Transcription
[Music] you might notice something a little different a little different uh I want to talk about the movements of the scapula. This is something that confuses students. It confuses me um and the scapula moves in more ways than most people realize. And there are three pairs of movements we should know about and a couple of pairs of movements most people don't know need to know about. I'm just going to talk about the movements of the scapula. The reason I've got this skeleton is cuz he's all stretchy so I can properly move the scapula. We'll talk about the movements of the scapula, how it moves. I'm not going to talk about the humerus. I'm not going to talk about the shoulder joint. I'm not going to talk about the rotator cuff. I might talk about the shoulder girdle a bit and talk about some of the muscles and how they move the scapula, but this is focused on the names of the movements of the scapula. All right.
[Music] Protraction, retraction, elevation, depression, lateral rotation or upward rotation, medial rotation or downward rotation. Those are the movements that we should know about. The other movements I'll come to you later. If you don't care about them, you don't have to watch the whole thing. Um, so the scap is really important because, well, it's it's a big part of how the upper limb is attached to the axial skeleton. It gives us our range of movement. It supports the upper limb um, but it, the scapula has got to move for us to move our upper limb throughout this wide range of movement. Right. Um, and if you've looked at the rotator cuff muscles, if you've looked at the muscles of the of the back of the chest or the muscles that move the scapula, you probably have a reasonable understanding of this. But let's make sure we're all using the same name so that we can communicate clearly. That's the bad news is that this isn't entirely standardized. So you might read different terms in different places, which is part of the confusion. But the basic three pairs of movements, we're pretty solid with. All right.
So remember that the scapula, it's got a bony joint up here with the clavicle and it's got a bony joint with the humerus um, but otherwise it's held against the thoracic wall, which is curved by lots of muscles as it moves around. Those muscles are keeping it against the thoracic wall and they're pulling it around um. Okay. So if I want to reach forward, so what I'm doing there is I am protracting my scapula. What's happening here is the scapula is getting pulled around the body wall anteriorly. Protraction. Serratus anterior is the big muscle around here that's largely responsible that for that protraction. Gets called the boxer's muscle because of the of the reach of the boxer. So protraction. So then the opposite of protraction is retraction, where we're bringing the scapula back towards the vertebrae. So protraction and retraction. The muscles in here responsible for retraction are the rhomboids, rhomboid major, rhomboid minor, and also the middle part of trapezius. Retraction. It's a good tick, I think that one.
Likewise, I think elevation and depression. So elevation, we're actually, so we're elevating the whole shoulder girdle. The scapula and the clavicle are elevating. So elevation of the scapula. And largely we have the upper fibers of trapezius responsible for that. Levator scapulae is a little muscle over here in the name levator scapulae, also helps with elevation. And then depression, we've got the lower fibers of trapezius and we've got pectoralis minor. And you might argue that the weight of the limb is also helping depression of the scapula. And you know, latissimus dorsi is running from the back to the humerus, so you might say those guys are also involved in depression. So elevation and depression. Most students are pretty good at elevation because we ask what what does the accessory nerve do? Old joke. But elevation and depression, easy so far.
Now the scapula rotates, but it can rotate on three different axes that are essentially none of those movements we've talked about so far. But we only really need to focus on one of those rotations and it's this. So this movement that is upward rotation of the scapula or lateral rotation of the scapula. And what we're looking at here is we're looking at the glenoid fossa. So the thing that's going up is this, the joint here, the the glenoid fossa of the glenohumeral joint. So upward rotation points the glenoid fossa upwards and that's also lateral rotation. Downward rotation is then either, you know, most largely bringing the glenoid fossa back to that position. Um, so medial rotation or downward rotation. Lateral rotation, medial rotation, upward rotation, downward rotation. Um, upward rotation, then the upper fibers of trapezius are pulling on the lateral end of the scapula and also serratus anterior is pulling on the tip down here to do to do that movement. And then to pull the scapula back again, we've got the rhomboids um and we've got levator scapulae pulling the scap back with downward rotation. So upward rotation, downward rotation. Uh, the purpose of this is that when the scapula is in place and you abduct your upper limb, you can only abduct so far. If you want to raise your arm above your head, you need to rotate the scapula like this. So upward rotation lets you raise your arm above your head. If you're doing overhead, overhead um dumbbell press or barbell press, this is why you're working upper trapezius is because you're rotating the scapula there. Right.
Those are the movements of the scapula that most people should know about, that that students of anatomy should know about. Those three sets of movements and those rotational movements, upward rotation, downward rotation, lateral rotation, medial rotation, same movement, two different sets of names. Don't call them anything else because they are two other ways in which the scapula will rotate. We'll talk about that now. But the other movements of the scapula are largely movements you don't really notice. They are a result of those other movements and the need for the scapula to move around the curve of the rib cage to stay close to the body wall. That's what happens normally. If there's a muscle weakness for some reason, maybe a nerve has been injured, then the scapula might come away from the body wall with some of these movements because the muscles that are supposed to be holding it against the rib cage are no longer able to do so. So it it moves outwards. So if you want to know the other movements, we have anterior tilting and posterior tilting, also called anterior tipping and posterior tipping. And what's happening here is that the the scapula is moving about this axis pretty much. So it's it's tipping like that. So that is anterior tilting and that is posterior tilting. And what's happening here is that with those other movements of the scapula and the scapula staying against the curve of the rib cage, for example, when you shrug your shoulders, if the if the scapular is going to stay against the rib cage, we have some anterior tilting and then as you bring the scapular back down again, you have some posterior tilting. But anterior tilting and posterior tilting. So we're thinking about the top of the, the top of the scapula, the top of the scapula is tilting anteriorly or it's tilting posteriorly. It's not a movement you really notice, but it's a movement that is described. It is a movement that happens alongside the other movements. Whenever we make a movement in the body, it's usually a lot more complicated than uh we like to try and believe.
And then we have external rotation and internal rotation. This is where it gets confusing. Right now, the scapula here is rotating about an axis kind of in this direction. So the scapula is is tilting like that. This is a movement that happens during protraction. So I said that when you protract the scapula, you bring the scapular around the rib cage anteriorly, but when you do that, the scapula to stay against the curve of the rib cage has also got to rotate that way. So that is internal rotation. External rotation. So the scapula is rotating about that axis. External rotation. This is, except this is particularly confusing because when we talk about a long bone like the humerus, we interchangeably can use lateral rotation and external rotation as the same thing, and medial rotation and internal rotation is the same thing. When we're talking about the humerus or the femur, you can't do that with the scapula. Um, lateral rotation and external rotation are different movements. It's confusing. I'm sorry, it's not my fault. I'm just trying to teach this. But um, those three first pairs of movements are those functional movements that we often talk about when we're talking about the muscles that move the scapula and the upper limb. Those you should know about. But just be careful. I think protraction and retraction, most people are good with. Elevation and depression, most people are good with. But that idea of lateral rotation and medial rotation or upward rotation and downward rotation, that's safe as well. Don't use any other terms for those things and you'll be fine. Um, and what, what you know, what we're trying to do here, we are trying to standardize this so it is a little bit clearer. But if you read um different sources, you might read slightly different things. And those other movements, they are, you know, movements we generally don't notice, don't generally talk about. But if you're going to be a physio or what have you, probably will talk about it. So that anterior tilting and posterior tilting and that external rotation and internal rotation really confused things. So if you don't need them, ignore them. It's okay if you ignore them until you become an expert on the shoulder and the scapula. Okay. I hope that was useful. That has uh certainly cleared things up for me, if nobody else. Um, right, see you next week.