Week 3 Wednesday Anatomy PDF

All right, so let's pick up where we left off. So we left off yesterday talking about the ear and some of the structures that help us out with balance and the sense of hearing. So now we're going to travel into the neck, so we are going to talk a little bit about skeletal anatomy. We're going to tal...

All right, so let's pick up where we left off. So we left off yesterday talking about the ear and some of the structures that help us out with balance and the sense of hearing. So now we're going to travel into the neck, so we are going to talk a little bit about skeletal anatomy. We're going to talk about muscles in the area, some viscera, and that's also right here, the one thing to keep in mind. This picture shows it pretty nicely there's a lot of different types of structures that are jam-packed into this small area. So I mentioned musculature, but we also have the thyroid gland, we have our brachial plexus starting to emerge from the spinal cord, so we have a lot going on. Add Clip 08:07 So, starting off here with skeletal landmarks, we're going to hit some of the bones and focus on the cervical vertebrae. We'll pick up with the rest of the vertebrae next week when we start to dive into the back, which is part of the second unit. So here we have mentioned already our hyoid bone. So let's start there. So let's start there. In this picture we see our little hyoid bone floating, no skeletal attachment, but we'll see today a lot of muscles attached to it. We have our sternum, which we're only seeing a piece of the sternum in this picture, since we're only focused on the area of the neck. We're just thinking about the superior aspect of the sternum, which is called the manubrium. So that's the very top of the sternum. And then, just a reminder, clavicles are going to be attaching on either side of that manubrium. So we will see clavicles as a little bit of a border and attachment site for some muscles. 08:55 So we mentioned cervical vertebrae. We will do the whole spiel about vertebrae next week. I'm just going to kind of get through the need to know for the cervical region. But one thing to keep in mind each region is going to look a little bit different. So we are just focused on this region right here and then we'll talk about unique features to each region. The thoracic lumbar, sacral that next week. 09:09 So we got to start off with C1. C1 is going to be the atlas. So this is the first cervical vertebrae. So we named the shorthand of the vertebrae, as always for the region, and the number starting superiorly, working our way inferiorly. So the atlas is pictured over here and one way to pull it out when you're working with your bone box and lab. It looks like a ring. There's not a whole lot to it, it kind of looks like a circle. So since it is the first vertebrae up. 09:32 Its main function is to articulate with the occipital bone, so that's why it's going to be shaped the way it is, so to go through the and that's in part because of the ligaments not being as large at this point, because we're just coming from the occipital bone, so it's just a little bump on the back side of the ring. We do have nice articulating surfaces. So what are shaded in blue here? Whenever you see blue in these pictures it's indicating there's an articular surface, meaning that's where another bone is going to touch and create a joint. So we have nice special piece of cartilage there to help create that joint. So when I circle there, those are the superior articular surfaces, so they will connect with occipital condyles. That's out here, nice bumps on the bottom. 10:22 So the next structure we have transverse foramen. So foramen meaning whole, transverse meaning to the sides, and so in the cervical region we have transverse foramen. You can see them nicely on the sides here. And what's going to go through the transverse foramen? Vertebral artery. The next structure on the list goes hand-in-hand with that. We have the groove for the vertebral artery, unique just to the atlas in Z1. What ends up happening is the vertebral artery is going to go through our transverse foramen as it comes up the cervical neck and then it actually I'm going to do a terrible job depicting this lays over the groove and then goes up into the foramen magnum in that area. So it lays over that nice flat portion on either side here. So that's the groove for the vertebral artery and I think as soon as it's going through that foramen magnum it's starting to converge to become the bacillar artery. Oh, what I think is the Atlantic portion In that region. Yes, yes, yeah, I'm sorry I was misunderstanding your question. Yes, all right. 11:21 So then I have the joint here we should be aware of in this area. So we have essentially the occipital bone on the atlas, properly called the lanooccipital joint. So where these two bones come together we associate the motions of flexion and extension. So moving in the sagittal plane, not to say this is the only place this movement comes from, but at this specific joint that's the biggest movement that we get. So oftentimes we say that motion of nodding, yes, is initiated here from that lano-occipital joint. And then also for the action here of lateral flexion, you just get a little tilt at this joint going to the side, so I think touching your ear, your shoulder is lateral flexion. Just a little bit comes from this joint. And for actions, we're going to talk a little bit more about actions today. As we get into other musculature, I will do my best to kind of explain the motions. But if this is totally foreign to you flexion extension, all that I would make sure to go back, hit a YouTube video, refresh yourself on these actions. All right, so then, last thing, as we go through major joints, we'll talk about what's stabilizing the joint, aka what's holding things in place here. 12:17 So we have the anterior and lanoac posterior one. So it's not a ligament. Ligaments are the thicker structures that connect bone to bone. Whenever you see membrane, it just means it's thinner. It's not quite warranted to get that name of ligament, but it's serving the same purpose. So it's helping to connect two bones and stabilize the area. 12:34 So, specifically for thinking of the anterior inlino-occipital membrane, that's going from foramen magnum, so from the occipital bone. Since it's on the anterior side, it's going to be attaching to what's called the anterior arch. For the posterior, one similar concept here we're going from foramen magnum and this time we're going to be going to that posterior arch. So first join up in our vertebral column. So for the anterior, it's the condyles that are titrating and for posterior, it's the bridge of the frame and magnum. I would think both of them. Frame and magnum. It's not necessarily connecting the joint itself, it's around the joint. Yeah, so helping with displacement, and not just the anterior, it's more posterior, connecting the joint itself, it's around the joint. Okay, yeah, so helping with displacement and not just the anterior and posterior, exactly, yep, all right. 13:36 So moving down, next up we have C2, which is called the axis. So here with C2, if you're in your bone box and lab how you can pull this one out. So it looks like cervical vertebrae. It's got the extra holes on the side. But the unique part to C2 is going to be the dense, sometimes called odontoid process, and that's going to be sticking up on the anterior side. It looks like sometimes it's nicknamed the thumbs-up process. It's sitting on that side and essentially that dense is going to stick up and through the foramen of the axis. Oh, I think I have To hit our list of structures to note here. So for C2 we start to look more like a typical cervical vertebrae. We have our spinous process on the posterior side that's going to serve as a nice attachment point for our treatments. 