Core Uncovered

[00:00:00] Speaker A: Have you ever really stopped to think about, you know, the core of your body? I mean, really think beyond just, like, abs? [00:00:07] Speaker B: It's such an intricate system, isn't it? So much going on under the surface that we just take for granted. [00:00:12] Speaker A: Totally. And that's exactly what we're diving into today. We're tackling the musculoskeletal system. Bones and muscles, part one, the torso and spine. We've gone through this really comprehensive manual aimed at movement pros, and our mission is basically to pull out the absolute essentials for you. [00:00:31] Speaker B: Exactly. The goal here is to give you that solid understanding, sort of a shortcut, without making your head spin with, you know, overwhelming detail. Think of it like we're peeling back the layers. How does your torso actually move? How does it stay stable? It's all connected. [00:00:45] Speaker A: Yeah, Precisely. And look, this isn't just for anatomy nerds. Getting these basics can honestly change how you think about your own movement, posture, even just how comfortable you feel day to day. It's really about giving you practical insights. Okay, so let's start unpacking this amazing system. Maybe we should begin with some foundational terms. [00:01:03] Speaker B: Good idea. A quick review of the building blocks. [00:01:06] Speaker A: Right, so first up, ligaments. These are tough fibrous bands, and their job is basically connecting bone to bone. They provide that joint stability. [00:01:17] Speaker B: The guardians of the joints, you could say. [00:01:18] Speaker A: Yeah, I like that. Then you've got tendons. These are the connectors that hook your muscles onto your bones. They transmit the muscle's force, actually creating the movement. [00:01:28] Speaker B: Power transmitters. Absolutely vital. [00:01:30] Speaker A: Okay. And then there's this stuff that's kind of everywhere. Fascia. It's like this amazing web of connective tissue wrapping around muscles, muscle groups, nerves, blood vessels. [00:01:39] Speaker B: It's the internal scaffolding and communication network. Really. It's far more important than people used to think. [00:01:44] Speaker A: Definitely. And if you hear aponeurosis, just picture a wide, flat tendon. Sort of like a sheet. [00:01:51] Speaker B: Exactly. And what's fascinating is how all these bits, ligaments, tendons, fascia, they aren't separate things in function. They all work together foundational for absolutely every movement. [00:02:01] Speaker A: Okay, one more foundational piece before we get into muscles. Anatomical neutral. This is like the universal starting point for describing any movement. [00:02:09] Speaker B: Right. Just standing tall, feet together, palms facing forward. Everything else is described relative to that position. Makes communication clear. [00:02:18] Speaker A: Perfect. Okay, basics covered. Now, how do muscles actually. Well, how do they work? How do they pull on bones? It boils down to attachments and actions. Every muscle connects in at least two places. We call the attachment Closer to the body's midline, the origin. It's usually the anchor point, the bit that stays relatively still. And the other end, further away, is the insertion. That's typically the end that moves when the muscle contracts. [00:02:44] Speaker B: So the muscle pulls the insertion towards the origin, generally speaking. [00:02:47] Speaker A: Exactly. And the movement that results, like flexing your elbow, that's the muscle's action. The biceps, rocky contracts, pulls on the forearm bone, and boom. Elbow flexion. [00:02:56] Speaker B: But muscles rarely work alone, do they? They're like a team, each playing a specific role. [00:03:01] Speaker A: Ah, yeah. The five rules. This is really interesting. [00:03:03] Speaker B: Right? So first, you have the agonist or the prime mover. This is the muscle doing the main work for a specific action, like your deltoid lifting your arm out to the side. That's the agonist. [00:03:13] Speaker A: Okay. The main player. [00:03:14] Speaker B: Then you have synergists. These are the helpers. They assist the agonist, maybe fine tuning the movement or adding a bit of force. So if your pec major is flexing your shoulder, bringing your arm forward, maybe your front deltoid or even biceps, chip in as synergists. [00:03:29] Speaker A: Got it. Helpers. What's next? [00:03:32] Speaker B: The