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Muscles of the Scapula: Video #7 of Introduction to Functional Anatomy

Muscles of the Scapula: Video #7 of the Introduction to Functional Anatomy series explores the key muscles of the scapula, the shoulder blade. In this video, viewers will learn about the prime mover muscles of the scapula, their origins and insertions, and the function of each muscle. As the scapula is a primary participant in shoulder and arm movements and muscle communication, this video offers viewers the opportunity to further their understanding of the intricate anatomy and

Transcript

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Alright so let's get into the muscles
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now, and I want you guys to try to think
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through this process. I know the answers are on the board, I'm not taking them
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away from you, but let's try to think through this. So the first muscle up
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there is your serratus anterior, yeah, your serratus anterior if i remember
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correctly
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inserts into the vertebral or medial border of your scapula, which is which
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side? Which side of my scapula is my vertebral or medial border? Touch it,
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palpate it, this side right the inside. Now it courses underneath my scapula
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wraps around and it originates on the top eight ribs, you guys cool with that.
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You guys know this muscle, you guys ever seen bodybuilders and they do this thing,
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they're like dude I'm so huge my lats got teeth. You guys know what I'm talking
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about. No you have no idea. You guys know what I'm talking about those little
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little teeth that come out right here, that's not your lat that's your serratus
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anterior poking out, in fact the name serratus comes from what, it looks like a
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serrated knife right, it's that shape. Well if it attaches from ribs to scapula
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what joint is it going to move, not my shoulder, my scapula right. We kind of
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said that these two joints, we say we can kind of combine them, and we call it
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movement of the scapulae right. So we're talking about the scapula. So that's the
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joint, what are my joint actions for my scapula, let's make a little word bank.
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Good.
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Protraction, retraction, who are we missing? Good.
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So we know that the serratus anterior is going to move my scapula, and these are
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my scapular joint actions. Now we just have to figure out which joint actions
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my serratus anterior is going to cause. Well is my serratus anterior
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going to move my ribs? Probably not much. Ribs don't like to move all that much.
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It's definitely going to pull my scapula then towards my origin, which is going to
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look like what? What is this muscle going to do when it contracts? Right so is it
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going to do this? Show me, if you can't tell me show me. So what joint action is
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that? Protraction, right protraction. Now the other joint action the serratus
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anterior does is a little complicated too, well it's not complicated it's just
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not as easy to visualize. So what ends up happening is, if, what would happen to my
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scapula if my seratus anterior pulled the bottom of my scapula in this
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direction? What joint action would I have?
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Upward rotation.
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That's it, we're done with serratus anterior. Was that terrible? Yep that was
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terrible, okay on to the next muscle. Should we do PEC minor, sure why not, why
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not do the PEC minor. So my PEC minor
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originates from ribs three four and five, and inserts into my coracoid process. So
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it's a muscle on the front here right. So
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draw the front of my scapula, my little coracoid process here. Put some ribs in
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little PEC minor.
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You guys want to feel your PEC minor. I'm going to show you how to palpate your
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PEC minor, which direction are those fibers? More or less vertical right. Which
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way does your PEC major run across? So your PEC major is on top of your PEC
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minor, so we need to feel through your PEC major. So what you're going to do is
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you're going to kind of relax your PEC major. On the outside of your PEC major
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here you're going to strum this way, and what you'll start to feel if you kind of
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dig in there, is you'll start to feel like some vertical guitar strings that
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you can kind of strum over, that are probably pretty tender. Some
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of you guys a little tender? These guys tend to get pretty tight, yeah, no. Is
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anybody having a problem feeling their PEC minor? I can come over and help you
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palpate. I don't have a problem with this. Who can't feel their PEC
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minor, everybody's going to feel their PEC minor. Alright so your PEC minor is right,
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right and those fibers right there. So you guys are probably just not pressing
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hard enough, or your pressing too far over, those guys right there, those guys
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right there. Everybody everybody I touch just like oh god yes these muscles have a
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tendency to get tight, sore. Everybody got it, you got it? Press deep, it's right here.
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Alright so what do these fibers do? What do these this muscle do? What joint
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actions? Well what joint does it cross?
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What joint? Not shoulder joint, shoulder would be the combination of my humerus
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and my scapula, this goes from ribcage to scapula, which means who is it going to
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remove? Scapula alright. So what joint actions do you think this muscle can do?
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Protraction it's on the front, that's a good guess.
