 I didn't finish filling out my thing. Did it bother you? Of course it did. I'm sorry that I caused you any kind of a stress response. That was not the intention. Ron Boyds, who we attach into doggies? Remember this, we were on, ooh, I'm going to do it in the same color. Look, medial border of the scapula, nice. And where was my other attachment? My other attachment was this one that I mis-wrote. I'm almost perfect, you guys. Medial border of the scapula to the vertebrae. And where did I make mistake? Trapezius. Trapezius isn't attaching to ribs. Trapezius is attaching to vertebrae. My question is, did I say ribs? Or did I say vertebrae and write ribs? Were you freaking out when I did it? I'm very sorry for that. All right, let's talk about the arm movers. Do you think this is it? Are there only four muscles that move your humerus? Nope, there's more than that. But all four of these that we will learn have an attachment to the humerus. The interesting thing is that most of our muscles that are attaching to the humerus are attaching at the greater or lesser tubercle of the humerus. Just kind of handy. Like that, oh, I can remember that. I can remember my tubercles. And then sort them into a couple of groups based on which tubercle we're talking about. Let's start out with pec major. I tried to start out with pec major last time. I was super excited to do pec major, but now it's time. Pec major is the giant one. Palpate your pec majors. Nice. And you know pec major is going to attach where? Where would you expect? It actually attaches to the sternum. And let's get rid of some of this extra stuff so that we can just see pec major. Nice. And what do you notice about pec major? Look, two names, one muscle. It has two pieces, just like trapezius had three pieces, but thankfully it's just one muscle. So that's cool with us. Notice that we attach not just to the sternum, but we also attach to the clavicle. So here's the medial attachment is kind of broad, sternum and clavicle. And then, like I said, we're moving the humerus. So of course we have to span the shoulder joint and attach to the humerus. And where are we attaching to the humerus? If you look at this, right on the tip of my, whatever that thing is, pointer, it's the greater tubercle. Remember, the greater tubercle is lateral to the inner tuberculular groove on the humerus, which is on the anterior side. You've got this, you bone lab, you're like bone experts. Here's the lesser tubercle right here. So you can even just look at this and be like, okay, it's actually a little bit inferior to the greater tubercle. And you can go like, look, thanks a lot, pals. Look at all the attachments that we can do here. Sure, do you want to do a, no, just call it greater tubercle and we'll be cool. And then let's take a look at the action or think about the action. What's going to happen if we're attaching to the humerus at the greater tubercle and we're attaching to the sternum? What's the action when that muscle shortens? We're going to immediately rotate the humerus. Does that work for you? And if you're out here, then we're going to adduct the humerus as well. So let's go ahead and make that written. I will not forget it again. Attachment number one, let's go ahead and attach to the greater tubercle. And my greater tubercle is going to be, I wonder what color I used everywhere else, greater tubercle of the humerus. Probably on an exam, you should say greater tubercle of the humerus. Don't just say greater tubercle. And then my other attachment is clavicle and sternum. And my major movements are medial rotation and adduction. Bring in that humerus right on in. Bring it in. Latissimus dorsi. Latissimus dorsi is a posterior muscle. Let's see what's going on with that guy. I can do that. Latissimus, look, vertebrae. Here is latissimus dorsi. All right. Where is it attaching? I believe it's T6 down. And this is actually called an aponeurosis, which means it's a giant tendon sheath. And so the latissimus dorsi is like sandwiched and covered and aponeurosis-sized with that tendon giant thing. And you can see that really well in our cadavers. So it attaches here, and then it also, oh, look, T7, I mean, it's close to T6. And then, yeah, yeah, yeah. To the inner tubercular groove, I wonder if I said that for latissimus. I said lesser tubercle, which means it's a little bit more medial. So let's take a look at that. Let's jot down our notes here. Latissimus dorsi is going to attach to the vertebrae. I'm not going to put it in that column. I'm going to put it in this column. Vertebrae, and then I have it as lesser tubercle. And both of these are kind of inferior. So it kind of gives you a direction, an orientation in comparison to the inner tubercular groove. So if you're on the greater tubercle side somewhere in that span, then you're going to be slightly lateral. If you're on the lesser tubercle side, you're going to be slightly medial. And you can imagine that the, what's this called? Look at this dorsi. Oh, geez. Look at how it flies underneath the muscle, underneath the bone and attaches in this location. It could go around the backside, but it goes anterior to attach to the lesser tubercle. And tell me what's going to happen