antagonist. This muscle does the opposite action. It has to relax and lengthen to allow the agonist to work. Think of it as the brakes. If your biceps agonist is flexing your elbow, your triceps on the back of your arm is the antagonist. It has to let go. Or sometimes a tight antagonist can actually limit the agonist's movement. [00:03:52] Speaker A: Like maybe a tight muscle on one side, stopping you from moving fully the other way. [00:03:56] Speaker B: Precisely. Like a tight latissimus dorsi muscle, which pulls the arm down, could act as an antagonist and limit you reaching fully overhead where the deltoid is the agonist. [00:04:06] Speaker A: Okay, makes sense. What else? [00:04:07] Speaker B: Stabilizers. These are crucial. Their job is to hold a joint or body part steady so the agonist can work effectively off a stable base. Think about walking. Your gluteus medius muscle on the side of your hip acts as a stabilizer to keep your pelvis level, stopping it from dropping too much when you lift the other leg. Super important. [00:04:28] Speaker A: Wow. Okay, so they're preventing unwanted movement. [00:04:31] Speaker B: Exactly. And finally, mobilizers. This is sort of a broader category. Any muscle that actually produces movement at a joint is a mobilizer. So all agonists and synergists are mobilizers. [00:04:44] Speaker A: Right. So the hip flexors and extensors that actually swing your leg when you walk, those are mobilizers. [00:04:49] Speaker B: Perfect. [00:04:50] Speaker A: So it's this incredible coordination. Isn't It. Yeah. Muscles constantly shifting roles. Agonist one moment, maybe a stabilizer the next, depending on what you're doing. [00:04:57] Speaker B: It's like a dance, A beautifully complex dance. You've got it. [00:05:00] Speaker A: Okay, that's a great foundation. Now let's apply this to the torso and spine. Specifically. Where should we start? Maybe with breathing. Seems pretty fundamental. [00:05:08] Speaker B: Absolutely. The muscles of respiration. [00:05:10] Speaker A: Top of this has to be the diaphragm, right? The primary breathing muscle. [00:05:13] Speaker B: Yeah, without a doubt. This big dome shaped muscle sits at the base of your rib cage. It attaches to the inside of your lower ribs, your sternum, and even down onto your lumbar vertebrae in the back. [00:05:25] Speaker A: And the key action, when you inhale, it contracts and moves down, flattening out. This increases the space in your chest cavity, pulling air into the lungs. [00:05:34] Speaker B: Yes, that downward movement is critical. People often think it pushes out, but it's primarily an up and down piston. And because of those attachments, especially to the spine. [00:05:44] Speaker A: Ah, you mentioned this before. [00:05:46] Speaker B: Yes. It's a massive contributor to deep core stability. Proper breathing isn't just about oxygen. It's about stabilizing your trunk from the inside out. It connects to muscles we'll talk about later, like the psoas and ql. It's all linked. [00:06:00] Speaker A: Fascinating. Okay, what about the muscles between the ribs? The intercostals. [00:06:04] Speaker B: Right. The external and internal intercostals, they run diagonally between adjacent ribs. The externals are more superficial. [00:06:10] Speaker A: And they help with inhalation. Yeah, they pull the ribs up and out. [00:06:13] Speaker B: Exactly. External intercostals pull ribs up and out during inhalation, helping to expand the chest cavity. Think external inhalation, ribs out. [00:06:23] Speaker A: Okay. Externals, inhalation out. Got it. So the internals must be for exhalation. [00:06:28] Speaker B: You got it. The internal intercostals lie deeper and their fibers run in the opposite diagonal direction. They pull the ribs down and in during forceful exhalation, decreasing the chest volume to push air out. So internal exhalation, ribs in, external inhalation. [00:06:45] Speaker A: Out, Internal exhalation in. That's a handy way to remember. [00:06:48] Speaker B: It definitely helps keep them straight. [00:06:50] Speaker A: So while we're breathing, there are other muscles working silently in the background, just holding things together. Right. Especially around the spine. [00:06:57] Speaker B: Absolutely. The deep stabilizers. This raises that key question, what's actually keeping your spine aligned and supported right now while you're just sitting there listening? It's not the big moving