14:15 We still have these superior articular surfaces. This time what's above it is going to be C1, so that's what's going to be sitting on those surfaces. And whenever you see the term facet, it just means it is a flat articular surface and then we have our transverse foramen on those sides, vertebral artery again flowing up through here. So now if we're thinking of C1 articulating to C2, that is our atlantoaxial joint and the main motion that's coming from this joint. Again, think of C2, that thumbs up sitting with C1. The C1 ring just goes around. It's almost like a ring toss. It goes onto that dense process and then you have C1 and C2 rotating on each other. So now you can do that, go ahead and rotate side to side. 14:56 So in this area, to make sure we are stabilizing so our dense process doesn't move forward into our spinal cord, let's say, or out of place, we have transverse ligament, we also have alar ligaments. So your transverse ligament and you have a few transverse ligaments in the body, so specifically here with the landoaxial joint is going to be running in this direction across the dense process and it's simply going to wrap around the dense process and then attach to C1. Process and then attach to C1. The interreligion is a little bit different and we have these occurring bilaterally. So they're going to connect the dent to the foramen magnum. So picture them going more in an upward orientation. It's a little bit of a better picture here. So at the bottom we have C1 going through C2. So here's the dense drawing a green dot on it and so we need to pay attention to that alar ligament. So wrapping around that, going from the dense process up to the foramen magnum, this picture I will say with the alar ligament, that purple ligament a little misleading, it looks like it goes to the articular surfaces here. It goes up to the foramen magnum and then the transverse ligament is the yellow one here. So just wrapping around that DENS process, making sure DENS doesn't move forward, yeah, so think of it almost like an oblique orientation coming from Dens going. It's a little bit of a better picture here. So at the bottom we have C1 going through C2. So here's the Dens drawing a green dot on it and so we need to pay attention to that ailer ligament. So wrapping around that, going from the dens process up to the foramen magnum this picture I will say with the alar ligament, that purple ligament a little misleading. It looks like it goes to the articular surfaces here, it goes up to the foramen magnum and then the transverse ligament is the yellow one here. So just wrapping around that dense process, making sure dense doesn't move forward, yeah, so think of it almost like an oblique orientation coming from dense going straight up to foramen magnum In the top picture. 17:16 This top picture is a little bit of a strange view. Here We've got the bottom of the skull and then we're getting into cervical vertebrae, so here's the foramen magnum and then, if you look closely here, here's the collar lipid. It's kind of in that V direction on either side. Can you go back and go over the dens and spinous process? So the dens and spinous process Could go over the dens and spinous process. So the dens and spinous process. So we've got the dens or odontoid process sticking up on the anterior side, spinous process on the posterior side. So we've got some. 17:51 So the AR attaches down to the occipital condos. I thought you said it should be for Raymond Magnum. Yeah, let me double check my picture here. Yes, that is for Raymond Magnum. Here, raymond Magnum Going upwards. My apologies, magnum, you will also have joint prosections in the lab tomorrow. So we'll see the bottom of the skull, kind of similar to this top picture. We'll see this cross-section and we can find some of these ligaments here. 18:22 All right, just to note, especially in this C1, c2 occipital area there's a lot of ligaments stabilizing things. So just focusing on the ones that we have listed here, that's the goal, all right? So then just to quickly address the rest of the cervical vertebrae, since we are talking about the neck, once we descend past C2, these are typically called the normal or typical cervical vertebrae. So now we're talking about C3 to C7. Those are the rest of the cervical vertebrae. They all look very similar. For the most part, they all have these processes that are listed here. And then, just a reminder as you kind of descend down, c3 is going to look a little different than C7 because you're transitioning to different areas. All right, so if we were to pull out a typical cervical vertebrae, we should be able to ID these things. 18:59 I think at this point we've got those transverse foramen, the bifid spinous process. So that is the spinous process. The thing with the cervical region that's a little unique compared to thoracic lumbar is that your spinous process forks out and so it's called a bifid spinous process because it almost looks like there's two, and this picture shows them pretty well here. So if you look at each of them, they're spanning out. They're going to be a lot thicker. Fun fact, since we were talking about pharynx and all of that, you can have a bifid uvula. So bifid just means that structure is splitting. Hang out Google that, see some fun pictures. 19:35 All right, and then the last process, again unique to cervical vertebrae and very unique to C3 to C7, so C2 and C1 don't properly have these are the uncus or the uncynate process, and this view, since we're seeing the superior view. It's a little bit hard to picture this, but what ends up happening is the lateral sides of the bodies, that big portion where we start stacking our vertebrae. The lateral sides start to flip upwards, extend up just a tiny bit, creating this shelf almost in this agile plane, and the purpose of that is going to be just to help stabilize the vertebrae and help prevent any slippage. So that's C3 to C7. Just to confirm the little blue part where that's what the opposite of the first section is. Yeah, just at the end, and that blue is kind of giving you an indication. You're going to have another bone touching there and we'll ID that, I think, next week when we do the joints in the back. So C7, even though it's the long-term process, it's still considered the bifid one. Yes, so my question for us here just a quick ID1, so click on C2. So we'll circle back to C3 to C7, especially next week We'll ID a few more things. Talk about some other joints in the area, but getting us the basics for this unit, okay. 21:02 So C2, hopefully this is a quick, easy clip. So we're thinking about atlas versus axis, axis being C2. It's going to be on this right here. So we've got the dens in the back. We've still got transverse foramen. We've got that bifid spinous process. To the left we have a nice circle or ring thing. So we have the posterior tubercle, not a full-on spinous process. We've got those nice superior articulating surfaces. Yes, yeah, yeah. 21:31 So C2 sits on C1. And tomorrow when you're in lab, piece these things together, rotate them, see how they move. And we do have full vertebral columns in lab 2 you can play with and move around. So C2 sits on C1, and then transversely holds that dense back Sits on C1. Yeah, so C1's first. So what I mean by that is C2 goes around C1. So C2's got the dense process and then loop C1 over it, c1 then C2. C1 sits on C2? Yes, okay, yeah, c2, the dense fits through C1. Yeah, everyone, okay. Does C1 have a loop process? No, c1 doesn't, because it doesn't even have a spinous process. C2 does start to have it. 22:11 And then what I'd like you to focus on is that's the unique characteristic for the cervical region. So you will never see bifid on a thoracic vertebrae, and that has to do with ligaments attaching. You have a really big ligament running down the back of your neck, just your neck. So you need a wider point of attachment there for it. It works out. So play with arrangements in our own lab. So we're going to skip a beat here. 22:34 So, moving on from skeletal anatomy, we're going to start to talk about musculature. But before we do that, we have to address the topic of fascia, which we really haven't talked about yet. And we're not quite getting into histology here in this course. But if you remember way back when you learned about epithelial tissue, connective tissue, muscular tissue, so does fascia. So fascia is composed of connective tissue, and I kind of give you an idea here of what types. Um, loose, areolar Don't focus too much in on that. If you really remember your histology, maybe that will help to piece things together. 