all right everybody welcome to a talk on functional anatomy of the lumbar and thoracic spine and let me get my camera going so you can see me and a little bit wider and larger because i'm gonna need this for our anatomy and functional anatomy piece and so before we get started about anything related to the lumbar spine or the thoracic spine or the sacral spine for that matter i need you to understand so this is going to integrate lower extremity with upper extremity right those two classes the hip pelvis and lumbar spine are an integrated functional unit one affects the other so the pelvis whatever's going on with the pelvis pelvis and the hips is going to influence the lumbar spine typically we don't have enough mobility in the hips and pelvis so that unfortunately we're going to talk about this a couple times uh kind of increases the needs of mobility from the lumbar spine and the lumbar spine is supposed to stabilize so integrated functional unit and so we've got the pelvis here right we've got five lumbar spine natural lordotic curve and so we've got forces as you can see in the slide transmitted from the bottom up ground reaction forces through the kinetic chain and body weight forces from the top down all converging where they all converge at one point lower and upper extremity forces right here at the si joint hopefully this is review for you so the pelvis is the fulcrum okay if you think about a teeter-totter the fulcrum is the center and then the two levers which two people sit on are you know in this case the arms and the legs and the pelvis is in the middle of the tug of war if you will also you see there it's the relay station you think about a relay station whether it's phone calls etc it relays forces right it stabilizes and then relays forces up and down so those of you who train athletes probably already knew if you want to throw the ball faster or kick the ball harder or further you've got to start with stabilizing the pelvis and strengthening that finally some people call it the traffic circle think about those roundabouts in traffic right you get in there and then it spins and shoots you off in a different direction right think about the pelvis as that so therefore this is a key region i and i gotta start here before we talk about anatomy this is a key region a key to the kinetic chain that you should assess always not only if you think somebody has a lumbar spine pathology but up and down the kinetic chain if they have pathologies look here first to see how this is stabilizing itself and moving okay this is bonus material for you some of you probably um either have taken a movement interventions class or you want to take a movement interventions class this is a slide from another class i teach and so gray cook if you want to look it up gray cook invented the fms functional movement screen and i'm stealing this idea from him because i love it the body is a kinetic chain each joint is a link in that chain and as you see here from the foot and ankle to the head each of the links has um various needs it's either that joint needs more mobility and that's what you give it as a clinician in therapy or it needs more stability and it's a really nice pattern if you can just memorize it at the ankle the ankle is a pretty stable joint it tends to need more mobility okay the knee the knee um is a pretty mobile joint right it moves in three planes of motion it needs stability from you okay moving on now we get to the why am i doing this because we get to the pelvis and the lumbar spine here and you see here the pelvis and the hips are very stable joints that doesn't surprise any of us they need to be ink have their mobility increased so that's the need of the hip and pelvis you know where i'm going so the lumbar spine is highly mobile it moves a lot particularly in the sagittal plane flexion and extension but also rotation it moves a lot it needs stability okay why am i spending time here if you understand this about the lumbar spine and the pelvis then you can start to implement treatments and also you can start to see how it becomes dysfunctional the hips and pelvis usually are dysfunctional because they don't have enough mobility the lumbar spine is usually dysfunctional when it it has too much mobility and you need to give it dynamic stability core strengthening right okay uh so the core i've been talking about the core a lot right just really quickly that means the lumbo pelvic hip complex it's the location of the center of gravity i don't know if you knew this but 29 muscles attach onto the pelvis 29 that then lever on the pelvis to go up or go down right and then you've got the deep stabilizers in the pelvis that rotate the hips okay so it needs stability so that you can effectively accelerate and decelerate motion but a weak core can lead to as you see on the bottom right uh all kinds of pelvic dysfunctions and pelvic pelvic what i mean is postural dysfunctions including pelvic dysfunctions those