muscles doing that primary job. [00:07:09] Speaker A: So who are these unsung heroes? [00:07:11] Speaker B: Well, deep down, running along the spine itself, we have muscles like the multifidus and rotatores. They're part of a group called the transversospinalis. These are really intricate muscles. They connect vertebrae to vertebrae spanning maybe one, two, or even up to four segments at a time. They run pretty much the whole length of the spine. [00:07:29] Speaker A: Wow. And the source used a great analogy, thinking of the multifidus, like the sheath of a sword encasing the spine, providing that deep segmental support. [00:07:41] Speaker B: That's a perfect visual. They're small, but collectively, especially the multifidus, because it's quite thick and spans so much length, they provide critical stability. They can help extend the spine slightly and rotate it to the opposite side. But maybe their most important job is stabilizing against too much rotation or shearing force between vertebrae. [00:07:59] Speaker A: Okay, deep spinal guardians. What else is deep in there? Stabilizing. [00:08:02] Speaker B: Let's talk about the transversus abdominis, or tva. This is the deepest of your four abdominal layers. Imagine it like a natural corset or weightlifting belt. [00:08:11] Speaker A: Ah, the corset muscle. I've heard that one. [00:08:13] Speaker B: Exactly. Its fibers run horizontally, wrapping around your midsection from the back, attaching to that strong thoracolumbar fascia we'll mention later, all the way around to the front, connecting into an aponeurosis called the linea alba. It also attaches to your lower ribs and pelvis. [00:08:30] Speaker A: And its main job isn't actually bending or twisting the spine, right? [00:08:33] Speaker B: Correct. This is a critical point from the source. When the TVA contracts, it primarily compresses your abdominal contents. It cinches that corset, increasing intra abdominal pressure. It's a stabilizing muscle, not a prime mover. For spinal actions like flexion or rotation, increase that internal pressure to support the spine from the front. [00:08:54] Speaker A: So TVA and multifitus are like deep partners in stabilization. Front and back? [00:08:58] Speaker B: Very much so. Foundational support. [00:08:59] Speaker A: Okay, so we've got the deep stabilizers holding things steady. Now let's talk about the muscles that actually move the spine, the mobilizers. Although I guess all muscles provide some stability, too. [00:09:09] Speaker B: Oh, absolutely. It's never purely one or the other, but some muscles have mobilization as their primary role. Before we list them, let's quickly touch on how much movement different parts of the spine actually have. [00:09:21] Speaker A: Good idea. It's not all the same, is it? [00:09:23] Speaker B: Not at all. Your thoracic spine, the part where your rigs attach, that actually has the least mobility overall. The rib cage restricts it quite a bit. You get some flexion, extension, side bending, and rotation, but it's limited compared to other Areas. [00:09:37] Speaker A: Okay, thoracic spine, least mobile. What about the lower back, the lumbar spine? [00:09:43] Speaker B: The lumbar spine has much more mobility, particularly inflection, bench bending forward and extension arching back. It also has decent side bending or lateral flexion. [00:09:54] Speaker A: But what about twisting, rotation? [00:09:56] Speaker B: Ah, that's the interesting part. Pure lumbar rotation is actually quite limited. Maybe only around 5 degrees. According to the source, most of the twisting motion you feel in your lower back area actually comes from the thoracic spine above it or even the hips below. [00:10:10] Speaker A: Really only 5 degrees? That's surprising. [00:10:12] Speaker B: It is. And the source notes it's notoriously hard to measure clinically because it's difficult to stop the thoracic spine from joining in. It just highlights how integrated spinal movement is. [00:10:22] Speaker A: All right, cool. So knowing that, who are the main mobilizers of the spine? Let's start with the abs again, but the more superficial ones this time. [00:10:29] Speaker B: Right. Moving outwards from the deep tva, we hit the internal obliques. This is the second deepest layer. Their fibers run diagonally, kind of upwards and inwards from your pelvis towards your ribs. [00:10:41] Speaker A: Upwards and inwards. Okay, and what do they