23:03 So what we do need to know when it comes to fascia. Fascia is going to be this tissue that typically wraps and helps compartmentalize certain tissues. So, for instance, if you guys were dissecting out our donor, a big battle would be getting through all the fascia. You get skin back, but then you have all these layers of fascia wrapping and grouping structures. So we have different names for fascia depending on where it is in the body, what level it's at, what it's actually wrapping around. 23:23 So the first one up here we need to know is superficial fascia, and there's a ton of names for this per typical anatomy. So superficial fascia is also called hypodermis. Remember your skin layers? We probably talked about epidermis, dermis, hypodermis the hypo below the actual skin is technically fascia, also called subcutaneous tissue, or sub-Q for short. So what this is. If you look at our donors, at wherever skin has been peeled back, usually you'll see the skin, but then you can see this yellow layer there where there's some fat, and then there's going to be some connective tissue. That's all hypodermis or superficial fascia, so a lot of fat in this area, especially depending on where you are in the body. 23:56 So then we have deep fascia. So, like the name implies, we're going to be heading deeper down into the body and typically deep fascia is going to be what actually wraps around certain structures and kind of bundles and organizes things. So this type of fascia is going to be a lot denser, and the top picture is a good example of what that dense fascia would look like. You can actually peel it away. You still see a little bit of a spider web appearance, but it wraps around bundles of tissue. All right. 24:22 So for us in the neck here we have a few wrappings of fascia we need to talk about. So this category that we're talking about here is deep fascia, so it's not the subcutaneous right underneath the skin, so it's going to be a little bit thicker, a little bit stronger, a nice framework for some structures to sit in. So the most superficial layer in this area when it comes to deep fascia, we have veins for every piece of fascia in the body. It's kind of crazy. There are actual whole societies that devote their studies to just fascia in the body. I remember last year they were having a big meeting that was being advertised to even our anatomical societies because they were thinking of renaming certain fascial structures. It is intense, in depth, there's a lot of it. 24:57 So here for us in the neck, the three layers we have to know within the deep fascia we have the first investing fascia. So out of these three it's going to be the most superficial and this one is going to wrap around a few structures. So for us in the neck, where we're going to see it here is going to be around the sternocleidomastoid, around the trap. Those are some major structures that it's going to help to wrap and enclose. Another layer that we have is called the pre-tracheal or also bucofaringeal fascia, and that term pre-tracheal is giving you a little bit of an idea of what it's actually going to wrap around. So it's going to wrap around the trachea. What comes with the trachea, what's sitting on the trachea is also the thyroid gland, and then what's right behind the trachea I know we haven't talked about these things quite yet is the esophagus. So just wrapping around those structures, that's the pre-tracheal fascia and I'm giving you an idea of the height here, less important for us to know exactly where it starts and ends, but it's starting in the area of the highway and then going all the way down to the thorax. This one actually eventually goes down even further, down to the heart and extends out. So then the last layer that we need to be concerned of is the pre-vertebral fascia. So I think it has vertebral in the name. So this one's going to be a lot more posterior, wrapping around the vertebral column and some muscles we'll talk about today that are sitting anterior to the vertebral column. So if you removed your trachea, esophagus, all of that, you would have muscle sitting behind there. Those are the pre-vertebral muscles. So this fascia wraps around those muscles and the vertebral column. So we keep saying wraps around. 26:24 So one of the functions when it comes to deep fascia, wrapping around structures, is to make sure we're compartmentalizing. Whenever we compartmentalize, we pretty much put up boundaries. That's a nice way to stop spread of infection. So always a cause to separate cavities and structures. Another reason why we have these investing layers or deep fascia layers is to help out with movement in the area. So, especially the neck, we have all these structures jam-packed. So if structures were just kind of hanging out and around, but as you moved around there might be some catching. It wouldn't be this nice gliding movement of, say, your carotid artery against some of your pre-vertebral muscles. So by wrapping everything we're making sure everything's going to glide nicely against each other, reduce friction. 27:10 So one other sheath is going to be the carotid sheath. We've been alluding to this a little bit with our cranial nerves and structures. So the carotid sheath is the fascia that's going to wrap around the listed contents here. So in our neck on either side here we have the common carotid artery, which is where the name comes from. We have right next to our internal jugular vein, and then we have cranial nerve number 10, our vagus and some deep lymph nodes. In this area structures all get packaged together. So in order to see your common carotid artery you've got to cut through the sheath and peel it back. So in lab I have opened up some carotid sheaths. We'll see those and you'll get a glance at those contacts there. So typically whenever we have a major artery the vein is going to be stuck to the back of it and usually there's a piece of fascia wrapping them together. 27:49 Last thing up here related to the fascial wrappings here, a space we have to address which is the retro pharyngeal space. So retro is defined. It's going to be behind the pharynx. So this particular space here and let me point it out in this picture I pulled this picture it's not from your textbook but it's a nice way to visualize it here. So think about how you have your trachea. Right behind your trachea you're going to have the esophagus. Right behind your esophagus you're going to have a retropharyngeal space. This is a potential space, meaning typically it's going to be closed. Structures are going to be pressing on each other, but if, let's say, a structure were to be pulled forward, there's a space that could develop there. 