 Hi, guys. We're here today to talk about the structures that we're going to study in lab. In lab, we're dealing with the superior limb and all the muscles, their attachments, their bony attachments, and their actions that they're responsible for in the upper limb. We're going to kind of organize the content by who's being moved. And there are between, you know, four and six muscles in each section that we're going to look at. I think there's a total of 24 muscles that we're going to know. And having all that information like attachments and actions to know for these muscles might seem a little overwhelming. The good news is most of the attachments you already have identified on the bones. So if you can create a visual in your brain for how the muscle, like where the muscle actually is, you can probably figure out the bone bump based on the bone bumps you already know because you're a rock star. All right. So I found this website and I am super stoked about this thing because it's online so it's free and it has some really nice, it's a nice summary. It's still, like, sorting through, like what's the most important thing is a little bit challenging. But let's start out with the muscles that move the pectoral girdle, which is basically the scapula. And so if a muscle moves the scapula, it's actually like we think of it as moving the shoulder. So we have four muscles that fall into this category and the first muscle in this group is pectoralis major. The nice thing about this site is that it'll show us an image of pectoralis major and we can actually dissect the group except pectoralis major went away. That was really lame because usually they leave pectoralis major, oh, that's because I'm in pectoralis minor land because the muscle that we're studying right now is pectoralis minor, not pectoralis major. That's pectoralis major, which is superficial to pectoralis minor. Okay, let's go study pectoralis minor because that's the one that actually moves the scapula. Now pectoralis major doesn't move the scapula. It's not in our group today, in this group. It's superior, whatever, we'll get there. Peck minor moves the shoulder. Okay, that should tell you right away that this is, we're going to have to have some kind of attachment to the scapula and in fact, if you look at this and it might be a little bit hard to tell, so I'm going to try to eliminate some of the other muscles so that you can see this more clearly. What are my attachments? I have an attachment to ribs. I also have an attachment to the scapula at the coracoid process. This is all super straightforward to you. The other cool thing about this site is that you can actually, there's an animation or whatever that will show you the action. If peck minor contracts, once you know where it is, then you're like, cool, ribs, coracoid process. Like, look, it's right there. I can totally see it. Once you've got that visual in your brain, then you can look at that thing and be like, okay, coracoid process to my ribs. What's going to happen if I shorten that? And you can actually figure out what the action is without even being told. The bottom line is that it brings the scapula forward and down, and so it's kind of a protract medial rotate of this scapula. A little bit hard to describe, and that's okay. If you can look at it and visualize what that is and then describe it, you'll be totally fine on an exam. Let's go ahead and fill this in for peck minor. What was one of my attachments? Let's go ahead and call it the coracoid process. And what was my other attachment? I vividly remember dissecting Myra and finding the peck minor and being like counting her ribs and remembering. I don't remember things like this very well, very often, but seeing that, oh my God, there's peck minor on ribs three through five, and I totally counted them, and it's stuck in my brain. That section is pretty amazing. So the action, like how are we going to describe that? It depresses shoulder, and keep in mind that I'm saying it depresses the shoulder, but let's talk scapula, because it's actually depressing the scapula, and it's kind of rolling it forward, rolling forward. How's that? I'm sure we can come up with some better words for that. Okay, the next one we want to look at is serratus anterior, so let's go take a look at that guy. Serratus anterior has serrated edges on the anterior portion of the muscle. If you see it right here, it's a deep muscle. It wraps all the way around. It attaches to ribs on the anterior surface, and it gives you this serrated look, and I say it's a deep muscle because it actually, now this is going to hurt your brain, it actually rolls around from the anterior surface about her. It rolls around to the posterior side of your body underneath the scapula, and it attaches to the medial border of the scapula. Now if that bursts your brain, I totally understand and can totally identify. Let's see if it will show us if we feel like, oh yeah, I can totally visualize that. Can you get rid of everything? Look, there, so can you see? Okay, imagine, here's the acromion process of my scapula, and the coracoid process of my scapula. So the scapula is on the back surface here, and you can see there's muscle tissue back there, and it literally slides underneath the scapula and attaches on the medial border, and that kind of hurts my head. Really? That's a strange thing. The serratus anterior is a muscle that keeps your scapula from flying off your back. When you do something like planks, holy crud. If you did not have serratus anterior when you were planking, you, your scapulas would like fly off your back and out into the universe, and that