Name: Pectoralis Major, Latissimus Dorsi and Teres Major: Video #10 of Introduction to Functional Anatomy
Uploaded: 2023-04-26T01:00:15.000Z
Duration: 19 min 2 s
Description: Learn the functional anatomy of the pectoralis major, latissimus dorsi, and teres major in this educational video from the Brookbush Institute. Learn about the joints they cross, the joint actions they will perform, and how they work with other muscles at the shoulder. Great for students looking to deepen their knowledge of functional anatomy.

English captions

https://stream.mux.com/HDJ5t7w00ncWEmLG6Wba01dzXJb6kv1OnAkeJd8hjmn9Q.m3u8

Learn the functional anatomy of the pectoralis major, latissimus dorsi, and teres major in this educational video from the Brookbush Institute. Learn about the joints they cross, the joint actions they will perform, and how they work with other muscles at the shoulder. Great for students looking to deepen their knowledge of functional anatomy.

Understanding the Pectoralis Muscles

Joint Actions and Pectoral Contributions

Introducing the Latissimus Dorsi

Analyzing Push-Pull Dynamics in Training

Teres Major and Internal vs External Rotation

Unpacking Shoulder Muscle Functions and Posture

Pectoralis Major, Latissimus Dorsi and Teres Major: Video #10 of Introduction to Functional Anatomy