28:25 So why this space is on our list of things to know about. This is going to be an area where we are connecting the pharynx down to getting into our mediastinum, thinking in the area of the heart, deeper structures. So this is going to be a route for infection to spread. So, for instance, if someone's having dental work done, if there's an infection, this is a potential route for that infection to spread downwards. So this space I'll pull out again this week our bisected head. You probably didn't even notice this space, but it almost looks like the esophagus on those bisected because, especially on those heads, it's been pulled apart a little bit and you'll be able to see how big that space actually is. 28:59 All right, so then getting into the fun stuff. Here we have some musculature to talk about. So before we get into this, what do we actually need to know? Here we're going to walk through some of these muscles. Innervation is always going to be a big piece for us to know. It's going to talk about that. We're also going to talk about actions. It's another big piece for us. You do not need to know skeletal attachments, so do not worry about memorizing the skeletal attachments. I've put them here in our grid. So if you are someone who really likes to visualize why it is moving in this, it all relates back to where it's actually attaching, but you do not have to know those. Typically in our class, you will never have to know attachments. It's the innervation and the actions and I should say ID for most of them. All right, so let's talk about this. 29:42 We've got three muscles to kick us off here that help to act on the neck. The first one up is platysma. I don't even have attachments here. Platcia it is very thin. It's the only action that's really of value that comes from the platysma you can see here it helps to draw or the skin of the neck. So especially if you're protracting your mandible and you clench the skin of your neck, that's all the a whole lot. I would associate platysma with your muscles of facial expression, so acting on the face, to kind of recognize. It has the same innervation here at number seven, facial nerve. So the next one, a larger muscle here we talk about it a lot, especially with creating borders in the area of the neck. 30:29 We've got the sternocleidomastoid, so named after areas where it's attaching here we know it's going to be innervated by number 11 here, spinal accessory, the actions. It does have a lot of actions. So to kick us off here, when we see some of these larger muscles, especially existing in areas of body like the back or the neck, typically they are going to have unilateral and bilateral actions, meaning what can happen if just one side of the muscle contracts versus what happens if both sides of the muscle contracts. So that's the uni versus the bilateral, Some terms that we are going to see here just to define them. One thing we will see is ipsilateral versus contralateral. So ipsi means same, so same side, if we're talking about rotation to the same side. What that implies is, if we're talking about the right sternocleidomastoid and let me make sure I get this right right one is going to help with axilateral flexion or lateral flexion. So the right one is going to help to laterally flex to the same side. If we were talking about a muscle that does, let's say, contralateral rotation, we're talking about the right muscle. It's going to rotate to the opposite side, to the left side. So let's walk through sternocleidomastoid here. If we're just talking about one side of the body here with sternocleidomastoid, this one's going to help out with lateral flexion, so think, touching your ear to your shoulder. It's also going to help out with looking to the opposite side, contralateral rotation. So that's unilateral action. 31:48 If both sides of the sternocleidomastoid are working, they can both help to extend and think extension, for the neck is typically looking up or back a little bit. We're going to do extension all the way at the top joint and lanoaccipital joint I'll show a picture here in a second of what that looks like and then it can also flex the rest of the neck. So flex downwards, and this has to do with its orientation here. So going from sternum clavicle to the back of the neck. There, all right. So let's see what does this look like? So it can extend the top of the spine, it can flex the bottom of the spine. So this is kind of a picture that shows us that a little bit. So your top joints will act a little bit differently with the line of pull of this muscle. So you can get extension at the top, flexion at the bottom and you can also reverse that. But in addition to like drawing so you can have the two together, typically not just straight flexion or extension, so just extending the top, flexing the bottom. So that would be protraction, retraction. It's really slight when it comes to these cervical joints. 32:53 So then let's hit the trap. Here we got the trap. Trap. So trap we'll see on our donors is that nice diamond shaped muscle because it's so big. It has different fiber directions. So it gets broken up into upper, middle and lower trap so we can see the different actions for the regions here. So now we're going to start to talk about action on the scapula. We'll circle back around to the trap too when we get to the upper extremity. We'll do some muscles with that. 33:11 For now just to go through trap quickly. We're talking about it because it does have an approach in the neck here and helps to create borders in that upper trap. The upper trap is going to help to elevate and then also upwardly rotate your scapulas. So that's the important piece for us right now. Just hit the other one. So middle trap is going to pull the scapulas together. That looks like retraction, and then lower trap is going to pull down on the scapula, so depression, kind of lowering your shoulders. If both sides of our trap are working, like specifically the upper trap, they can help to extend the neck, along with other structures we'll see. And then if just one side of the trap is working, it can help out with lateral flexion, c-lateral flexion. 33:55 So the next pit stop here for us is to talk about regions of the neck which just from this picture alone you can see it almost looks like a mosaic painting. Here we have a lot of different triangles and areas of the neck. We like to describe things as squares or triangles and talk about content and borders, especially when it comes to clinical practice. If you have an idea of borders and associated landmarks, you can kind of find your way to structures, for instance if you know where the laryngeal prominence is, and then you go to the side you can find the bifurcation of the carotid artery. So knowing these landmarks helps with palpation and different techniques. 34:30 So before I pit forward, let me just point out two muscles. So two muscles we're really not going to get to know individually but are going to be borders for some of these triangles. So the bottom picture here let's go with that one. The bottom picture. We have sternocleidomastoid. I'm going to draw a black line on Huge border for us when it comes to a lot of triangles. 34:41 One other one we've already talked about is that trapezius muscle. So coming from the occipital bone it goes down to the catapult in this area. So we see them in the area of the neck. That we're not going to talk a lot about, but I just want to point out. So we have an idea of why they are setting up some of these triangles. One is going to be muscle sits let me draw a line on it Digastric muscle. So it almost looks like it creates. 