can produce pain all right so let's get into the lumbar spine now that we have that uh functional anatomy okay so let's talk about a little bit of background and significance of low back pain you first need to know that most adults in the u.s will experience low back pain 80 8 out of 10 so you're going to be seeing this a lot in your clinical practice okay an acute injury to the spine during athletic competition accounts for about 15 10 to 15 of all spine injuries which uh kind of indicates also that there's a high percentage of chronic spine injuries right at least in an orthopedic setting um probably different from other joints that we'll cover there's a significant association between chronic pain in the back and the back and spine and mental health issues like depression okay as you can imagine people with a lot of pain over a long period of time can start to get depressed or anxious okay so it's we'll talk about this when we get into uh physical exam and lab but it's important that we assess our patients mental health status is there an emotional distress that's going on with this back pain do they have a negative expectation of recovery i've worked with uh motor vehicle accidents uh patients that haven't been well for a couple years and so that's going to indicate um or affect how they how they improve okay and so quick check on their mental health status would help to inform uh maybe their probability for being successful in your treatment let's talk about some clinical anatomy uh of the spine so here we see the clinical anatomy of the entire spine right starting with the brain into c1 just below the brain into a brain stem and the cranial vault into cervical spine which is a normal lordonic curve it curves in an anterior direction thoracic spine of course is a kyphotic curve meaning curves towards the posterior direction and then it alternates lumbar spine right here as we look at the lumbar spine it's a lordotic curve but can't you see already that l1 and 2 are pretty straight and rigid and have very little mobility and as we get into l4 l5 and s1 here you see a big curvature l4 l5 and s1 ladies and gentlemen is where a lot of mobility happens it's also where the vast majority of pathology happens so right away we're narrowing down our differential diagnosis process to a few segments where uh pathology is more likely to happen again lordotic curve kyphotic curve lower dotted curve kyphotic curve with the sacral spine five vertebrae there so uh you all know this uh but just for review the c-spine has how many vertebrae seven but it has eight nerve roots right because uh the eighth nerve root exits below c7 and in between t1 so right off the bat actually let's just uh go there the nerve roots are named so the c2 nerve root actually exits between c1 and c2 it's above c2 okay that's true all the way down to c7 but then you've got a c8 nerve root but not a c8 vertebrae which means that that c8 nerve root exits below c7 so from c7 down the roots exit below the vertebrae for which they're named so the l5 nerve root exits below l5 all right seven certain cervical vertebrae 12 thoracic how many lumbar spine vertebrae five and sacral spine another five okay and uh obviously as we said we'll get into these but you'll really get into these with a therapeutic exercise class a lot of dysfunctions can happen of the lumbar spine you can have kind of more kyphosis here that you see in number two or b you can have hyper lower doses that you see in a you can have a very flat rigid spinal column these folks are prone to disc herniations whereas hyperlordotic these people are prone to extension-based injuries like facet joint syndrome and spondylopathy you've got pelvic dysfunctions this is a pelvis that's rotated backward or counter mutation and then you've got scoliosis all right let's talk about some comparative anatomy of the cervical thoracic and lumbar spine i think you know this but let's just review the cervical vertebrae is not unlike the thoracic and lumbar vertebrae from a bird's eye view in terms of they each have a foraminal uh opening right foramen for the neural tube the spinal cord to exit however and they all have spinous processes and facet joints and or transverse processes but the spinous process in the cervical spine is is much less is much smaller i was going to say much less robust but much smaller than the thoracic spine and the lumbar spine you see how as we go down the spinal column they get larger why do you think they get larger from the cervical to the thoracic to the lumbar spine the the bodies here on the right side because they're weight bearing right there they're more load-bearing so the the vertebrae naturally has to be larger okay um these serve as muscle attachments the spinous and the transverse processes from a lateral view you see that at the t-spine the thoracic vertebrae the spinous process is longer and more angulated down you guys this is one reason why in the thoracic spine you