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Sessions because of leave and um, the duration where we had notice period, we couldn't arrange them, but there's one session next week, which is on the first of May, it's a full day session, hands on. So, uh, I encourage you all to attend today. We have Mr Hud talking to us on spine biomechanics and Mr Lovell, uh who will be joining us and they, his um, will be talking to us on thoracolumbar fractures and if time permits, I will, um, uh talk about the painful condition in Children. Uh At least what I have come across so a whole bunch of cases to go through there. So anyway, let's uh, hand over to Mister H and um, get you started and make it entertaining. Ok. Um Hi. Uh both those live and those catching up. Um Hassan's gonna be taking chat and intervening at various points to, um, see if we can embed some knowledge. Please feel free to interrupt me. Um, if we're going along and I've put something in there that makes no sense whatsoever because as we all know, spines is a slightly different topic in the, um, realm of TN O and for some people. It takes a little bit of, um, you know, just, just getting it in, getting it in once it's in, it's fine, but sometimes it's just the getting in. So please feel free to interrupt. So my, oh, I've managed to go not to the beginning of the slide. That's never good. Is it? Here we go. Let's go back in my topic today is on spine biomechanics and stability concepts. Um I've aimed this at passing the viva. It is not high end. This is not gonna get you a seven or an eight in the exam. This is to try and embed some basic principles both for um exam and basic science knowledge that you are going to need. And the sooner you put it into your brains in training, the easier your training and your own calls will be um because obviously, um the spine trauma is the thing that tends to put the fear of doda into most trainees more than anything else generally. Um So let's crack on a little bit of basics about sagittal plane. Um Normal variation, cervical lordosis is between 2040 thoracic kyphosis between 2050 the lordosis 20 to 80. Um In terms of trying to remember that in your brain, you'll see that the first number is the same. So everything starts with a 20 as their normal variant and then just increases. And for those that don't know, 75% of that N normal lumbar lordosis occurs from the L4 to S one level in the lumbar spine. So a lot of lordosis is dialed in there. OK. Let's move on to some basic science concepts and the functional spinal units um which you need you have to know about and bears relation to the kind of column theories. I've put the more common one up first, which is Denny's three column theory. So we look at the left hand diagram first, you can see that the the the spinal column is split into three. You've got an anterior column which is the A ll anterior longitudinal ligament and the front two thirds of the vertebral body, uh the middle column, which is the posterior third of the virtual body and the PLL posterior longitudinal ligament, then you're into canal and then you've got ligamentous and bony structures. And it's important to remember the functional spinal unit when you are both working. So you know what you're doing day to day. But also for the exam, it's a combination of bony and ligamentous uh structures that form this functional spinal unit. Um The ligaments you've got there are the ligamentum flavum, the interspinous, the facet capsule which you need to know about and then the supraspinous liquid all numbered there. All of these ligaments are type one collagen other than the ligamentum flavum flavum, uh Latin for yellow and it's yellow because it's made of elastin. Er that is er a yellow color. That's your basic three column structure on the right. You've got a rotated 3d for those that struggle in two D which you know, the spine sometimes um does cause problems for those that, that have difficulty with spatial reasoning and, and twisting things in the spine. There's a kind of more oblique uh cut out of the same thing, essentially just showing you all the structures and how they interrelate. Um You won't get asked who Holdsworth is in the exam. But it's just to make you aware of the, another theory that, that preexisted the the knee uh column theory, Holdsworth was a er English er surgeon up in the er Yorkshire area. Um and essentially it splits it straight down the middle of the spinal canal and you've got an anterior column and a posterior column. And sometimes that's quite useful if you're running an ring about um potential stability. And the theory in that one was that if you only had one column, a affected, it's possibly stable still. But if you got both columns, then it's unstable again, capsular and disc er structures important um as we progress through this. So the function of each functional spinal unit, which when you multiply them across the whole length of the spine, uh gives you the, the a that ability of the total spine uh to function is to enable movement by allowing the, the appendages to come off them. And for us to ambulate and move to protect, protect the neural structures going through both the spinal cord and cord requiring running through the middle, but also the nerve roots as they exit via their respective neural foramina. You have to understand both for clinical practice and for the exam about white and Punjabi's stability theory. And essentially, we always have these big long definitions sometimes. And unfortunately, they are just a, a necessity of getting through exams and getting through training that Whiten Punjabi's theories is that the absence uh stability is the absence of abnormal strain or excessive movement or deformity under normal physiological load whilst protecting neural structures. And that's important that it's, it's, it's all of those because you will sometimes hear particularly any of those of you that have passed through Ipswich and those that haven't. You're now getting it from us, this concept of instability in a non injured spine, we will, it will be used and you'll hear it if you've been at Norfolk and Norwich and other uh some of the bigger units, the kind of degenerative instability, we will talk about where there is excessive strain or movement um and normal physiological load, which is causing root impingement or cord impingement. And so it's important that you're able to vocalize that concept across the viva table to the examiner. Um And also that you understand it for, for your day to day, you know, when you're, you're, you're seeing patients either in or, or or, or, or elsewhere. And that stability is a balance of the functional spinal unit itself at on those multiple levels. So that's why the muscular and central nervous system control of it, which has to be obviously, in order for it to work properly, you've got abdominal and thoracic pressures as well, which kind of counteract and, and, and help or, or go against it and then the rib cage, which you will hear us or other colleagues in other units use as the the fourth column. Sometimes when we're talking about thoracic injuries and the integrity of the rib cage and the sternum. Another concept that's important to grasp is the instantaneous axis of rotation. And essentially this is the point within and around each functional spinal unit around which the vertebra spins or the and which it can go in all six planes of freedom of, of movement. It moves in each unit. As you see, there's a cervical spine here and these diagrams are just showing that it changes slightly, but you'll see that it generally sits around the border of the anterior two thirds to the posterior two thirds of the per posterior vertical body wall. So that allows the axial rotation, that twisting. You've got the flexion and extension and then you've got lateral flexion as well if that doesn't make sense to anyone. Shout now good. We shall move on. So now we're getting towards free body diagrams, the dreaded exam question. So this is the start of it. So having talked about the joint center or the instantaneous axis of rotation, we've got a compression reaction force coming up here that's acting through that pivot. We're just, we're gonna go into this. And I do want you to stop me when the whole concept of free body diagrams makes your brain go fuzzy. Um As it did mine when I was trying to learn them back at back at your stages. So please feel free. We know it's a difficult concept to get your head round. Sometimes this is the pivot at the joint center, the instantaneous axis of rotation.