35:03 This V that I drew in has two bellies, two different orientations. We're not going to get that deep into it, but just to recognize the digastric is below the mandible in that area. One other muscle we'll see helping to create some borders. So I just want to point out it's going to be the amohyoid. It's my favorite muscle. So the amohyoid is going to be a muscle that swings down in this area. It's got a pretty fun orientation, drawing an orange line on it. So it goes deep to the sternocleidomastoid Same thing as two bellies, has two different areas. One will see more anterior and you can see here inferior belly is being pointed out down towards the clavicle. It actually goes all the way down to the scapula. It has this crazy orientation. That's going to be another border that we'll see. It's called amohyoid because it starts at the hyoid bone. So we'll talk about those along the way. 35:50 How about, before we get into our triangles here, we'll take a bathroom break and we'll come back and we'll tackle these? Should I explore a little bit more? Thank you, just a quick question to come back here. So we have our cervical burn ray. If this were sitting out in front of you, let's say on a lab quiz, you should be able to tell it's cervical. We have the transverse foramen. We've got a really nice bifidus minus process here. 36:39 The question is to ID an uncinate process or an uncus. So if you look in on the sides of the body. So these two red dots would be correct here for the uncus or the uncinate. So then, when the next body stacks on top of it and you do have the little intervertebral disc, but it helps to create a little bit of a wall to the next vertebrae, yep, yeah. So picture the next vertebrae stacked on top, so it's actually going to touch the next body of the next vertebrae. So then that disc is really held tight and then the next vertebrae too has more stability, exactly, yeah, sitting right on the body there. Yep, all right. 37:18 So coming back to triangles, all right, so let's get into this. We have two big triangles in the neck. We've got a posterior triangle and an anterior triangle. The thing we're going to focus on is the general area, and I give you the borders here. And then what are we going to find in this area? So here for the posterior triangle, let me map it out on our picture. Here we have the border of the upper trap, so I'm just going to paint that in. We've got sternocleidomastoid, that's the SCM, and then we have the clavicle making our third border here to create a triangle, so in the posterior triangle, and what I would think is behind the sternocleidomastoid. The rest of the triangles we're going to talk about will all be in front of the sternocleidomastoid. 37:52 We have quite a few contents in this area. We've got some muscles popping out to talk about scalenes. It is a big group of muscles. I shouldn't say big or not physically big, but an important group of muscles. Maybe you remember levator scapulae that also peaks out in this area, and a muscle we won't talk about a ton, but this is a neck muscle on the posterior side. Splenius helps to extend the neck. So we're seeing some muscles. I would focus on scalenes here. 38:16 Eventually, when we come around to talk about brachial plexus, we'll do that as we go on further through the units. Brachial plexus is a huge group of nerves that are going to exit the spinal cord in this area and then course down and feed the upper extremity. So we'll look at your ulnar nerve or radial nerve. Those are all coming from the brachial plexus that pops out in between your scalings. So brach probably the most important content to remember right now brachial plexus. In the posterior triangle You're seeing some nerves being pulled aside. In this picture You're not getting a great glimpse of the whole brachial plexus, but they are right there. We'll see them in lab tomorrow too. We have a few donors whose talons are dissected out and then, essentially, if you pull two of them apart, you see the whole plexus coming through. And then other contents just to be aware of here External jugular. 39:04 External jugular is pretty lateral and pretty superficial. It actually goes over the sternocleidomastoid, and then what emerges with the brachial plexus is going to be the subclavian artery. It's right there with it. So the brachial plexus scalenes. So then, if we move to the front of the sternocleidomastoid, we have the anterior triangle. So, note, the anterior triangle is going to get split up into all the rest of the triangles. You're seeing, we're going to do a few of them, not all of them, but I think a common trap here is to forget about the general anterior triangle and focus in on all the rest. Don't forget, though, this is a triangle. So borders here we've got sternocleidomastoid, we have the mandible creating another border. Here we've got the top of the sternum, the mnubrium, and we just make an invisible line down the midline of the neck. So this is essentially the partner to the posterior triangle. This is where we have a lot of contents, though, so it gets broken down even further. So before we get to those smaller triangles, we pointed out the digastric and the amohyoid already. 40:04 One thing to know about. You do not have to know about the individual muscles here. I just want you to know the name of these groups superhyoid versus infrahyoid muscles. Already the name is telling you superhyoid is going to be above the hyoid. They are attaching to the hyoid and then the infrahyoid are going to be below the hyoid. So when it comes to suprahyoid, the function we should be able to associate with these is going to elevate the hyoid and what that translates to it's going to help you with swallowing. Same thing with infrahyoid muscles, but now we're going to depress the high wave. So you do not need to know the individual muscles that make up these groups. 40:52 Tomorrow in lab I will say I have a few uncovered, so you will see some of these, and that's why you won't be able to see your trachea right away. You won't be able to see the thyroid gland because we do have these muscles covering that area. Be able to see your trachea right away. You won't be able to see the thyroid gland because we do have these muscles covering that area. Do they both help with swallowing, or just the infrahyoid. They both help with swallowing. Yeah, any movement of the hyoid is going to help with swallowing, all right, so now we've got a little bit about our hyoid muscles, let's hit a triangle. 41:20 We've got the submandibular triangle, so think the area right beneath the mandible and the mandible is going to be a border here and the other border are just the two bellies to our digastric. So this is the very top, superior, anterior portion of that anterior triangle. What we have here, submandibular lymph nodes, and we've got the submandibular gland. Don't memorize it, just think the names are associated. It's in that triangle. Other things we do have here. So we have facial artery and vein, so these are going to be out in lab tomorrow. We'll see facial artery and vein and where you're going to look for them is coursing right at the bottom of the mandible. So that is why they're located in this triangle. Hypoglossal nerve, I think it's going to the bottom of the tongue. So thinking where that root of the tongue would be, where that area is, that's going to land it in this triangle. 42:07 So the next one up here we have the submental triangle. Okay, so submental, teeny tiny, so submental is going to be hyoid. You can see that in this picture. Right here We've got just the anterior digastric and then the imaginary midline of the neck. So right on the front side we've got submental mental meaning, shin area and the one thing to know here submental lymph nodes. We have these congregations of lymph nodes. So this is an area for some of the superficial lymph nodes. This is the most important triangle for us. In the anterior triangle you can see it's got a lot of content but we'll work through it. 42:42 So we have the carotid triangle. So here if we're going sternocleomastoid, we've got part of the amohyoid and then we have part of the digastric. Here we're looking at that orange space. So this is the one where we have the carotid sheath. So, if you can remember, we have the internal jugular, we have the common carotid artery which is going to branch. We'll have the bifurcation into internal and external branches. What's our other content of the carotid sheath? Vagus, it's going to be vagus. So that's the carotid sheath. 