when it contracts. You are actually going to get possibly a little bit of medial rotation. Biggest action of this guy is adduction. Adduction, can you see that? I didn't mean that, so it's biggest action. Its biggest action is extension of the humerus. So let's go write that down. We have extension, we have adduction, and we have a tiny bit of medial rotation. The lats are called swimmers' muscles because, oh, this is going to hurt my head to even try to pretend like I'm visualizing, but think about the butterfly stroke and how your hands go up, you butterflyed. And then you do this massive extension of your humerus to pull all the water and swim forward. That extension is latissimus. You can grab latissimus. You can grab the posterior portion of your armpit, palpate your latissimus dorsi. There's another guy in there. Oh, then the other guy that makes up the posterior portion of your armpit is Tiri's major. What do you know? Let's go check out Tiri's major. Tiri's major, there's two Tiri's-izzes, and you're going to know both of them. Tiri's major is the inferior Tiri's. This is kind of an interesting thing. Take a look at this. This is triceps. Triceps brachii is the posterior muscle on your arm, and it actually is responsible for forearm extension. So we'll talk about it in another group. But the long head of triceps brachii attaches to the scapula between Tiri's major and Tiri's minor. So you can see Tiri's minor right here. It's a big one, and it's inferior. And here's Tiri's major. It's a little one, and it's superior. And the long head of triceps brachii travels between them to attach to the scapula, which I think is kind of cool. Tiri's major, like I said, also makes up part of your armpit, and we're attaching to the medial border and the inferior, medial inferior border of the scapula, and it attaches to, I think, the greater tubercle. Come on, Tiri's major. I mean, the lesser tubercle, because that's exactly what I just said. Look, I could have just looked here. The medial lip of the inner tubercular groove means medial is going to be lesser tubercle side. Totally cool. Let's write lesser tubercle, though, so that we can visualize that. And then look at our actions that we've got going on, because I'm just checking here. I wonder if it's true that medial rotation is always lesser tubercle action. Are there any lateral tubercle attachments that could laterally rotate? I can think of how it could happen, so ignore what I just said. It also extends the arm just like lats. In fact, I read somewhere that the Tiri's major has the exact same actions as the Tissimus dorsi, and in fact, they sometimes call it the lat's little helper, the Tiri's major, that is. Tiri's minor, we're not going to talk about yet, but we're going to do that in another group. Okay, so let's see what we can remember. Tiri's major attached to the inferior and medial border of scapula. So let's do inferior and medial scapula, and then it also attaches to the lesser tubercle, and we'll do that in purple again. Lesser tubercle, and then doggies. I'm going to say it does that. It does the same stuff that latissimus dorsi does. Deltoids, deltoids. Deltoids are one of the muscles that you're like, man, these things are cool. It's big, it forms this lovely shoulder, like the piece of shoulder that you're like, you whack somebody on their deltoid, and it's a meaty spot, it can totally take a whack. It can wax it, well, don't, I didn't say that. We should be friends, not whacking each other. Okay, forms the groove or the curve of your shoulder. Deltoid also comes in different parts. You have an anterior part of deltoid, and you have a middle part and you have a posterior part, and just think about this for a second. The anterior part of deltoid is going to cause flexion of your arm. The posterior part of deltoid is going to cause extension, and then the lateral, the middle piece of deltoid, is going to cause ABduction. Seriously? Like it antagonizes itself. One muscle has all those different actions, and if all you have to do is relax, you're going to have to get crazy, all you have to do is look at its attachments and look at the muscle fiber direction, and then you can totally figure it out. You can figure out that kind of stuff. So don't freak out. Whatever you do, we're in anatomy, and you're doing this and we're not going to freak out. So where are we attached? This is the best attachment of them all. Deltoid, what? Tuberosity. There's actually no reason for me to write down what I say, because it's not like anyone can read my writing anyway. Attachment number two, all of them converge on the deltoid tuberosity. Attachment number two is like this whole ring of scapula and clavicle, like spine and clavicle, scapular spine and clavicle. Let's just go check, and then our movements, let's do that really fast, ABduction, extension, and flexion. This is crazy, this is crazy talk. What was I coming over here to look at? I have no idea what I was coming over here to look at. Nobody knows. Okay, those are my arm movers. Let's talk about the rotator cuff. The rotator cuff muscles also attach to the humerus, and you already know why, because we've talked about the shoulder joint. Okay, be right back.