what surrounded yes did anybody walk into somewhere and you feel like a feel like your hair stand on end like you walk in and you get really close to the board and you can feel your hair like that way like electr mechanical or Electro physiological forces and stuff like that I know not have class we're getting into but like you can feel that static electricity right uh let's say that let's say that you're in a fight ORF flying situation your hands your hair stands on it why would we want that to happen it gives us what more information right the hair stands on end so we can feel a slight breathe there's hopefully no one breathing down our necks or things like that but we can feel more info coming into our bodies right around our bodies it extends what's happening we can like you don't know you don't really feel wind unless the hair moves right so we have free nerve endings we have these tactile nerve endings and then a hair follicle okay each of these are going to be they're going to provide us with information at these different Mar so let's talk about encapsulated encapsulated nerve endings these have this is one single fiber right in this example it's going to be one single fiber I can have more right it could be this one then another and then another but essentially let's zoom in on a single one and it's going to have an encapsulated it's going to be encapsulated in connector tissue okay so this is going to be an important distinction because that capsule gives us a little bit more information what it's donees the capsule endings are going to be mechano we have four different tyes tactile l bulus corles or in our okay as you see we have these tacti ones we have our L we have our have these all these different ones that are going to have connective tissue around them and how we know what they're going to do is going to be the depth of which they are located in the skin right specifically in the Derm because what's the only nerve ending that's in the epidermis three nerve endings yep three nerve endings are the only ones in there then we have these tactile ones that are going to be attached to the base right where that zipper is where the two the epidermis and the uh dermal right come together is going to be right on top of there light touch so as we go through tactile or messenger CLE these are going to be spiral nerve endings surrounded by Schwan cells Schwan cells right are the the the stem cells that differentiate into this they help surround it they occur in the dermal pill of the hairless skin and they discriminate touch okay so not just like touch but they will discri discriminate what that feels like okay rough smooth uh bu that kind of stuff right like anybody go to like a hardware store and they put their fingers on different levels of sandpaper or am I just a weirdo okay so I do that um and you go go through the really rough stuff tell is rough and then then go to the other one it's going to be a lot like 600,000 grit is going to be really really but it's still going to have that kind of sandpapery feel but one's going to be way rougher than the other okay that's just lar cor puzzles single nerve endings surrounded by the layer of flatten Swan cells occur in the subcutaneous deep tissue of the skin and is sensitive to specifically deep pressure in vibration now we have talked about light touch discriminative touch and now deep touch as we go from epithelia we go from EP epithelia or epidermis further down it takes more and more pressure is more and more touch to stimulate these receptors free nerve endings anything that touches it it's going to send a signal okay as we go down the tactile if something has to touch you or you have to touch it okay then we go further down right we have our oops we have our L which is going to be even further down right this is going to be at the dermal propil right a way up close where they connect between the epidermis and the dermal dermis then we have our Lamar cor pusles it's going to be even deeper than that if it's going to those those capsules are going to straight or when touch happens they're going to change in shape and when that cap changes in shape that's the signal that gets sent to our central nervous system okay so if we Lamela right so our Lamela it's kind of vertical and has these spiral endings or spiral connective tissue so when we touch light touch okay a little bit discriminatory touch now we have deep touch okay deep pressure so we can place our hand on something you place your hand on something that it's not and then if you start to push down you get deeper and deeper because the the the capsule is starting to bend starting to change shape okay then we have our bulbas cor pule located in the dermis and again responds to deep pressure so tacti telling us Press light pressure discriminative touch vibration at low frequency right because low frequency vibration doesn't take a lot right it's not something that's really all that aggressive right but the more the more aggressive the vibration the more it's going to really feel down further down into our dermat okay now remember how how much how big is this it's not very big right like this section of epidermis and dermis it's not that much it's not that like it doesn't look like it's not this it's this thick but this is really really really small right so like the differences between deep touch and like regular touch it's not all that different but it's going to stimulate those receptors in a different okay so then our appropriate what are they going to do monitor stretch in the muscles ligaments and our tendons and we have three different types muscle spindles Gogi tendon organs and Joint kinesthetic receptors now these are super cool why because these are all going to tell our brains in our central nervous system what is happen Okay what is happening with the muscle so first we have our muscle spindle our muscle spindle is embeded in the parium between muscle FACS so this is an interfusal muscle fiber it's modified musle so this is not going to actually contract and they're not this big okay