43:16 Hypoglossal we talked about going to that bifurcation of the carotid. So if you can associate that, we have a guest appearance from the nerve kind of floating through in the area. It's not a proper content of the sheath. And then the last one we have not talked about is ansa cervicalis. So ansa cervicalis is a group of nerves. It's a portion of the nerve network coming from C1 to C3 nerve roots. Why we are seeing it in this area is that it helps to innervate some of the hyoid muscles. So it will be passing through this area of the carotid triangle and the cervicalis will innervate some of the hyoid muscles. So with these triangles, what I would try to do is make sure you're associating the names of the structures and if you can see the patterns here, the carotid sheath less memorization, more understanding. It's going to be a lot easier on your brain. 44:09 The last one up that we have is the muscular triangle. So now what we're seeing is a little bit of a different view, a little more superficial. This is straight at the midline of the neck here. So we're going to draw a line through that midline to create some of these triangles. We've got superior belly of the amohyoid and then we also have the sternocleidomastoid, so this is gonna be a triangle right here. So what's important about this triangle? This is where we have some of the viscera, so we're taking the glands on the anterior side, so thyroid gland, what's attached to the thyroid gland. We'll see this in one moment. Here We've got the parasympathetic glands, since we're only going up to the hyoid itself. That's where this triangle ends. We also have intrahyoid muscles. So the muscle you're seeing right here, this is an intrahyoid muscle. So those are our triangles. 45:01 So questions you might see, you'll see a lot of content where you're going to have questions. So, so, similar to this, the facial artery, facial vein, are located within which triangle? So again, we have posterior triangle, we have anterior triangle. You're not seeing either of them listed here. What we have listed are the smaller triangles of the anterior triangle. We're thinking of facial artery and facial vein. They're running at the bottom of the mandible, so they're in the submandibular triangle. Submental triangle we only have submental lymph nodes going on there. Carotid triangle we have that carotid sheath. Muscular triangle we have the viscera, the thyroid gland. We're thinking posterior triangle. We're thinking plexus, brachial plexus, all right. 45:55 So then, getting a little bit deeper, we have these pre-vertebral muscles we mentioned with the fascia. So just to orient us for one second here, this picture so we're seeing the occipital bone at the top here and then we're seeing the vertebral column come down. We're seeing some of the ribs here on the lateral sides. Essentially, what happened is they removed everything, so you're not seeing the trachea, for instance, the esophagus. All of that was removed. So that's where Fisbein comes in. 46:21 Pre-vertebral muscles. So I have listed here what we should know about these pre-vertebral muscles. The first two that typically get grouped together here are longest cavitus and longest coli. So these are going to be very similar. We have longest cavitus and then longest coli. These are the ones that are directly on front of the vertebrae. So one key to remember if they're in the front-oriented, located right in front of the vertebral column, they're going to help with flexion. If we're looking at a muscle that's on the backside of the vertebral column, that's going to help with extension. 46:57 What also gets grouped into this category of anterior is the anterior scalene. We have three of them. We. What also gets grouped into this category of anterior is the anterior scalene. We have three of them. We'll see the next two on the next slide, so it might make sense to group these a little bit differently in your notes. We have the anterior scalene right here, so you can see all three scalenes in this picture fanning out. So they're going to be looking a little bit more laterally and they go down to the ribs. So anterior one just goes down to the first rib. 47:18 What we need to know for the neck is that it helps out with lateral flexion. So specifically, ipsilateral flexion, ipsilateral flexion. Let me hit the other scalenes. So we also have the middle and posterior scalenes. We've got a little scalene here, so they're hiding right in this area here. What's happening posterior is we're starting to see the glimpse of the superior proximal attachments of some of the other muscles in the area With our scalenes, I think. 47:54 Ipsilateral flexion, they attach to the first or second rib, depending on which one we're talking about. So you do help to pull up a little bit on the ribs. Lesser importance for us now rib, depending on which one we're talking about. So you do help to pull up a little bit on the ribs. Lesser importance for us now. We'll come back when we talk about ventilation, respiration with these muscles. But the other thing with the scalenes don't forget, make sure it's in your notes brachial plexus comes out in between the scalenes, so it's something we're missing in all these pictures. So our levator muscle we're seeing it peak out in this area, but it goes down to our scapula, so we're seeing it in this posterior triangle area Not a focus for us right now because we're not talking about the upper extremity, but it helps to elevate the scapula. 48:30 One other muscle I would hone in on here is spleenus capitis. So spleenus capitis is immediately deep to the trapezius. So if we peel back trapezius, we'll get a glimpse of this tomorrow. We've got spleen and cactus. It runs on this opposite fiber diagonal down to the vertebrae. So this is going to help us out. It's on the back side of the vertebral column, so it's going to help us out with extension when both sides are working, and then, if just one side is working, it's going to help us out with ipsy lateral flexion it doesn't say ipsy or contra it's and then innervation. 49:04 You don't have to know any special nerves. I just put the note down here in case you're searching. It is coming from rami of the cervical nerve roots, which is a really nondescript way of just saying immediately from the spinal cord. We have small branches that go directly to these muscles, so don't worry about any specific nerves. So then last portion up here we do have to kind of circle back to the viscera. We've been mentioning it with muscular triangle. 49:26 So let's talk because there's no other time we will talk about these structures the thyroid gland, parathyroid glands. Once you peel back those infrahyoid muscles, that's when you start to see the trachea and you'll start to see the thyroid gland so down in this bottom picture. Here you have the pink thyroid gland. What ends up happening is there's two lobes on either side, one lobe, I should say, on either side, and then there's a little bridge that connects them in the middle. That's the isthmus. Isthmus literally means bridge, so it's used with a lot of organs, a lot of terms in the Nave. But we should know the function of the thyroid gland. 49:56 The thyroid gland is going to produce a few different hormones. So I have here listed T3 and T4. T3 and T4 generally are known as metabolic hormones. So if someone does have an issue with their thyroid gland, it might be affecting their metabolism in terms of either it's increasing their metabolism they're having issues at that end of the spectrum or it's decreasing their metabolism. But one other hormone that's secreted here is calcitonin. Totally different. Calcitonin helps to decrease blood calcium levels. So what that means if you have just eaten a meal that's rich in calcium, you need to deal with all that calcium. You're going to take the calcium out of the bloodstream. You're going to put it into tissues that need it. So the thyroid gland is going to help with that. Calcitonin will shuttle calcium into your tissues. 