have so little mobility because these uh spinous processes prevent full extension in the t-spine one you know let's say this is t2 that would bang up against t3 down here right if you go into hyperextension they have much more flexion than hyperextension okay moving on and then the lumbar spine large vertebral body a disc comes in between one lumbar vertebrae and the other um let's see what else do we want to know oh these transverse foramen or foramina right here what do you think goes through there blood supply yeah in the cervical spine this is the vertebral artery that provides blood flow up and down uh the lumbar spine okay let's go into some more anatomy these three pictures on the right are really going to help us with the bony anatomy here transverse process okay so one vertebrae sits on top of another vertebrae in three particular areas the first is the vertebral body and the second and third are both facet joints and so one vertebrae sits on top of another at three points the body and then the right and left facet joints okay the facet joints are formed by transverse processes an inferior and a superior that meet together and then we've got ligaments here where my cursor is and that ligament makes up a synovial joint and that synovial joint is like any other synovial or diarthrodial joint in the body it can refer pain it can get swollen all of that okay spinous processes you know facet joints we just covered pars inter articularis that's a a really important um structure especially when we get into the lumbar spine if i were to kind of remove these little um i don't know you see facets there what this bony arch right here see this bony arch kind of like a bridge those are called pars inter articularis between articulating surface surfaces that the reason we're spending time here is because that is prone to degenerative fractures in people with stress injuries in their lumbar spine and elsewhere okay that's the pars inter articularis or we just say parse intervertebral foramen you've got a huge foramen here that houses the cord itself but then you've got foramina see this one the foramina is formed by one vertebrae sitting on top of the other that foramina is where nerve roots exit out of okay so the nerve root that then supplies the left side of the body or the right side of the body cost of vertebral joints we we said this in the thoracic spine that's where a see here it's a really nice picture where a rib meets the vertebral body so that is a very stable rigid joint and like we said it also helps to prevent motion and add stability to the t-spine superior inferior costal facets we already talked about and of course we've got to remember the this is a functional unit with a lumbar spine in the pelvis so s i joints and then the sacrum that that terminates with the coccyx are also very important to the anatomy of this region all right as we're getting deeper into now not just the whole column but the lumbar and sacral spine in particular there's an interesting um we'll say we'll say pathology but really it's a um an and an anatomical anomaly how's that for a tongue twister an anatomical anatomy anomaly and that is we all know that uh most of us have five lumbar spine vertebrae by the way if you use the pelvis and you go across we'll learn this in lab you go exactly across you're on l4 that's the fourth lumbar vertebrae so this must be l3 l2 l1 t12 right one two three four five s1 so some of us have an extra lumbar vertebrae we're just born with it that's called lumbarization so we have a sixth lumbar vertebrae those of us who have that we've got more mobility in the lumbar spine than others okay and so you may see this in a patient it's not common but you may that's called lumbarization the reverse is true some of us lose l5 and it's fused to the sacrum so we've got an extra sacral vertebrae and those people have less mobility okay so that occurs when the fifth lumbar vertebrae fuses to the sacrum and so keep this in mind if you have somebody with low back pain and and you feel like they might have hypermobility or hypomobility and they're tender to palpation right in here l5 and s1 send them for an x-ray as you see there you may find that they have lumbarization or sacralization it's not a huge deal uh the surgeon or the you know x-ray tech will usually send them right back to you and we'll rehab them it's just something that you should know about let's get into the disc itself this is a wonderfully complex uh uh anatomic structure discs let's talk about the components of discs so you've got dense fibrous ligamentous tissue out on the periphery of the disc kind of the teal structure here it's not teal in real life that's the annulus fibrosis this is very dense fibrous um and then the nucleus pulposus is a spongier uh more water filled component of a disk okay this is a wonderful shock absorber what happens in a disc herniation excuse me is that the nucleus pulposus becomes loaded usually from an anterior