these are these are microscopic they are very very very very very very par okay they're not but for us to understand what they look like they look like this they have this like Spiral ending right that's going to send signals okay so what happen if this is in the muscle what type of stretch is it going to be sensitive to it's in the muscle what type of stretch is it going to be senstive what is stretching the muscle yes say it in the muscle it's going to be sensitive to the muscle stretch okay this is important why because these these muscle spindles can inhibit you guys know what what does inhibit stop slow down right keep back or whatever it's going to slow down inhibit stop signal going to that muscle if it stretch too much okay so what happens is is that as you fatigue and exercise or you're doing all of the biceps because they look great in the mirror and it's fun right you're going to do bicep after bicep after bicep and at some point you're going to fatigue or you're lifting too much your body your muscles are going to have these muscle spindles in the muscle that's saying we are stretched too much slow down it's going to actually stop the signal coming from the brain okay it's going to limit the amounts of signal coming from the brain so you don't have a catastrophe as a tear a complete tear of the muscle right this is basically a safety mechanism on top of knowing where your body is in space okay questions how do these work they're it's like a slinky right you guys know what slinkies are I had a great time in my childhood but now we don't know the slinky as you pull it apart the the spring elongates right same feel here as the muscle starts to become more tense it's Contracting right and these are going to start to pull and they're going to length it out and as they lengthen out they're going to send the signal to the spinal cord that says stop slow down it doesn't go to the brain yet it goes to the spinal cord first keep us from having a catastrophe of in our muscle will tell the brain we are going too hard and our muscle is too tun so we need to slow down or we need to stop doing what we're doing okay gendon orans gendon organs are going to be in our tendon okay located near the muscle tendonous joint or Junction excuse me the mechanical receptor what are they doing they're sensitive to tension we have two things that are going to be sensitive to tension muscle spindles T organs one is in the muscle and the other is in the tendon so why is this important because the muscle pulls on what the tendon and if the muscle is too taunt guess what the tendon is going to be to to taunt okay so if we have a lot of tension in this area we are going these gold orans are again going to send another signal to the SP that says inhibit slow down don't more activation because our brain again remember our brain is separated it communicates with but it only takes in what it wants right so this is going to actually go to the spinal cord these signals to say inhibit the activation you sent from the brain so that you don't tear your tendon right does this make sense then we finally have joint kinesthetic receptors hard to see in a picture but these are sensory nerve endings within the joint capsules if they're in a joint capsule what type of joint is that back so an sovial right they're mostly going to be in our synovial joint why because that's those are the ones with capses and so what is what's one very common popular s joint B in socket right so knees elbows shoulders hips okay so why are these important because the capsule changes shape with the different angle at which our body mov our body is station at all of you have basically most of you have bent knes right now right you feel that your body knows that so it stops talking about but as you're ex as you're walking you don't re recognize because your body body is already doing it knows where your body is in space and it knows not only the tension created in your muscle the tension created in your ligament or your tendon excuse me but also the joint space the capsule the the the changing of that capsule space gives us the angle at which our body is okay does that make sense so here's here's just the table you know I like table cranial nerve I'm not going to spend a lot of time on this a whole lecture of cranial nerves are you excited for that or scared no I hated this last semester well I have fun with it I don't know it's not fun I'm not going to lie to you it's hard okay um cranial nerves are peripheral okay they're organized in sensory and motor and some of them have both okay and the one primary primarily serve the head and neck except for notas like is 10 Vegas is named after like a vagabon why because it originates in the central nervous system right it originates in the cranium but it travels South to all of our Vis so the majority of the time when you say oh we have some sort of something when we talk about activation of the Vegas nerve it's usually going to be this majority of the time is going to be visible but we'll talk all about that I have them in in in flashcard type of of lecture so it'll be real real fun this is what they look like okay again can you imagine having a cic activity of 15 minutes real right but I'm going to try so let's talk about the spinal nerves we have 31 pairs on the right and left and they contain thousands of nerves right because remember nerves are just axons bundled together right there's a couple steps but there's just a long line of a axons going to and what do they do they connect to the spinal cord and they're name from the point of branching from the spinal C so what they did was nice they gave us eight cervical nerves that are going to be between C1 and C8 okay 12 thoracic wonderful right five pairs of five pairs of sacral and one pair of Cox one one Cox okay so that's the best part why because they're named for where they lead the spinal cord by the vertebra okay you already know this so this is kind of relatively easy question love it I don't know whether you're just too tired you don't want to listen to me