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What else? Depression right, yeah it has that vertical arrangement, it's going to
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want to kind of pull this way, right. If it pulls on the outside corner that way,
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what happens? And a little downward rotation, nice job. That's PEC minor. Yes
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ma'am great question. So traditionally origins and insertions have been based
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on, origin is the more stable of the two attachments of the muscle, but that
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doesn't always work out. You will see some textbooks where it's written
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proximal and distal attachment right. Generally origins are more proximal,
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that's not always the case. Let me tell you how much I care about which one's
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the origin and which ones the insertion.
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Initially guys you don't even have to memorize the origins and insertions. If
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you can memorize the bones and visualize roughly where they're at on the bone,
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you're in good shape. Later origins and insertions will mean a lot more to you
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as you get more into like pathology and problems that happen, and injuries that
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happen, then you have to start understanding origins and insertions a
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little bit better right. Now your big thing today, what bone does it attach to?
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What joint does It move? What direction is it going to move that joint in? That's
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it right, slowly but surely. You can add origins and insertions later, and
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honestly whether you flip them it doesn't matter. I mix up origins and
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insertions all the time. As far as which ones which, guess how much it affects my
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practice, oh my god did you see what he did he touched the insertion and he
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thought it was the origin, haven't been fired yet for that one. You're okay, all
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right. Trapezius, you guys know where your traps
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are? Do you know why your trapezius is called your trapezius? It's shaped like a
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trapezoid. What's the trapezoid shape,
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it's a kite shape right. You guys know that? So you guys are doing good in
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kinesiology and you did great in geometry, is what you're telling me, um. So
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yeah trapezoid is a kite shaped, and that's how your traps are shaped. That's
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a trapezoid, there's a lopsided trapezoid, let's change this chest a little bit.
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Everybody's cool with that all right let's, the funny thing about the trap is
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it's actually kind of like three muscles.
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Too big, that's not going to work all right. Head, spine everybody's good with that?
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Scapula.
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...blank
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All right now let's draw the trap. So we have upper trap that goes from the
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acromion process and spine of the scapula to external occipital
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protuberance. down your ligamentus nuchi, which is looking at in your spine,
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and into maybe the top thoracic vertebrae. Then you have more middle
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trapezius, it connects to kind of this midsection of the spine in your scapula,
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and then some more of those middle thoracic vertebrae. You guys still cool?
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Maybe this one actually comes off more like this, and then you have your lower
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trapezius which goes from spine of scapula all the way down to t12. So you
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got upper, middle and lower.
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So the trapezius goes from spine to scapula. What's it going to move? Your
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scapula for the most part. All right now let's start with the upper, that's that's
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this fiber direction right here. What joint actions do you think the upper
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trap is going to cause? Maybe some elevation, you guys think that's a good
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that's a good call, that's a good call. So we got a little bit elevation, what else?
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Yeah pulls on this outside edge here right, so if it pulls up on the outside
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edge isn't my scapula going to want to do that? Yeah so it'll contribute to some
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upward rotation. What is the middle one's going to do? These guys. Which one? A
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muscle can't do two opposing joint actions. Yeah if it contracts it's
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going to retract.
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What about my lower traps, what are they going to do? Depression, that's good call.
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I think they'll pull this way.
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What else, and that picture started out looking so clean and now it's beginning
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to look like a mess, sorry about that. Start over.
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Just do one scapular again,
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and the purple marker is dying all right. So I had my upper guys pulling this way,
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i have my middles pulling this wa,y and my lowers pull in this way. So my lower
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will do depression, what else will it do?
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Whew we have, we have a debate going? I heard one upward rotation and one
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downward rotation, which one is it going to do mmm. You guys remember my pinwheel
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analogy? You guys want to change your answer, can you guys see this, if I pull
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down on this inside corner what happens to my glenoid fossa, it goes up right. Did
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you guys see that if I pull down here, this goes up. Upper trap pulls from the
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outside, which is why it also goes up.
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Does that make sense? Cool you guys are cruising through the scapulae muscles,
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cruising. Levator scapulae with a name like levator scapula, what do you think
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is a joint action this muscle might contribute to? Elevation, thank you thank
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you. Sometimes we get to give me in the PT or in the anatomy world, you got to take
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them when they come alright. So let's do levator scapulae.