50:38 If we were to peel back the thyroid gland and look at the posterior side of it, we see these little nodules in it. Those are the parathyroid glands. They don't look like anything particularly special. Usually you have two or three pairs on the back side. The one function of the parathyroid gland is that it has its own hormone, just called parathyroid hormone, and it's going to be doing the opposite of calcitonin. So this time it's going to help to increase blood calcium levels. 51:02 So let's say you haven't eaten in a while. You don't have a lot of calcium, which is a big problem. We need calcium for muscle contraction, for the nervous system. You need to make sure blood calcium is always at this certain set point. So if it's starting to dip a little bit, parathyroid hormone will be secreted and we will pull calcium out of areas. We'll make sure we're not letting any of it go in our kidneys. We'll make sure our intestines aren't letting any of it go in our kidneys. We'll make sure our intestines aren't letting any of it go and then we'll also go to our bones, potentially mine it out, stimulate those cells to help make sure that we're putting calcium in the bloodstream. So some of the viscera. 51:33 Another area here that we have we have the larynx we have to talk about. So if we were to peel off the thyroid gland, in this similar area we have the l? Larynx and the larynx is basically this whole box of a bunch of pieces of cartilage that get put together. So I think there's somewhere around like 16 different pieces of cartilage that articulate. Here. We won't get that detailed, but we should know thyroid cartilage, one of the main pieces. So on the anterior side here this is. This is a side view. Top left here we have the thyroid cartilage. That's what usually looks like a shield on your trachea, at the top of your trachea. Right at the midline of the thyroid cartilage, you have the laryngeal promise. That's the Adam's apple, so it gets more distended, with certain hormones being secreted in the area. 52:18 And then one of the other major pieces of cartilage we should be aware of. If we were to flip around the thyroid cartilage and look at the posterior side, which is what this picture is doing, we have this giant piece of cartilage that's going to swing down. That's the epiglottis. So the epiglottis swings down and specifically blocks off the trachea when we are eating, when we're drinking, just to make sure that we're preventing any of that fluid or food going down our trachea. So this is a lot of coordination here with moving some of the different pieces of cartilage. We have muscles that are going to be attaching that will move all of this apparatus. So one of the many reasons why swallowing is a complicated task yeah, so you're fluid. 53:02 Yeah, so then one other thing in the area of the larynx we need to address are the vocal cords or vocal folds. So glottis, whenever you see that term for glottis, glottis is a very general term referring to this whole area where we have the vocal apparatus. So, thinking on the posterior side, there where we saw the epiglottis, if we looked a little in here, this is where we would land. The two structures we need to know and we'll work on identifying this tomorrow on our bisective skull you can see these are the true vocal cords and then the false vocal cords, also called folds. What happens is we have the vocal cords which are going to be these flaps, here and then right above and I don't think this picture shows it very well right superior to the true vocal cords, we have the false ones. The false ones are a mucous membrane that help to cover the vocal cords the true ones and essentially they're there to protect the true vocal cords. I have a better picture. I think false are superior to true. 54:01 So this is a little video here that shows our vocal folds. So we got our true vocal folds, the white structures in this Right next door, this pink tissue. It looks like it's in the same plane, but it's actually a little superior. Those would be the false vocal folds and more of a mucous membrane, which is why they look differently there, and just for perspective. So each of these nodules is a little piece of cartilage. So as you speak, you're moving all of these pieces of cartilage to then move the vocal folds. 54:38 Alright, so moving on and actually at the bottom left there. That's a really good view, a better view than what we've been seeing. We've got the epiglottis at the top. Here we have what would be in this area, our vocal folds, cords, and we're seeing our trachea down here and this is our thyroid cartilage big red orangey color. All right, so moving to the trachea. So we've talked already about the pharynx, so naso oro laryngeal pharynx. 55:00 The anterior route here, once we get past the epiglottis or past that area, would be the trachea. So trachea is anterior to the esophagus. With your trachea, with your structures we need to know about. So hopefully only air is going down the trachea. It's going to lead to eventually our lungs, our bronchial system, to help provide structure to this area. 55:17 We have a lot of pieces of cartilage. The first piece of cartilage in your true area of your trachea is called your cricoid cartilage. So I'm going to write down here ring of cartilage. The cricoid cartilage is a full circle ring of cartilage, so it's helping to keep your trachea open. Once you get past the cricoid cartilage, what happens is you do not have full rings of cartilage, you have what are called C-rings of cartilage and they descend down the rest of the way of your trachea. Eventually, once you get to your bronchial system, that cartilage starts to change a little bit. But trachea, there are C-rings. On the back side, where we have the little gap in the cartilage, we have a muscle called the trachealis muscle. So it closes the C-ring so. So the trachealis muscle is going to help to change the diameter of the trachea just a little bit. It doesn't have a ton of control but let's say, if you're coughing, you're trying to get something up, that trachealis muscle can constrict and help to change the diameter. So these are the big pieces for us to be aware of with our trachea and again we'll see these with our bisected head tomorrow. You can see a cross-section of the cricoid versus the C-rings and you'll see a little bit of the thyroid part of it too. Could you repeat what the C-rings do? So they're helping to provide some structure to the trachea. 56:39 All right, so we have to talk about swallowing. We've seen now swallowing kind of be mentioned in a few different areas, cranial nerves, for instance. We've seen a lot of. We've been talking about high-weight muscles today. There's a lot of players involved with the process of swallowing. 56:48 So deglutition is the proper name for swallowing, and one way to kind of organize the events of swallowing is to break it up into three stages. So the first stage, or the oral phase, and this is describing when you have that food in your mouth, say, you are chomping away. So you have mastication muscles like your masseter working, your temporalis working and you're chewing up that food. You've got your salivary glands secreting saliva in also helping to break up that food and you're going to create what's called a bolus. A bolus is your chewed up food mixed up with mucus saliva. So essentially, now you've kind of physically broken it down, you You've done some mechanical digestion and now you have this ball, this bolus. So voluntary movement of the bolus to the back of the oropharynx is what's happening. 