anymore but we're just going to keep moving here's the dorsal Ro Gang This is the best part that's the part it's a top part connected to the spinal cord by the dorsal root in that vental root so all sensory signals from the periphery enter into the spinal cord through the dorsal root angle okay you all heard me say that where do all sensory signals enter the spinal cord no gangling every time 100% of the time okay if you are and you see sensory signal sensory signal originating somewhere in the periphery what is it going to do it's going to enter into the spinal cord through the dorsal roof gang okay this is why it's called dorsal roof gang because dorsal roof ganglia gangl has those cluster of neuronal cell bodies in the periphery that means outside of the central nervous system we're going to see a bulge and that's going to be where all the neuron or all the cell bodies are going to be the vent route is going to contain only motor fibers this is very organized for a specific reason all sense goes dorsal all motor goes vental all dorsal goes or all sensory goes dorsal all motor goes vent okay then we have these random things that tries to confuse they're called RMA Rami communicate okay these are going to be responsible for sending not only autonomic but also voluntary signals one way or the other Rami communicans at least specifically are going to be for the sympathetic nervous system so we have multiple different Ramis we'll talk about the Rami communicans when we get to autonomic but when we talk about how signal flows out of or goes into they're going to go through a specific R we'll talk so we see this this is d g what goes to the dorsal G sensory okay I love it love it love that you said it it's wonderful okay and it's going to go into the dorsal Horn of the spinal cord motor is going to go through the ventral root okay out and then depending on where it's going to go it's either going to go to the front or the limbs or it's going to go dorsal and they're going to be a specific round so let's talk about this a little bit more before we get into that we have doors gangan ventro rout what goes through the ventro RO motor 100% of the time all the time what goes through the dorsal rout sensory 100% of the time all the time now we have dorsal and vental Ramis now at so far we have what we have all sensory going through root we have all dorsal or we have all sens going through a route we have all motor going through a motor originates where in the central nervous system brain But Central Central Nervous System okay sensory signals originate where the periphery okay and they're known as air or E sensory known as a or e a motor signals are known as perfect now I'm going to confuse you we have two Ramis or Rami dorsal Ramis and our ventral Ramis the dorsal Ramis both of these Rami R are going to have both sensory and motor NES okay have both our roots are exclusive to one or the other dorsal Roots always going to be centor ventral route always going to be M but our ramas are going to have both now they're going to go in a specific way okay so the dorsal Rami is motor and sensory I don't know what you need to do bold it Circle it s it I don't know what you need to do I don't really care what you do but I need you to do something that highlights the fact that this dorsal Rami when it says Rami not root not horn R you have both motor and function and it's always going to go posterior dorsal will go posterior dorsal Rami goes posterior what does it have both motor and sensory nerves give you a second to play adjust because this is where we lose points on the exam because dorsal you see dorsal in your like dorsal root because it also starts with an AR dorsal root dorsal Ram dorsal root has exclusively what type of signals sensory all sensory nerves okay dorsal RI has how what types both motor and sensory and where does it go posterior now remember it's the sensory signal starts where I'm quing you guys today I know it's a Monday and you love it sensory signals start or originate where in the periphery they're going to travel in into the dorsal root into the dorsal into the central nervous system right yes and then but we need to know where is the posterior sensory signals coming from or how is it going into the central nervous system it's got to go through a Rami what Rami is that dorsal Rami and then how do it get to this final dorsal rout see I told you you you were on it you were PR I loved it dorsal Ramy is going to get sensory signals from the back okay and posterior trunk specifically essentially from here up okay is going to go always always always going to go through the dorsal Rami into the dorsal root into the dorsal Horn of the final C let's do it again sensy signals from our back it's going to go through what Rami dorsal Rami then through what rout dorsal why because it's all it's sensory signals so it's starting the periphery traveling through the rampus and we know that it's going to go through the root okay which route dorsal route why because it's sensory signal that's why I made such a big deal about knowing where it starts and where it's going to go how it's going to travel if you don't know that it's going to be really hard on the test because Ramis Roots ventral dorsal posterior an they're all going to get it's all going to get in your head and it's going to float around there and it's going to scare up okay so we did dorsal now what happens with ventral Rama it has both motor and sensory function where's it coming from answer your trunk limbs so if I give you an I give you a situation where you step on that Lego that destroyed our soul on you step on this Lego and it starts where where's the where's that signal starting from originating from the receptor where in the periphery it's going to travel up that sensory nerve into which Ram ventral right and then it's going to travel how into our spinal cord dorsal who said it's dorsal so who said that dorsal great dorsal route why yes all Central or all sensory signals go dorsal rout 100% of the time no matter where they originate no matter where they