Pectoralis major, how major, what does major mean? Here's the weird thing about pectoralis major there's a pectoralis minor right, we already went over it. Pectoralis major crosses what joint? Pectoralis major crosses the shoulder, what does the pectoralis minor cross? Scapula, they're not even related, I don't know how that works, but we got pectoralis major crosses the shoulder so do we have the right word bank up? Yeah we got the right word bank up right that's the shoulder word bank. Flexion, extension, abduction, adduction. Can my pectoralis major do upward rotation? No, that's a scapular joint action. So we have this pec that goes from sternum and clavicle, we're going to draw the glenoid fossa here to the humerus, everybody with my diagram. I try to get fancier but we know what happens when I get fancier, it just looks messy. So my pec goes kind of like this, we have some fibers that come in from the clavicle, and then some fibers that come in from the sternum, kind of looks like a pec right. Most of those fibers run in what direction? Horizontal. Okay so let's start what are our horizontal plane joint actions? Horizontal abduction, adduction. So those are our horizontal joint actions, what do you think the pec will do of those joint actions? Horizontal AD or horizontal AB? AD-duction yeah, your pec is your primary horizontal adductor. Alright so it attaches to the front of my arm here, what do you think it's going to do as far as rotation? Internal rotation, cool. Alright then we get a little tricky, we have a clavicular head and a sternal head. So this clavicular head it runs like this, what muscle does it kind of run parallel to? Anterior delt right, what does my anterior delt like to do? Flexion, do you think these portion of my pec could at least assist a little bit in flexion? Everybody do that, like help out, sorry did not mean to be quite that sarcastic, can you guys feel that contracting a little bit? So if you do shoulder flexion the clavicular head of your pec can help out a little bit. Sternal head, now we got some fibers that run this way right, they kind of have more of like a downward angle, what other joint action do you think they could help contribute to? A little bit of adduction yeah, sure I mean directly it would be diagonally but that's a little adduction right. How many you guys have done cable crossovers for your lower pecs? There's no such thing as lower pecs but you do have a sternal head of your pec right, so yeah a little bit of adduction. You guys know who Hulk Hogan is? Yes right Hulk Hogan used to do what when he got into the ring? I think we found a Hulk Hogan fan all right, yeah but he used to show off his pecs right, he used to do that whole arghh. Well if you're going to show off your pecs can you do horizontal adduction? No because your mammoth 19 inch pythons get in the way, right you want people to see them so how do you contract your pecs? With a little bit of adduction, you guys got how that works. Probably not a rate great way to show off the clavicular head right, but a good way to show off the sternal head that make sense. So next muscle, you guys destroyed the pec, oh exercise graph, let's do chest fly. What joints are moving? Glenohumeral joint, are we stay in fancy with this. Glenohumeral and, yeah it would be SC and AC joints, would be the shoulder girdle, those are the joints that are moving, aka the scapula thoracic joints, scapula thoracic. We've just been calling it the scapula for ease. All right joint actions, so this is horizontal adduction we're adding to the midline in the horizontal plane. What's going on at my scapula? Protraction good. Muscle cause, muscles that do horizontal adduction, pec well, pec major will do horizontal adduction both heads. Who else? Anterior delts, how many of you guys have been a little short sore on your shoulders after a bunch of chest work? A little bit yeah yeah. Protraction, who does protraction? Serratus anterior and pec minor cool, a lot going on in a chest fly. This is not internal rotation, what's internal rotation? Yeah this is internal rotation, so unless you do this with the weights, don't do that with the weights it's not going to help anything, it's not internal rotation, does that make sense? All right I think latissimus dorsi is up next. Latissimus dorsi which roughly translates to widest back, this is the biggest muscle on your upper body and it is a big muscle. You see it's it's origin is all of this right, it goes all the way from like posterior, iliac spine part of your pelvis, all the way up to T7, so mid thoracic spine, a lot of attachment area. And then all of that thoracolumbar fascia in between, and then its insertion is the intertubercular groove of the humerus, which is the groove between the two bumps on the humeral head, good call. Alright so this is a big muscle on the back, goes from here wraps around the ribcage, inserts into the front of the humerus, all right so what is it going to do to the to the arm, what is going to do the shoulder? When this muscle contracts, adduct, how'd you come up with adduct? Well contract contract right, so if it shortens this way, right from up here, is that going to pull my arm down in adduction? Yes in fact that exercise is known as a lat pull down. What else is it going to do? What if I start with my moves, but what if I start with my arms up here? Will it pull me down, sure so what joint action is that? Extension. Alright this is a muscle that goes from the back to the front of my humorous right. Internal rotation or external rotation? Ooo... divided. Alright so this muscle wraps around here and then attaches in like this. How many of you guys say internal rotation? How many of you guys say external rotation? All right do you mind standing up being my model real quick? So if I'm her latissimus dorsi, and I reach around like this and grab the inside of her arm right, stop moving,  all right I grab the inside of her arm like this and I shorten, which way am I going to rotate her? Yeah internal rotation, weird huh, this muscle on the back comes like this and pulls down this way right, see how that works, so internal rotation thank you. Let me show you why knowing your functional anatomy is important, how many of you guys do push-pull days in the gym, little old school but a lot of guys will still do chest and back together because I think they're opposites and all that fun stuff. What do they work, so their lats is what they're doing on their back right, and then pecs are on the front, are these muscles truly opposite? What does my pec do again? Horizontal adduction, adduction, internal rotation and adduction right. These muscles opposites? Not really, so then we wonder why certain individuals who don't do enough of balance work, and don't do enough flexibility work and enough to correct some of the dysfunction they create, walk around like this right we talked about Captain Protraction, aka ILS right, if all you're doing is pecs, pecs, pecs, pecs and then all your back work is lats, lats, wouldn't it make sense that eventually you'd start getting a little internally rotated at the shoulder joint? Something to think about. Teres major, teres major goes from lateral border of my scapula wraps around into the front of my humerus, very similar fiber direction to who? My lat, so guess what my teres major does? All of the same joint actions right, this is your lats little brother. Any of you guys have younger siblings who wanted to do everything you did, the only thing the teres major won't do is what the lat does at the lumbar spine which we'll talk later about with core, that make sense. Now so teres major does internal rotation, adduction, extension, we said there was a teres minor, what does the teres minor do? External rotation because it's part of what? The rotator cuff and we know that it externally rotates. You guys see how that works? So I gave you that little teaching cue of remember teres minor helps out lesser smaller muscles being the rotator cuffs. I think of the teres major is helping out a major muscle, the largest muscle on my upper body, and that's how I keep the internal rotation of teres major straight and the external rotation of teres minor straight, does that help you guys a little bit? Good make a note somewhere, highlight, and then do this graph. Internal and external rotators of the upper body, remember when I said put a star by certain graphs, this is one of them. Internal and external rotators of the shoulder, this covers a lot of your shoulder muscles, give you a good idea on how this stuff works. Internal rotators of the shoulder, subscapularis nice, anterior deltoid try try to keep these in order of size here, I'm missing some big ones, pectoralis major, if teres major does it who else does it? Lats right, teres major and who mmm IT what, it externally rotates right so infraspinatus and who else? That graph does not look balanced to me right if we just match these up for size let's say the teres minor and teres major are roughly the same size, infraspinatus and subscapularis roughly the same size, posterior and anterior delt roughly the same size, is there any external rotator as big as the lats as big as pec major so the two largest muscles on your upper body are both internal rotators, does it make sense why we've never seen the postural dysfunction shoulders externally rotated? Never actually seen that postural dysfunction. I'd be I think it'd be excited if I did see it, like wow I didn't even know if that could happen. Yeah it doesn't help that posteriorly we want to be here, we talked about some of our gym activity might be a little biased towards this internal rotation thing, and now we're learning that there's a third reason, maybe a structural fault in the human body that kind of biases, biases us towards internal rotation. Does that make sense. Does the middle deltoid externally rotate? If it does, not well.

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Functional anatomy of the pectoralis major, latissimus dorsi, and teres major. Joint actions, location, pictures, and exercises for the pecs, lats, and teres major.

Pectoralis Major, Latissimus Dorsi and Teres Major: Video #10 of Introduction to Functional Anatomy

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