would be a bad thing. I don't recommend that. So next time you're planking, because that's always fun, go ahead and give a big woof-woof to your serratus anterior, because otherwise you wouldn't be able to do it. Let's summarize. Serratus anterior is attached to, since we, here's our scapula side, let's do medial border of scapula. Let's go with that. And then it also attaches to ribs, and I'm cool just calling it ribs. I mean, we've got numbers, but I can't remember what they are, like one through eight, something like that. And the major action that I care, I mean, there's lots of things that it does, but the thing that I want you to know is that it holds scapula, that says scapula, on back. So some of the actions that we're going to do, bicep sprake EI are super straightforward. You're like, oh, boom, that's awesome. Other actions, there's like a whole bunch of stuff going on. And if we go back and we look at serratus anterior, like, look at all those attachments, and look at all those fiber directions. You can imagine that the muscle fibers, because of the largeness of the muscle, there's lots of different directions for the fibers, which means we're going to have different actions facilitated by one muscle. And that's where it can get a little overwhelming. How about trapezius? Trapezius is the next one. Trapezius is a muscle that makes up the shoulder curve here. It attaches all the way down your spine, it attaches to the lumbar vertebra, look, to T12. So it goes all the way down your vertebra. It attaches to your skull, and then it jogs on over and it attaches to the scapula. It attaches to the acromion and the spine of the scapula. Now, remember that the acromion on the scapula was attached to the spine? The spine kind of terminated laterally in the acromion. You can palpate your acromion process. And that whole line, it's kind of fun to palpate yourself and be like, oh, that's, I'm massaging trapezius right now, but of course I am. Anyone's welcome to, never mind. All right. Now, the action of trapezius. Here, like take a deep breath. This is an example of a muscle that actually has three main parts, and they have three different names, and they have three different actions because of the fiber directions. Okay, we're cool with that. Let's go ahead and watch the actions. Okay, the upper fibers totally make sense. The upper fibers are going to elevate your scapula, and it looks like we have this upwardly rotate, whatever. That's awesome. But can you visualize that? Let's watch it again. We're elevating, those guys are shortening. Now, take a guess. What's going to happen with my middle fibers? Look at that. They shorten, and they're going to adduct or retract the scapulas. It does both of them, and so you do kind of this like attention action with those middle fibers of the trapezius. And then the lower fibers, what are you going to expect? You're going to expect a depression of the scapula, and let's watch that one, too. Isn't that interesting? So this single muscle depresses the scapula and, I want to say, elevates it. It expresses? No, not that. Okay, so let's go put a list. Let's go put a list on this thing. Attachment number one. I can never remember which one it is. We're going to the, so let's do spine of scapula to acromion. Does that work for you? And then let's do skull and ribs. Like, we're attaching all the way down. Like, and we've even got some ligaments in there that we'll call those attaching. And you know what? Here's what I'm going to say about the action. Let's just do varies. And that's because you can visualize. We're going to elevate, we're going to adduct, and we're going to depress. Depending on which fibers we're talking about. And it's, you look at the fibers and you can figure out the action just by looking at the fibers. You don't really have to memorize actions. In fact, I don't really recommend it. The last group that we're going to look at that moves the scapula are the rhomboids. Now, the rhomboids are plural because there's rhomboid major and rhomboid minor. Rhomboid minor is superior to rhomboid major, which is inferior to whatever. The bottom line is we're going to consider the rhomboids all together. If you look, in fact, I don't think, let's see if rhomboid major is next. Look, I mean minor. Minor is here and I'm just going to, oh, look, this is good. Let's do it like this, except I want to go back and do it on the one that I said I was going to do. Look, there's rhomboid major. There's rhomboid minor superior to it. Rhomboid minor and they're basically just, they're like the same muscle almost and they just have two different names. So rhomboids is cool. You tell me, just looking at it, where are we attached? Medial border of the scapula and the vertebrae. And look, it looks like T2 to T5 is rhomboid major, so it looks like T1 and maybe C7 are rhomboid minor. I'm not so worried about that. You should be able to identify it and if life got real tough, you could probably figure it out. And what's their action going to be? It's going to be another like draw to attention dog pound. There they go. Nice, I like this one best. Tracked or adduct the scapula, bring it closer to the midline and that is the action of the rhomboid. Okay, those guys moved our scapula. How did they move the scapula? They had an attachment to the scapula. If you don't attach to the scapula, you're not going to move it. And that was four muscles and you're done with four muscles now. Now we're going to move the arm. What is the arm? The bone that we would expect to attach to if we're going to move the arm. Go ahead and think on that one. Hopefully that is not hard.