originate if there's sensory signal you right on your testal immediately okay why because it's starting in the periphery we know it's sensory so it has to go to the central nervous system it's a signal it's going to go through the dorsal rout now if it goes through our limbs or the anterior part of our body it is going to go through which Ram that's the only time it goes through the dorsal RIS is when posterior back right posterior of our trunk okay this make sense question yes yeah let's say I'm doing some sweet rhomboids right no one does rhomboids you can't see but we're doing RS okay and we feel the sense like we're stretch we're feeling that muscle stretch but we're saying to our brain we want to we want to contract that muscle is what type of what type of signal if you want to contract it it's what motor it's coming from don't say brain it's coming out of what root Central I spend so much time talking about dorsal so I'm glad you asked about ventral it's coming through the ventral root out of the spinal the ventral horn through the vental roots and then it's going where where going to the rid where are the rids in our back right in our back so if we're doing rhomboids we know that the motor nerve is going to exit out of the vental Horn of the spinal cord through the vental root going through which Gramma dorsal why dorsal because it's going to the poster the help no you're looking at me like I think I just got more confus so this is I told you I was G to confused I told you it was going to be confusing don't if the word has the word if if it's a Rami it's going to have both sensory and M okay if it's going to be a root it is going to be exclusively one or the other okay roots are exclusive to motor or scent Ram is going to be both sensory and motor the only difference of how things track is it where it's where that sense is going to or coming from okay okay remember know where the signals originating from if you know where the signal if it's originating Cally then it's what it's motor and if it's going to go somewhere it's got to go out of the vental rout already know then it's going to go if it's posterior dorsal if it's anterior or our limbs ventral ramp yes so if you get in the back of the head is that like is La different it's gonna have different types of signals yeah they're like it's from C1 don't worry about much easier examples on the exam I promise okay why because that's a cranial the head is a cranial from here down is is is spin only on question does this is this is this confusing is it is it less confusing than it thir who has more questions I know you guys have taken my class for I don't know 14 weeks so far 13 weeks you know when I sit here for 10 minutes on a slide probably super important um doesn't inner neuron play into this at all yeah it does but not where it comes out okay so where's the inter since you brought it up let's talk about it the inside the central nervous system yes in the spinal cord so great question let's talk about a nerve let's talk about a reflex poly synaptic reflex why not monosnap involes the poly syap does the mon doesn't right it goes from that place back to that place now if we have an inter neuron okay we have an Inon we have a signal we step I want to do the same example over and over again let's say oh this happened to me this weekend my toddler wanted to play with Legos so she wanted me on the floor next to her but I wasn't allowed to play I just allowed to sit there don't worry but so I laid down on a Lego you know what's harder to get off of a Lego is when you lay your entire weight on it and you can't roll off very well anyway so it's coming from the posterior side okay it's coming from the posterior side so it's going to go through the dorsal ramth in the dorsal root that's the signal then I've got to get off of that this is that withraw reflex right our main purpose is to take us away from this painful stimulation or a painful situation so this inner neuron is going to Signal all of the other musculature to get me crunched rolled and pushed that's a lot of muscles right so that inner neuron is going to send the motor nerve that out of which route ventral then it's going to go out to the ventral route now here's the difference I have motor neurons going to the back and I have motor neurons going to the front and have motur going to the limbs so we have motor nerves going through the dorsal back ventral right that's what's happening so in a reflex that inter neuron is going to play a really big role that help yeah so just in reflex use an in but like let's say you just wanted to live weights like it's already in your central nervous system so it's still going to use an in on because we're we haven't got there yet I love that you ask this question but we're going to send it from the brain and our left controls our right and our right controls are left the inner neuron is going to cross over and then we have a bunch of in neurons in our brain hereo so hump your brakes I love it but wait question I didn't just make it more if I did let's talk about nerve plexus okay nerve plexus or plexus eyes network of nerves vami branch and join with one other nerve with one another to so we have our cervical plexus located deep turn to our sto deep to our Stern cloid where's our sto this guy deep to that like right formed by the C1 through C4 okay this is sensory receptors sensory signals of the skin perticular region anterior neck and above and below the clav okay why because from our jaw up is a cran essentially everything underneath that is Z1 through Z4 okay the motor muscles of the neck or our frenic nerve this is formed the ventral r am i v Rami goes way anterior perfect yes okay inates the diaphragm or dier for okay what's really important about the diaphrag that we AKA if you C4 why it's the diaphragm you can't increase increase uh uh volume decrease pressure and allow for air to come in without the diaphragm right you end up suff don't recommend zero Stars brachial brachial located in the ne in exeler region okay these trunks here it's going to be C5 