57:27 Stage two is going to be the pharyngeal phase. So now we're in the pharynx and now your soft palate is going to do a lot of the work. So you're making sure we block off the nasal cavity. Nothing's going upwards. We are now off the trachea with epiglottis and we are pushing it all the way in the back of the pharynx, that bolus. And then stage three. So now we're going to be starting to move down the esophagus. So esophagus goes here to the trachea. Here the esophagus has a lot of smooth muscle in it, so we're going to rhythmically contract that smooth muscle to push down the food, the bolus, and that rhythmic contraction is called peristalsis. A called peristalsis. A lot of structures involved Once we're not even quite getting into, for instance, what's mentioned here pharyngeal constrictor. 58:06 You have some sphincters involved in different areas. But we know that soft palate has musculature too. That's a big help here. The hyoid muscles supra and infra are all coordinated too. So I kind of put together a sheet here. This is essentially all things we have talked about, but in one place and just emphasizing the importance of swallowing and how complicated it is. So we've got trigeminal nerve helping out with some of the sensation to the area also moving some of our hyoid muscles. So specifically superhyoid gets innervated by trigeminal nerve. 58:33 Facial nerve, so we have the sense of taste coming from facial nerve. We've got motor innervation to some of the superhyoid muscles again the facial nerve, salivary glands. We have falacofrangel nerve intervening the tongue and intervening surrounding area of the soft palate. We have vagus nerve so we talked about vagus nerve at the top of the class there. So parotid sensitivities but also motor innervation to the area of the larynx and pharynx. We've got hypoglossal boon to the tongue and then one thing I just put on this list with that ansa cervicalis. So ansa cervicalis we mentioned as the nerve flexors coming from a few circular nerve roots, specifically innervates the muscles below the hyoid, infrahyoid muscles. Is salivation the same thing as the salivation? No, that would be a special sense. So I don't think I put sense of taste on these at all. Just for perspective, I'm just focused on swallowing, yeah, so my point here and toss this in the trash if you want to is just to help group some of these things and then again to emphasize swallowing and the importance of it. 59:35 So, especially individuals who have brain injuries, strokes, swallowing is going to be a big task to recover for some of those individuals. My father-in-law had a traumatic brain injury. He's a cranky, cradgy old man and was on a ladder by himself when going at home, fell off the ladder, shattered a bunch of facial bones and then had two subdural hematomas, one from hitting the front of his skull, his brain, and then it bounced back to the other side so hard he got two, so craniotomy the whole. Nine yards revision surgery was in neuro rehab for four months. So intense road. He was a zombie at one point, like not communicating, saying anything, barely moving, and he's totally fine now. It was pretty remarkable to see. But the struggle for him was getting his ability to swallow back. So he had to work with a certain therapist who could help him with this. You graduate with different foods, so it was going to be more difficult than soliditudes, for instance, but it's because all the nerves working, all the muscles, all the structures, all that coordination. 01:00:25 So this is an example of a swallow study. Essentially it's pretty much a moving x-ray type of fluoroscopy, and usually when they do a swallow study they give the individual different consistencies of food, like pudding and graham crackers, and see what's going on. So I think they walk you through the normal one first. So normal, everything's going down the esophagus, nothing's going anterior. So now you can start to see it float down the trachea. So that would be an abnormal swallow study and so you can have a lot of issues that develop because of that. If you are curious about swallow studies, there's a ton of them on YouTube. They're pretty interesting to watch, especially the ones that are really abnormal. You just see a whole pool of food go down and you can see the hyoid bone working in some of these swallow studies too, and the epiglottis, all right. 01:01:11 So last piece for us here we have to talk about the lymphatic system, always a piece to these sections here. Some of we've already seen. So, for instance, we've already started to talk about our superficial cervical lymph nodes, the congregations we have. We talked about, for instance, submental lymph nodes today. Our superficial cervical lymph nodes will always drain to the deep ones, and a lot of our deep ones are going to be right behind the sternocleidomastoid. So just a reminder about that. And then I've made a little flow chart for us here. So we are going to kind of revisit this topic often as we go through different regions of the body. Essentially, whenever we're talking about lymphatic drainage we're going to have the same end root. Here we're coming from the legs. Eventually we are emptying into the same place all the way, at the end of this list. 01:01:48 So to go through this, here we have the superficial cervical lymph nodes emptying into the deep ones. I'll use my pen. So then from there we have the deep cervical lymph nodes. We'll have these structures called efferent lymphatic vessels. All that means is those are tiny little vessels leaving the lymph nodes, going to the next place. Efferent means away, afferent means towards. So those little efferent lymphatic vessels are trying to converge and get to the jugular lymphatic trunk, which is a lot larger. Trunks are going to be larger than vessels. So then from the jugular lymphatic trunk we are going to have different courses on either side of the body. This is the variance on the right side and the left side. 01:02:34 If we are on the left side of the body, we are going to be emptying into something called the thoracic duct, into something called the thoracic duct. Okay, so thoracic duct, over there On the right side we're going to be emptying into something called the lymphatic duct. So less of a grand name. It is a much smaller structure. The thoracic duct actually collects from a lot larger of an area. We will talk much more about that when we get on into different areas of the body. You're right over here on the right side. 01:03:04 So what happens is thoracic duct versus lymphatic duct. No matter right or left, we're gonna be emptying into the same point in the venous system. So the venous system junction here is going to be at the junction of the internal jugular vein and the subclavian vein. What happens is that little it's not even quite correctly shown on this picture that little lymphatic duct on the right side is going to empty right into the ankle there. This is something. 01:03:27 If you're looking at a different app, a different text, it's going to tell you something different. There's four ways to describe this. The way that I want you to know is junction of the internal jugular vein and subclavian vein. So right where those two join up, we're going to be emptying at the ankle there. So some sources will say empties into subclavian vein Not fully correct, but that is the total path At this point. 01:03:48 Once we've emptied into that little angle there, we're now in the venous system. We're now flowing towards the heart here, to the superior vena cava. Now we just flow with blood, so that's how we get lymphed back into the circulatory system. So those are the lymphatics of the neck, for us right now the cervical lymph nodes, by far the most important piece, and we'll see the rest of this journey as we go on. All right, so what I'm asking for here? So when I go to create some review questions for our next class, our top class, are there certain topics that are elusive or tough to tackle? You're finding, you know, what would you like me to revisit?