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Levator scapula, what joint are we moving again? Yeah i'm going to guess with
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levator scapulae is the name, we're also going to be moving the scapula. Given
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that it has an origin on the superior angle of the scapula, and then an
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insertion into the transverse processes of C1 through 4. Alright so up on
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the top of the cervical spine, it kind of looks like this. What joint actions do we
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got? Elevation, but you're not done. So i agree with you its elevation, it will
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definitely do some of this. but if it pulls on this corner what happens to
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this? Yeah it's a downward rotator. So by pulling up on this corne,r that causes
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this guy to go down that way. So it makes sense? Cool.
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You guys ready for rhomboids.
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Rhomboids there's a major and a minor, but for we can think about them as one
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muscle for the most part. They go from C7 to T5 alright, C7 to T5 on the spine to
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the medial border of the scapula. Why are they why are they called rhomboids,
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because they're shaped like a rhombus.
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Alright if they go from spine to scapula what are they probably going to
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move? Scapula, based on the direction of their fibers what joint action is it going
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to be good at? I like that, what joint action is that? Retraction. So you have a
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muscle its shape like this, yeah it's going to pull this way, anybody want to
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take a guess on what rotation it does?
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Everybody's cooled down word, but you guys got that pretty quick huh. So yeah
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you can kind of see how in this direction it would pull a scapula here
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right, or another way to look at it is if I upwardly rotated my scapula what would
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happen to my rhomboids? They get stretched out right, which means when
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they contract they pull me back down into downward rotation. Does that make
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sense? Alright you guys are killing it, killing it. So I think we're ready for
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our first graph, go to page 11. So I'm going to make you kind of flip stuff, all
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the answers you need we've already gone over, but I'm just kind of flipping how
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you look at this. So what I want you to do is how many boxes do you guys got? One
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two three four five six seven eight so they can, in that graph I
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included anterior and posterior tipping as the last two boxes, you can skip those
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if you want. I want one joint action per box for the six joint actions we have up
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here. You're then going to tell me what plane each one of those joint actions is,
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what muscles are responsible for each joint action, and a sample exercise for
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each joint action, you guys good with this? I'll give you a big hint on the
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muscles, there's at least two muscles per joint action. In fact for most of the
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joint actions there's only two muscles. There is a couple where a third muscle
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could be added. You guys got, how much time you need, five minutes. You guys can
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confer with each other, and then we'll throw it up on the board.
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Alright so what are my joint actions guys?
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So I got protraction, retraction, what else? Upward rotation, downward rotation,
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elevation and depression. What plane is protraction in? Transverse. What plane is
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retraction in then? Transverse. Upward and downward rotation? Frontal.
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What about elevation and depression? Frontal.
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Alright we already knew that from earlier today. So now let's add the the
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muscles to this. Who will protract the scapula? Serratus anterior is actually
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your primary protractor so you guys can put a star by that one. Who else?
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Pectoralis minor.
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Who wants to pick an exercise, what's an exercise that includes protraction? Maybe
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not pull ups. Bench, bench, anything anything, we in fact we could generalize
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a little bit and just call it pushing. Anytime you push something you want to
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protract your scapula. What about retraction ,what are the muscles that
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retracts? Middle trapezius and rhomboids.
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What's an exercise that would include retraction? Reverse fly sure. If
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pushing includes protraction, what probably includes retraction? Pulling.
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Upward rotators? Serratus anterior, thank you big important one. This is one of the
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ones that has three muscles, upper and lower traps.
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What's an example of an exercise with upward rotation? Lateral raise sure.
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Downward rotation? Pectoralis minor
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and levator scapula and rhomboids, nice job. What's an exercise? Pull up sure.
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Elevation, who's going to elevate? Upper trap and levator scapulae.
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Exercise? Shrugs.
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Depressors? PEC minor and lower trap.
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Exercise, that one's a tough one right, we don't really do a lot of exercises with
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just depression. No dip would pull you into depression. maybe the top of a dip
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right like if you really try to push through the top, I could see that top of
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a dip. There's a physical therapy thing,
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something called a functional pushup.
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I'll show you guys what this is so people for example who have lost some of
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their lower extremity function right, they don't, they're not able to use their
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legs real well, and you got to teach them how to get around to bed, and if you can
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get them sitting how could I have them scoot side to side on a bed with limited
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lower body function?
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Right so that's scapular depression right and then they shift over. Cool
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little movement pattern. Alright so you guys could write that down as an example.
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How'd you guys do on that graph? At the very least you have a nice little
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study guide for the scapular muscles right, and that's all the scapular
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muscles, that's it from us, you guys nailed it.