The Worst Kind of Back Pain | Herniated Discs & Sciatica

back pain is no joke especially when it involves bulging and herniated discs as well as that associated nerve pain that people often refer to as sciatica so in today's video we're going to take a look at actual discs on the cadavers in the lab discuss what's actually going on with bulging and herniated discs and again talk about that collateral damage and symptoms when those nerves get involved so let's do this [Music] so first let's talk about what a disc actually is discs are technically called intervertebral discs and that's because they're found in between the bones that make up the spine or the vertebral column and we refer to these bones as vertebrae or vertebra for singular now the majority of the vertebrae have what's called a vertebral body and this is the largest component of each vertebra and it's kind of this block-like mass of bone and it's where the weight or the forces are distributed throughout the spine and so we plot those discs in between the vertebral bodies of the vertebrae now these start at c2 or the second cervical vertebra and the discs will continue down the spine and end at the sacrum specifically between l5 and s1 now the discs will actually make up about 25 percent of the overall height of the spine and it is true that you technically are a little bit taller when you first wake up in the morning because as you stand throughout the day and the discs still with the compression some of the watery component of the disc will kind of ooze out and the disc will get a little bit thinner and lose a little bit of height but then when you go back to sleep at night the spine gets decompressed and the central portion of the disc will get rehydrated now i mentioned the central portion of the disk so let's actually talk about some of the specific components of the disk because that'll help us understand how they function as well as what happens when they get injured the outer portion of the disc is called the annulus fibrosus and this is a tough ring of tissue made of fibrocartilage the central portion of the disc is called the nucleus pulpulsis and that's a pretty good name because we often think of things in the center or in the middle when we use the word nucleus and pypulsis because the nucleus pulses is made of this pulpy gelatinous substance even has a watery component to it which we hinted to earlier when we talked about water oozing out of the disc and the disc losing some of their height and now we know it's coming from the nucleus of pulses but the nucleus pulses as i say it so many times is a nice little shock absorber for our spine and you can think of the annulus fibrosis as this tough connective tissue ring that contains the nucleus or keeps it in the middle now my students will often compare the anatomy of disc to the anatomy of a jelly donut and that's an okay comparison i guess the problem is with the jelly donut is when you compress it it kind of just stays smooshed but our discs are just so much cooler than that our discs when they deal with that compression or that smooshing force they have that ability to bounce back or recoil so now that we understand the specific components of the disc this is going to help us more clearly understand the specific disc injuries but before we get to those disc injuries i do want to mention one other important thing when it comes to discs and that is discs are avascular meaning they do not have a direct blood supply so you might be thinking well how do these tissues or these discs stay alive if they don't have a direct blood supply how do they exchange nutrients and waste products well discs will get their nutrients through diffusion from blood vessels that are close by or in other words from blood vessels that are supplying structures that are near the disk for example like the vertebrae or those vertebral bones we talked about earlier and this is enough to help maintain the disc but we're gonna see that this is a limiting factor when it comes to disc injuries and even healing from those injuries and so you might also think is there anything i can do to increase the blood flow or the blood supply to the discs and you're not going to grow tiny little new blood vessels that are going to penetrate into the discs that's not going to happen but through certain stretches and mobility exercises that can occur through things like yoga we can see that the spine or the disc can get decompressed and that we can increase the general and overall blood supply to those blood vessels that are close by and this could potentially help speed up the exchange of nutrients and waste products with the discs but did i mention yoga yes i think i did which allows for one of my classic shameless segues to say thank you to the sponsor of today's video yoga body teachers college they specialize in science-based online certification programs for yoga teachers yoga breathing coaches yoga trapeze teachers and stretching coaches if you're interested in starting a new career or a side job helping people improve their health overcome injuries manage stress and live their best lives longer yoga bodies courses might be right for you yoga body takes a science-based business positive approach to yoga they turn passionate students into successful teaching professionals since 2007 yoga body has certified over 23 000 teachers in 41 countries they are backed by yoga alliance american council on exercise and even american council on education making them one of the only schools in the world eligible for college credits yoga body has put together a free report for you called how to choose a yoga teacher training program you can access it immediately at yogabody.com forward slash iha so let's talk about some of these disc injuries as well as some of the terms that are used to describe the injuring of a disc because you've probably heard of all sorts of terms things like herniated bulging ruptured slipped discs but do these all mean the same thing no there are some distinctions here and the two most commonly used terms to describe an injured disc in medicine are bulging and herniated discs a bulging disc is when the outer portion of the disc that annulus fibrosis is bulging outward yes i understand it is earth shattering to say a bulging disc is bulging outward but