do? [00:10:43] Speaker B: Well, if you contract just one side, say your right internal oblique, it helps you bend sideways to the right lateral flexion. And this is key. Rotate your torso to the same side. So rotate right. [00:10:54] Speaker A: Okay. Internal obliques, same side rotation. What if both contract? [00:10:59] Speaker B: If both sides contract together, they help flex your spine forward, like in a crunch, and also compress the abdominal contents. [00:11:06] Speaker A: Got it. So next layer out, that would be. [00:11:09] Speaker B: The external obliques, second most superficial abdominal layer. Their fibers run in the opposite diagonal direction, downwards and inwards. Kind of like putting your hands in your front pockets. [00:11:18] Speaker A: Hands in pockets. Okay, can picture that. Down and in. So what's their action? [00:11:23] Speaker B: If you contract just the right external oblique, it also helps you bend sideways to the right same side. Lateral flexion, but it helps rotate your porso to the opposite side. So rotate left. [00:11:36] Speaker A: Wait. Okay, hang on. Internal obliques rotate same side. External obliques rotate opposite side. [00:11:40] Speaker B: Exactly. That's the crucial difference. Right internal oblique helps rotate right. Right external oblique helps rotate left. They work together, often synergistically or antagonistically, depending on the desired rotation. [00:11:52] Speaker A: Okay, that's a really important distinction. Internal same side rotation. External opposite side rotation. Got to remember that. And if both external obliques contract same. [00:12:03] Speaker B: As the internals, they flex the spine forward and compress abdominal contents. [00:12:06] Speaker A: Right. And then the most superficial one, the. [00:12:08] Speaker B: Six pack muscle, that's the rectus abdominis. Its fibers run Straight up and down from your pubic bone up to your ribs and sternum. Its main job is spine flexion, bending forward like in a sit up or crunch. But it definitely contributes to overall core stability too, even though it's superficial. [00:12:26] Speaker A: Okay, abs cover TVA for deep stability. Obliques for rotation and side bending, rectus for flexion. Now what about the back muscles that move the spine? [00:12:36] Speaker B: Big players back there. The main group for extension is the erector spinae group. This isn't just one muscle, but a collection running vertically along your spine. Think longissimus spinalis iliocostalis, though you don't necessarily need to memorize the individual names for general understanding. [00:12:52] Speaker A: So the erector spinae group, what's their main job? [00:12:55] Speaker B: Primarily, they extend the spine, pulling you upright from a bent over position or arching your back slightly. They also help with lateral flexion, side bending when one side contracts and contribute a little bit to rotation. They are major extensors and stabilizers. [00:13:09] Speaker A: Got it. The big back extensors. Anyone else important back there for movement? [00:13:13] Speaker B: Definitely. We need to talk about the quadratus lumborum or ql. This is a deep muscle in the lower back connecting the top of your pelvis, iliac crest to your lowest rib and the sides of your lumbar vertebrae. [00:13:26] Speaker A: Ql. I've heard that one gets tight on people. [00:13:29] Speaker B: Very common. Its actions are key. Working together, both sides help extend the lumbar spine. But when just one side contracts, it pulls the spine into lateral flexion, side bending towards that side. [00:13:42] Speaker A: Okay. Extension and side bending. What else? It has that nickname, right? [00:13:45] Speaker B: It does the hiker of the hip. Because if your spine is stable, the QL can also pull your hip bone pelvis up towards your ribs on that same side. Like when you deliberately hike one hip up. [00:13:56] Speaker A: Ah. So it can move the spine or the pelvis, depending on what's fixed. That's cool. [00:14:00] Speaker B: Exactly. That versatility makes it really important for walking posture. And yeah, it's often implicated in lower back pain or imbalances when it gets tight or overworked on one side. [00:14:08] Speaker A: Okay, this is great. We're building a really good picture. Yeah. What about muscles that connect the spine or pelvis to the legs? There's one major one, Right. [00:14:16] Speaker B: You're probably thinking of the iliopsoas. And