through T1 ventral Rami coming out why the ventral Rami here right it's going to our arms so it's going to break into three trunks it's going to split into two anterior and posterior divisions and then those six divisions converge into three cores you have a medial lateral and posterior then those five main of so what creates this rat Plex why is it ventral because of it's a limb it's a limb it breaks into all of these vental Rami okay are going to break into and they're going to form three trunks upper middle middle and lower those three trunks will combine to make three chords lateral medium those cords are going to then make one two 3 four five main nerves of the arm so three trun three five three chunks three cords five NES questions this is what it looks like on a Cav very very similar moving for your so let's talk about the upper extremity we have nerves of the posterior cord so we have axillary which is going to inate the deltoid the terce minor where is the deltoid okay terce minor harder to point to but like there right radial nerves inate the muscles of the poster upper Upper Limb and hand extensor posterior formal now remember back on like the fifth day that we were together I said learn your compartments remember me saying that hopefully just all this fun is SL back in but you remember I told you about the compartments the compartments are all interated by what a single nerve that single nerve is going to do all of the same actions all mus in that compartment are going to do the same action so all extenders are going to be extended all flexors are going to be flexed right so the radial inates the muscle to the posterior Upper Limb and hand extend extend so if they're on the posterior forearm what's that going to do okay posterior compartment of the forarm extends posterior compartment of the Upper Limb does what poor compartment of the Upper Limb anterior as well okay here's a different portion okay so we have our radial nerve right triceps triceps break your radialis is a little bit on the side then we have all of our exter all of our extensors extensor extensor extensor extensor we have an abductor random extens exens see that remember when I told you it doesn't matter if you know the names and the muscles for my class and you need to know the compartments you know that the posterior side of the of the arm is going to extend you don't need to know all any of these right you just need to know what's going to extend so nerve of the medial cord we have our deep hand muscles flexor digitorum flexor car three nerve of the lateral core muscular cutaneous interat upper anterior arm upper anterior AR arm so that's going to do whatx right no one says Flex on them and then EXT right everyone Flex it right the medial lateral cord Med inates the Deep hand Muses and fleers of the hand so we have AER it's going to flex then we have our lateral cord muscular cutaneous Flex okay medial lateral cords interv deep hand muscles and flexes the hand right so we have Flex Flex Flex great right so you know the other two are going to do extensors because they go to what compartment the posterior compartments so here's you I'm proba you're probably thinking how in the f is you g to ask a question about this it's going to be something along the line the blank nerve will inate the extend inate these muscles that lead to right because we're this is not a muscular Muscular skeletal exam this is a nerve here so you need to know the nerves and then knowing the compartment makes it good enough remember okay are we good lumbar Plex rises from L1 through L4 smaller branches inate the abdominal wall and the soaz muscle we have main branches we have Boral which is going to inate the anterior thigh muscle and the operator is going to inate the U so femoral nerve is going to inate the the anterior thigh which is what the Ben KNE extend the knee extend the lower leg okay contraction of the quadriceps are going to extend the lower leg okay what you thinking is the hip we're not talking about the hip sacral plexus arises from L4 through S1 often considered one with the lumbar plexus but so we can call this a lumbar sacral plexus but I need you to know that the sacral plexus is going to be a lot more south or inferior it's going to be around L4 through S or L4 through S2 okay SA or S plexus is going to have the sciatic nerve how many of you have heard something about the sciatic nerve that sciatic nerve has two nerves in one sheath usually when you have two things in one thing usually doesn't go well right the sciatic nerve have tial nerve which going to inate most of the posterior lower Lim muscle skin on the foot and leg right so what do that mean it's on the posterior side so it's going to do what your ankle planer Flex right a planter Flex common fibular nerve is going to inate the anterior lateral leg muscles divides into two Branch are superior or superficial fibular nerve and a deep FIB okay pent nerve is going to inate our muscles of the parum right remember the panum that we talked about that really cool diamond shaped thing reproductive system when the superior inferior glal musle or nerve are going to inate shockingly the Glu muscles the glal muscles do what to our hip you said it the first time be extend you're so close so close Okay question so we for moroner okay anterior side observator is going to be the medial side allow it to adduct tibial okay most of it's going to be on the posterior in the side for a little bit for bringing our toes up right extending our toes and then the dermatome a dermatome is an area of skin interated by anous branches of a single spinal ner so this is the skin this is the information they're sending to the skin and supplied by ner bra and the lower limb is going to be lumbar ner and so we have these things called this the these dermatomes and the skin is being interated by each of these spinal nerves okay so just all that this these things are is the skin being inated by these nerves at these different places are we okay that was a lot of information today but we're okay I hope you have a