there is an important distinction here with a bulging disc the annulus fibrosis remains intact just think of it as kind of getting smashed and stretching outward but one of the best analogies that i heard to describe a bulging disc think of a hamburger where the meat patty is too big for the bun and the bun the top of the bun on the bottom of the bun would be the bones in this analogy and the meat patty extending beyond the margins of the bun would be the disc and it doesn't have to involve the whole circumference of the disc it can but many bulging discs just include anywhere from 25 to 50 of the outer circumference of the disc so you could maybe think of it as 25 to 50 percent of the meat is only extending beyond certain margins of the bun with our wonderful food analogy now bulging discs tend to occur with age as that cartilage becomes more dehydrated with age and those tissues lose some of their strength in integrity a herniated disc on the other hand is when that annulus fibrosus actually gets cracks and tears in it which will then allow the nucleus pulses to protrude outward now a herniated disc is synonymous with some of those other terms like a ruptured or a slipped disc now this often occurs with certain acute injuries say somebody lifts improperly and they rupture or they herniate the disc but keep in mind an aged bulging disc is also going to be more at risk for herniation now a herniated or bulging disc has got to cause a lot of pain right well yes and no for example there are situations where say someone went in for imaging for like an mri that had nothing to do with back pain or a disc issue and they just incidentally find through that imaging that the person had a couple of bulging discs that they weren't experiencing pain from compare that to something that happens more suddenly say someone is lifting something improperly and they herniate the disc right then and there and feel that immediate pain now there's some reasons for these distinctions here one is that the discs actually don't have a ton of pain receptors and because there's not a lot of pain receptors it typically is going to take something a little bit more severe and more sudden to really get those pain receptors fired off so that gradual bulging of the disc that can happen over time as long as that bulging disc doesn't irritate surrounding structures it could potentially go unnoticed as compared to that other situation where somebody's lifting and they tear that annulus right then and there rupture the disc that's going to cause that immediate pain but even still a lot of the pain that's associated with it and sometimes it's the majority of the pain that's associated with disc issues is when that bulging or ruptured disc irritates or compresses surrounding structures those surrounding structures could be blood vessels ligaments and of course the nerves the inner vertebral discs are in close proximity to spinal nerves which originate off the spinal cord and the spinal cord is located within the vertebral canal sometimes referred to as the spinal canal these nerves will exit the canal through a hole called the intervertebral foramen and again this is in close proximity to the discs now disc bulging or herniations and the potential collateral damage that they can impose on the spinal nerves could happen at any spinal level that you would find a disc and remember we said that was from c2 down to the sacrum now these principles of nerve irritation and nerve impingement can generally be applied to again any level where you'd find a disc but we're going to focus in on the most common areas where you find disc bulging and disc herniations and that's in the lower lumbar region specifically l4 and l5 so here we are zoomed in to the lumbar spine of cornelius skeleton you can see the l4 vertebra the l5 vertebra and the sacrum down below you can also see the disc between l4 and l5 and the disc between l5 and the sacrum and of course the l4 spinal nerve the l5 spinal nerve the s1 spinal nerve and even those s2 3 and 4 spinal nerves down below so let's say you have a bulging or a herniated disc that's compressing or irritating that l5 spinal nerve or maybe even the s1 spinal nerve what would some of the symptoms be and how could you figure out what specific spinal level or spinal nerve is being irritated or compressed well you could go straight to an mri but i feel like that's a little bit of cheating at least to do initially because a skilled clinician can actually get a pretty good idea of what specific spinal nerve is being compressed by doing some testing just in the office or in the clinic there are these things called dermatomes and myotomes a dermatome is an area of the skin that's innervated or served by a specific spinal level or spinal nerve so there's l5 that controls a specific area of skin s1 goes to a specific area of the skin so the clinician would test those specific dermatomes associated with that spinal level for things like numbness or tingling or other abnormal sensations often the pain can radiate to those areas as well there's also the myotomes i mentioned a myotome is a group of muscles that are innervated by a specific spinal level so you could test those muscles that are innervated by say l5 for maybe some weakness the challenge of that muscle testing is the majority of muscles in the human body are innervated by more than one spinal level for example the hamstrings are innervated by l5 s1 and s2 so if the l5 spinal nerve is being compressed the hamstrings would still be getting signals from s1 and s2 so that might be harder to tease out if there's any weakness in that muscle when you're comparing like the good side to the bad side but whenever we talk about rupturing herniated or having a bulge disc in these lower lumbar areas and compressing nerves like l4 l5 and some of the sacral nerves we have to have a discussion about sciatica the term sciatica is used to describe pain that's radiating along the pathway of the sciatic nerve and this can be caused by compressing a nerve root at l4 l5 s1 s2 and or s3 and the most common cause of this is having a bulging or herniated disc below l4 or below l5 compressing one or more of those five spinal levels that i just mentioned now what's interesting is that many clinicians actually prefer not to use the term