yes, it's incredibly important. It's actually two muscles usually grouped. The psoas major and the iliacus Psoas. [00:14:26] Speaker A: That's another one. People talk about being tight. [00:14:28] Speaker B: Very much so. The psoas major is unique it's the only muscle that connects directly from your lumbar spine. The sides of the vertebrae from T12 down to L5 across the front of the hip joint, and attaches to the top of your thigh bone. Femur. [00:14:41] Speaker A: Wow. Crossing from the spine right to the leg. So what does it do when your. [00:14:45] Speaker B: Legs are free to move? The iliopsoas. Both psoas major and iliacus working together is a primary hip flexor. It lifts your knee towards your chest. It also helps with a little bit of external rotation and adduction of the hip. [00:14:59] Speaker A: Okay. Hip flexion. But what if your legs are fixed, like when you're standing? [00:15:03] Speaker B: Good question. If your legs are fixed, the psoas major pulling from the spine can help flex your trunk forward on your femurs. Crucially, it can also pull your lumbar spine into extension or an increased arch and help with lateral flexion. Side bending of the lumbar spine. [00:15:18] Speaker A: Pull the lumbar spine into extensions if it's tight. [00:15:21] Speaker B: Exactly. This is the connection people often miss. If your psoas major is chronically tight, which is super common, if you sit a lot, keeping it in a shortened position, it constantly pulls your lower back into that extended, arched position. This can compress the joints back there and is a major contributor to lower back pain for many people. [00:15:39] Speaker A: So sitting isn't just bad for your posture. It's actively tightening a muscle that can then pull your lower back out of alignment. [00:15:46] Speaker B: That's a huge part of the picture. Yes. Understanding the psoas is key to understanding a lot of lower back issues. And just a quick note, there's also a psoas minor, but it's often missing in people. So when you say psoas, we generally mean the psoas major. [00:15:59] Speaker A: Okay. Psoas major, hip flexor, A and D, potential lower back archer if tight. Got it. So we've covered stabilizers, mobilizers, breathing muscles, the psoas. How does this all come together into what people call the core? We hear core strength all the time, but what is it based on all this? [00:16:16] Speaker B: That's the million dollar question, isn't it? It's definitely not just the rectus abdominis, the six pack. The core is really a deep three dimensional system. We need to add a couple more pieces to the puzzle. [00:16:27] Speaker A: Okay, what are they? [00:16:28] Speaker B: First, the pelvic floor muscles. These form the muscular base or floor of your pelvis. Think of them attaching between your pubic bone at the front, your, your tailbone at the back, and your two sit bones Issued to bursities at the sides, the pelvic floor. [00:16:43] Speaker A: Okay, what's its role in the core? [00:16:45] Speaker B: It provides crucial support for your internal organs, like a hammock or sling. But importantly, when it contracts, it creates an upward lift and pressure, contributing significantly to intra abdominal pressure and overall core stability. It works in synergy with the deep abdominals and diaphragm. [00:17:03] Speaker A: Ah, like the bottom of the container. [00:17:04] Speaker B: Exactly. And speaking of containers and connective tissue, we need to mention thoracolumbar fascia again. [00:17:10] Speaker A: Right. That web like stuff in the lower back. [00:17:12] Speaker B: Yes, but it's more than just passive webbing. It's a complex, multi layered sheet of incredibly strong connective tissue. And here's a wild fact from the Source. It wasn't that long ago that anatomists doing dissections basically just cut this fascia away and discarded it, thinking it was just packing material. [00:17:31] Speaker A: No way. Really? [00:17:32] Speaker B: Seriously. We now understand it's crucial. It provides structural support. It helps transmit forces between the trunk, pelvis and legs. It connect necks and envelops muscles like the transversus abdominis, the internal obliques, the latissimus dorsi, the erector spinae, the ql, the multifidus. And it's loaded with nerve endings, playing a role in proprioception and even pain signaling. [00:17:54] Speaker A: Wow. So it's like an intelligent dynamic structure integrating everything