direction posteriorly pushing posterior and it starts to push out posteriorly and it encroaches on a nerve okay it's not the annulus fibrosis per se that bulges it's the nucleus that pushes through the annulus and the nucleus as we said has a high water content 60 to 75 60 to 70 percent water uh particularly in folks your age in their 20s and 30s as we age we lose water content this explains why people in their 50s and 60s are much more prone to herniating a disc and how you almost never will see a 15 year old with a disc herniation okay um we call it hydrophilic and hydrophobic hydrophilic discs uh have more water content and hydrophobic it's like they're scared of water right uh have less okay so our just become more hydrophobic as we age key uh key anatomic uh process there they're highly elastic the nucleus pulposus semi gelatinous substance you know when i was going through school um doc's used to say it's like a jellyfield donut like a raspberry jelly filled donut i've heard since then i've heard spinal surgeons say this is more like it's it's it's tougher substance almost like crab meat is what i've heard it described as sure it's spongy but it's not it's not jelly like okay all right moving on so there's 23 intervertebral discs there's no disc between c 0 and 1 they start at 1 and two and go down all the way into the lumbar spine so here's our crab meat here instead of a jelly donut what i want you to know biomechanically about the discs is that they're very resistant resistant to compression that's a good thing as your body loads through the lumbar spine they resist compression what they don't like is torsion or shear force so anterior posterior direction in that sagittal plane or um torsion in the transverse plane they don't like that so much i'll just say to you this way if you want a herniated disc in the lumbar spine do a lot of flexion loading and rotation like bending over to pick something up and rotating to your right or to your left that's how you herniate a disc okay and so you see here you've got discs you've got vertebral bodies you've got the spinal cord and then this of course would be cerebral spinal fluid and space here's back here is the vertebrae the spinous processes this is fun i just added this to your powerpoint slides go ahead and click on this to watch a nice simulation of how a disk functions i really like this and enjoy this if you want to really see how the disks are meant to function and how they can become herniated of course i can't talk about discs without talking about ultimately if they protrude they're going to encroach either on the cord itself if they go directly posteriorly or on a nerve root if they go posterolateral okay and then every nerve root at every level of course synapses and you've got afferent and efferent supply so any damage to a nerve root can disrupt sensation to the skin or muscles etc and that are supplied by that nerve root or it can disrupt efferent action or muscle contraction let's talk about ligaments of course you know that ligaments are responsible for the the static stability of structures and the spine is no different you've got wonderful ligaments on the anterior and posterior side and then interspinous ligaments between each spinous process the spine does not lack for stability from a ligamentous perspective okay you've got anterior and posterior longitudinal ligaments anterior this thin film around the anterior body this is the anterior side posterior of course is where the spinous processes are this anterior longitudinal ligament primarily resists extension whereas the posterior longitudinal ligament primarily resists flexion and then you've got a really fun um unique ligament the ligamentum flavum which is 80 elastin why does that matter so the ligamentum flavum right here you see it it runs on the posterior side of the canal and it can lengthen almost like a muscle okay and we need it to do that so that we can accomplish full flexion bending over touching our toes or delivering a pitch etc this ligamentum flavum travels c2 to s1 in in essence the entire spinal column um and then of course like i said we've got inner spinous ligaments responsible for the stability of the inner segmental vertebrae that's fancy well let's get down to business how do you sprain one of those hyperflexion or hyperextension in some cases rotation can sprain those and then all of these are locked into a facet joint that has facet joint ligaments a ligamentous capsule that's three-dimensional wrapping around the facet joint and again that can refer pain just like any other synovial joint i really loved this picture because it gets us really deep into these inner spinous ligaments uh here you see the posterior longitudinal ligament running the length of the spine here you see the broad anterior longitudinal ligaments we've got discs here with the annulus fibrosus and then our friend the ligamentum flavum running all the way down and then you've got i didn't