sciatica when discussing these issues and prefer to use a term that's a little bit more accurate called lumbar radiculopathy radiculo just means nerve root pathy just means disease state or an abnormal condition and sometimes they'll use the phrase lumbosacral radiculopathy if a lumbar and a sacral nerve root is being compressed or affected and so the reason for these distinctions is that when you compress one of these spinal nerves through a herniated or bulging disc up at this region the sciatic nerve hasn't even been formed yet the sciatic nerve forms lower down in the pelvis and it gets contributions from these five spinal levels l4 l5 s1 s2 and s3 all send branches or contributions to form the sciatic nerve lower and that sciatic nerve will emerge in the gluteal region underneath a muscle called the piriformis and then we'll continue down the back of the leg so you can see why if we're just affecting say the l5 spinal nerve that's not technically compressing the sciatic nerve yet and so that's why some prefer that distinction over just calling it sciatica even though the pain can run down through that sciatic nerve now there's two other things we have to cover here one is you might think that if we had a herniated or bulging disc below l4 that it would actually affect the l4 spinal nerve but typically it doesn't it actually compresses and affects the l5 spinal nerve why in the world does that occur the other thing that you might have been wondering or thinking we've talked about compressing sacral spinal nerves if you look down on the sacrum there's no discs there so it obviously has to occur from here or here but how is that happening well to help us understand those questions that is a story of development while you're developing inside the cocoon of love that we call the uterus inside of mom so this developmental story is specifically about the spinal cord and this picture is going to help us with that story as well as help to answer the questions that we just posed so let's orient ourselves to this picture this is a posterior view of the lower spine you can see the l4 vertebra the l5 vertebra and the sacrum and then we've got these nerve roots coming down the blue are the lumbar nerve roots and the red is just representing the sacral nerve roots i did mention this is a posterior view so in order for us to see these nerve roots you'd have to do some cutting so we have a l5 vertebra to show you here and so in order to see those nerve roots we would have to cut here as well as here and pull that segment of the bone off so you can see those nerve roots running through that vertebral or that spinal canal we've even got a little makeshift cardboard disc where we've got a poor little nucleus but pulses herniating out and we'll talk about that in just a minute but you might be thinking well we're looking in the spinal or vertebral canal here shouldn't we see the spinal cord and the answer is no the spinal cord in an adult actually ends at l1 l2 right at the superior border typically of l2 in an infant or a newborn it goes down as far as l3 and l4 but what you're seeing is that the actual spinal cord segments say like the l5 spinal cord segment isn't lining up with the l5 vertebra or bony segment there now that wasn't always the case when you were developing inside mom there was a time where the l5 spinal cord segment did line up with the l5 vertebral or the bony segment there but something occurs called differential growth and what that means is that the vertebral column or the spine grew faster than the actual spinal cord and so to accommodate that differential growth these nerve roots had to grow out longer and to again accommodate that differential growth between the spinal cord and the actual spine itself and so this group of nerve roots actually got a name called the kata equina as it resembled what they thought of horse's tail but this anatomy in these relationships will help us answer those questions that we posed remember we said a herniation of the l4 disc that's associated with the l4 vertebra you'd think that it would compress the l4 nerve but i said typically that l4 nerve gets spared and you can see from this relationship how that herniation i've drawn here would actually affect the l5 nerve and if i come back to this little makeshift drawing that i have here typically the herniations are posterior lateral so posterior and just slightly to the side and that's how we've drawn it here as well as down here the disc that's associated with the l5 vertebra or below it you can see how it would spare the l5 nerve but compress the sacral nerve and that answers our second question how can you have sacral nerve issues when there's no discs to herniate in the actual sacrum now some of you might be taking this even further thinking well what if that herniation was even greater or larger or just even more central and you could see if we just moved it slightly more medial or had more of a central herniation you could affect even more of those sacral nerves so hopefully this picture can kind of give you that idea is at least give you that visual how you can affect certain nerves spare other nerves and even affect more sacral nerves than you might actually anticipate with no discs actually being in the sacrum thanks for watching everyone if you're interested in potential treatment options for back pain including sciatica and disc injury we covered some of that in our previous back pain video so we'll link that to this video also if you're interested in pursuing anything with yoga check out the link in the description below with yoga body the sponsor of today's video and as always like subscribe if you feel the need leave some comments below and we'll see in the next video [Music] [Music] you

Channel: Institute of Human Anatomy

Views: 2,303,232

Keywords: anatomy, anatomy and physiology, back pain, back pain relief yoga, sciatica pain relief, sciatica, what causes sciatic nerve pain, what causes sciatica pain, what causes sciatica, nerve pain in leg, nerve pain in foot, herniated disc, herniated disc symptoms, herniated disc exercises, bulging disc, worst back pain, back pain treatment, human body, sciatic nerve, nerve compression in lower back, nerve compression in leg

Id: YPlLK6y--8g

Length: 17min 46sec (1066 seconds)

Published: Tue Aug 23 2022