in the back. [00:17:58] Speaker B: Precisely. So now picture the whole system. The Source uses this great analogy. The core as a canister. [00:18:03] Speaker A: A canister. Like a soup can. [00:18:05] Speaker B: Exactly. Think about it. You can stand on an empty soup can, maybe even a paint can, and it holds your weight. Right. It gets its strength from having an intact top, bottom and sides. [00:18:14] Speaker A: Okay, yeah, that makes sense. So how does that relate to the core? [00:18:17] Speaker B: Your deep core musculature creates stability using this principle. You have the diaphragm acting as the top of the canister, creating pressure downwards when it contracts. [00:18:27] Speaker A: Right. The breathing muscle. [00:18:28] Speaker B: You have the pelvic floor muscles as the bottom of the canister, creating pressure upwards when they contract. [00:18:34] Speaker A: The hammock support. [00:18:35] Speaker B: You have the transversus abdominis wrapping around the front and sides, creating pressure inwards, like cinching the corset deepest ab layer. And you have the multifinous muscles providing deep support and pressure from the back. [00:18:46] Speaker A: The spinal sheath. [00:18:47] Speaker B: Exactly. Top, bottom, front, back and sides all working together. When these deep muscles co contract appropriately, they generate intra abdominal pressure. It's this internal pressure within the canister that provides profound stability for your spine and pelvis. That's true core strength. [00:19:06] Speaker A: Wow, that canister analogy really pulls it all together. It's not about individual muscles as much as the coordinated pressure system they create. [00:19:15] Speaker B: That's the essence of it. Deep functional stability. [00:19:18] Speaker A: Okay, fantastic. So just to quickly recap the main movements of the trunk and who's doing what, based on everything we've covered. [00:19:25] Speaker B: Good idea. Quick summary. [00:19:27] Speaker A: For flexion bending forward, we're looking mainly at the rectus abdominis and both the internal and external obliques. [00:19:33] Speaker B: Right. And their antagonists to the extensors. [00:19:36] Speaker A: And for extension, straightening up or arching back, the big players are the erector spinae group, the ql. And those deep stabilizers like multifidus and. [00:19:45] Speaker B: Rotators also contribute the antagonist to the flexors. [00:19:48] Speaker A: For lateral flexion, bending sideways, it's a team effort involving the QL on that side, the erector spinae on that side, and both the internal and external obliques on that same side. [00:19:58] Speaker B: Yes, a lot of muscles contribute to. [00:20:00] Speaker A: Side bending and finally, rotation, twisting. That's where it gets intricate with the deep rotators and multifidus. A bit from the erector spinae and critically, the obliques working in opposition. Internal obliques rotating to the same side, external obliques rotating to the opposite side. [00:20:16] Speaker B: Perfect summary. Remembering those opposing actions of the obliques in rotation is absolutely key. And also remembering how muscles on opposite sides of the body act as antagonists to each other. For movements like side bending and rotation, the right QL opposes the left ql, for example. It's all about balance and coordination. [00:20:34] Speaker A: What an absolutely fascinating journey through the torso and spine. We've really unpacked the complexity, haven't we? From the basic parts to distinguishing deep stabilizers from the mobilizers, and especially that core canister idea. It's incredible. [00:20:50] Speaker B: It really is. And hopefully understanding this gives you a new appreciation for what's happening inside you with every breath and movement. So maybe a final thought to leave you with next time you move. Maybe you stand up, reach for something, take a deep breath, or even just sit here listening. Try to sense that internal landscape. Consider that intricate dance of muscles, fascia, bones, all working together. How does knowing this change how you might consciously support your body? [00:21:14] Speaker A: That's a great point. It's not just abstract knowledge. It's about connecting with your own incredible physical self. Thank you so much for joining us on this deep dive today. We hope you feel a bit more connected to and amazed by the engineering marvel that is your own torso and spine.