even name these the inter-transverse ligaments stabilizing one transverse vertebrae one facet to the other okay let's talk muscles so in general muscular anatomy you've got muscles the extrinsic large powerful muscles that provide movements associated with the upper extremity the scapula attach onto the pelvis and then you've got intrinsic muscles that are more slow twitch even richly supplied with proprioceptors that that influence stability and small movements okay so let's talk about those big powerful movers of course we've got the lats and erector spinae yeah you all know about the erector spinae and the lats that then attach onto the lats go on to this thoracolumbar fascia dense rigid connective tissue that that connects these muscles onto the pelvis into the sacrum this is the top layer if we go down a layer now we've got erector spinae which is the longissimus spinalis and semi spineless right remember your anatomy and then we've got the deepest layer down here we see rotatories right which do what their name says they rotate but really what they do ladies and gentlemen is stabilize one segment on another okay and the multifidei right here the rotatorys will move they'll rotate but the multifidei are those deep stabilizers okay then of course we've got the 29 pelvic muscles so let's go into those that deep layer so these three layers we said of the erector spinae and then the rotators right here love this picture these inner transverse cereal eye can't even say it um what do you think these muscles do obviously they're not large movers right let me go down here obviously they're not large movers those are stabilizers okay so when we're doing plank exercises and we're doing hand or knee drivers or like fire hydrant planks where we're bringing our knee in the transverse plane we're really using these muscles to stabilize the spine and that's what they need to do so the multifidus this is not a therax class but i want to geek out for a minute so the multifidus and the transversus abdominus and the rectus abdominis enter into forced couples that means two joint two muscles acting on either side of the joint working in synergy to stabilize the joint they do all of that to stabilize the pelvis so if you're patient let's anyway i'm not going to pick a patient but if your patient is having a stability issue chances are that you need to get in and really strengthen these deep rotators but but since this is a pathology class if if a patient doesn't stabilize their pelvis with these deep muscles and transversus abdominis is huge you can read the literature if they don't do that they're going to start having back and pelvis pain all right just for fun you guys i want us to think a little bigger now again i'm off topic a little bit what i just want to show you is that the human body is complex and the human body um there's a axiom called beavers axiom and it says that the brain knows not of muscles the brain only knows movement uh what does that mean i think when we memorize anatomy we tend to think well one muscle does this and that's true like in normal simple function when we're not bearing weight really the brain doesn't tell the iliopsoas i need you to contract now what the brain says is uh where's the iliopsoas iliopsoas i need you to move in a multiple plane function with multiple muscles to stabilize this whole front part of the body when this person wants to run okay so i you don't have to memorize all this this is just off topic but it's super fun these muscles in the lumbar spine what i'm saying to you is they interact in complex ways with other muscles that i'll call their friends throughout the body to stabilize and to move the body uh i hope you really geek out on this in your therapeutic exercise class um i i'm happy to share more information with you if you'd like but i just wanted you to see this some of you are familiar with what are called anatomy trains that's what you're looking at here here's some of them here's a better picture right the hip flexors are now in sync with the deep abdominal muscles and the adductors to stabilize the entire anterior kinetic chain to prevent pain and instability right now can you see the interconnectedness of the lumbar spine to the pelvis and the hips that's your rhetorical question of the day of course you can and here's the back spiral line some people call this the posterior chain okay quickly on neurology and i'll let you go so we're beginning to understand right c2 all the way to s1 and 2. uh the the column uh the spinal cord is happening i misspoke there a minute i'll i'll i'll uh get make it all clear to you in a second where's the uh key things we should know well i already told you one of them c8 nerve roots exits just below c7 right and then after that we've got t1 vertebrae here and the t1 nerve root exits um right above it for which it's named all the way down to l2 the spinal cord ends at l2 that's the part i misspoke i didn't mean to say that the chord goes all the way down to s2 because at l2 the chord ends and it becomes what anybody i had an anatomy professor back in the day david ortecho and that man did not say kata equina he said kara akina that's the way i pronounce it kata akina is the horse's tail right see this horse's tail what am i saying you don't have a spinal cord below l2 you've got nerve roots like a horse's tail okay more on that to come and so what are the major players we need to know well in the c-spine we'll get to brachial plexus but we're not there in the lumbar spine you've got a lumbar plexus l1 to l4 and then you've got a sacral plexus you can barely see it down here okay which is the sacral nerve roots but but together we just call it the lumbosacral plexus and the major player you're going to need to know is out of the lumbosacral plexus emanates the sciatic nerve from l4 to s2 ish okay the femoral nerve is above that that exits out right here you can barely see it l2 l3 and l4 the femoral nerve supplies the front of the thigh we'll talk about this more the quad area the sciatic nerve supplies the posterior thigh hamstrings etc okay so study this out i've got plenty more slides to come we break apart the lumbo uh sacral plexus into a lumbar plexus l1 to l5 l2 to l4 and then the sacral plexus primarily l5 to s2 l1 to l5 innervates that anterior medial muscles of the thigh that's what we said right l123 etc become that femoral nerve two through four posterior branches form the femoral nerve anterior branches form an obturator nerve okay this is what we're talking about right here right there and then the sacral plexus is below that primarily l5 to s2 it innervates the butt the posterior femur in the entire lower leg but here for our purposes we're going to geek out a little bit on the sciatic nerve so l4 to s3 let's talk about that so the sciatic nerve exits out of this greater sciatic foramen inferior to the pelvis and then immediately we've got a piriformis muscle and i know you know that that comes over the top of it and sometimes the sciatic nerve bifurcates the piriformis muscle and most people are more prone to piriformis syndrome that piriform um that sciatic nerve becomes this ladies and gentlemen is wrong this needs to be down here i'll get to that in a minute anatomists or artists sometimes wrong the sciatic nerve becomes the tibial nerve right above the popliteal fossa all this text is right here you guys right above the popliteal faucet goes deep and supplies that deep posterior compartment of the leg and then it sends off another branch that becomes the common peroneal nerve now we're going to talk in a later on about how the common peroneal nerve um bifurcates further into a deep and a superficial nerve okay very important that you understand neurology and i'm just going to say it would be hugely important that you memorize this for all of us we need to know for instance if somebody's foot goes numb or their big toe goes numb which nerve root could possibly be implicated so to answer questions like that you simply have to memorize this peripheral nerve distribution of the lumbosacral plexus others of you who go to pt and pa school i know this from experience if you memorize this you will not need to memorize it in pt or pa school and you'll teach all your colleagues and your professors will say where'd you go to school and you'll say i had dr sullivan at point loma no please don't say that i don't need that um but what i the reason i gave this to you is because it's hard to find first of all the entire nerve um distribution with exactly what we just said tibial nerve becomes the common peroneal nerve which then becomes the deep and the superficial peroneal nerve you see here the superficial peroneal nerve supplies the lateral compartments of the peroneal or perineal muscles whereas the deep peroneal nerve goes lateral and now see this is posterior now it goes anterior and supplies the anterior compartment so tibialis anterior peroneus tertius uh extensor hallucis longus extensor hallucis brevis okay all of those foot extensors are the deep peroneal nerve whereas the peroneal muscles longest and brevis are the superficial peroneal nerve now what is the tibial nerve supply again i know i just said it so i don't expect you to have memorized it it's the deep posterior compartment so that's soleus flexor hallucis longus flexor digitorum longus tibialis posterior all right now we're rocking another picture of all of those the plexus becoming the peripheral nerves and now here we're adding cutaneous cutaneous supply okay that's anatomy that's neuroanatomy in like 30 minutes when we get to lab we'll go over how to assess myotones dermatomes deep tendon reflexes using our textbook you know and love this already you've studied it for the lower extremity so it should be pretty um plug and play for us when we get to lab okay that's it thanks for listening the next video i'll do a clinical exam of pathologies to the lumbar spine