One of the most beautiful muscles that you can look at in a cadaavver lab, at least in my humble opinion, is this muscle that you can see here called the pec duralis major. I mean, look at how incredible this muscle is. These fibers fanning out onto the chest wall and then converging onto the humorris. Like I said, it's beautiful. Now, I'm going to assume that many other people think that this muscle is desirable to look at. Granted, this is usually when it's covered up with skin, fascia, and breast tissue in the case of females, which in that case, it makes it a little bit more tricky to observe, but people like how this muscle looks because people are constantly working it out to make it larger and more aesthetically appealing. And working out the pecs just for looks is great and all, and we'll definitely address how to do that, but it is also great just to strengthen this muscle from a functional standpoint. And this also gives females a reason to strengthen this muscle. So today we're going to discuss how this muscle really functions, which will then help us to understand what exercise choices are best for working out this muscle. We'll talk about how it relates to the overlying tissue like the breast tissue and skin and get into some protocols that you can apply to your exercise routine based upon your hopes, desires, and dreams for your own pectoralis major. I'm Jonathan Ven with the Institute of Human Anatomy, and it's time to get into this anatomical awesomeness. So let's start by going over the anatomy of the pec major because again this will really help us to understand how it functions and how we can best exercise it. Now you may have heard of people talking about working out the upper pec, the mid pec and the lower pec. And again if we take a look at this beautiful fan-shaped muscle, we can see that we can break it down into three parts or three heads. We have the clavvicular head attaching to the medial half of the clavicle. the sternoccal head attaching to the sternum and the second through sixth costal cartilagages and costal just means rib. So the second through sixth rib cartilagages and the third part is the abdominal head. Now the abdominal head can vary a bit from person to person. It can be larger and smaller in some people and even be completely absent. So some anatomy books don't even mention it. But on this particular body, you could say that it has a small abdominal head because the abdominal head are these fibers that attach to the rectus sheath, which is this white connective tissue sheep that you can see here. Then we've removed part of it here and here and then kept the majority of it intact down below. And the rectus sheath covers the rectus abdominis. And rectus abdominis is just the fancy pants name for the six-pack muscle. and we've only exposed a few blocks of the six-pack muscle and then again kept the rectus sheath intact covering up the majority of that muscle. Now, if someone doesn't have an abdominal head or it's less prominent, it's not really a big deal. You can still build big strong pecs and it still doesn't mean that there wouldn't be a benefit to working out the lower pecs. And I'll explain that a little bit later on. But what is also really cool about the architecture of this fan shaped muscle is that all three heads will converge to insert onto the humorris specifically on this lateral lip of this groove called the intertubercular groove that you can see on Jeffrey. Now one thing that I always try to get my anatomy students to pay attention to is the fiber orientation of a muscle. Meaning what direction are the fibers running? And as you can see with the pec major the fibers are running in this direction. And this is important because when you can see the fiber orientation, you can kind of visualize and get a sense of the movement that the muscle is going to perform when those fibers shorten during the contraction. And this takes us to the functions of the pectoralis major. Now, as a whole, all three heads of the pec major are going to perform a few different movements together. Internal rotation of the shoulder, which looks like this. And again, just imagine those fibers shortening, causing the shoulder to rotate internally. All three heads will also do adduction of the shoulder as well as horizontal adduction of the shoulder. And as you can clearly see, horizontal adduction is very functionally important to performing one of the most loving movements that a human can produce, and that is hugging with adding flexion of the elbows with the biceps to complete your hug. So clearly strengthening this muscle is great for increasing the amount of love you can show someone. And clearly we can all see that I'm a big nerd, but we'll get to the non-hugging exercises in just a second. But I do want to mention a function specific to the clavvicular head. The clavvicular head can also perform flexion of the shoulder which looks like this. Now technically the sternal costal head can assist with extension of the shoulder if the shoulder is already in a flexed position. So doing this, that's not really important to our story because this is certainly not the prime movement produced by the pec. But I mention it because we have some anatomy nerds out there that like to have every little detail. So now that we know how the pectoralis major functions, let's apply this knowledge to choosing the most effective chest exercises or what you could consider the best bang forbuck chest exercises. An effective bang forbuck chest exercise would be one that targets all three heads. Now remember from what we just learned, all three heads of the pec major participated in internal rotation, adduction, and horizontal adduction. So therefore, we should choose an exercise that utilizes one of those movements. You technically could use internal rotation to work out the pec with bands or a cable machine, but that can sometimes get a little tricky from a loading standpoint, and it is definitely limited on the range of motion and therefore limiting the amount of stretch or eccentric demand you could place upon the pec. And so using an exercise that utilizes horizontal adduction is a much better choice, especially if you start further back, you're going to get much more range of motion and a greater demand placed upon this muscle and therefore a better overall stimulus for strength and size. And there are three exercises that do a really good job of this. Two of them are likely not going to surprise you. And those two exercises are the bench press and push-up. And the third I'll mention in just a second. But you might be thinking, Jonathan, horizontal adduction looks nothing like a bench press or a push-up. Well, it actually kind of does. The differences with a bench press and a push-up is that you make it a compound movement because you also add the elbow joint and therefore the triceps, your shoulder joint, and therefore the work that the pec does goes through the exact same range of motion regardless of elbow position. Watch without the elbow involved. Looks like so. And then when I do get the elbow involved, all I do is simply this. And it looks quite a bit like a bench press or a push-up. And my shoulder moves in the exact same way. I just now get the added benefit of working my triceps. And another advantage of this is, especially with the barbell bench press or the dumbbell bench press, you can very easily tap into the principle of progressive overload because it is very easy to add a substantial amount of weight to the bar or add heavier dumbbells as you get stronger. And just a little bit of a tip, especially with the barbell and dumbbell bench press, you want to keep your shoulder blades or your scapula depressed and retracted. So in other words, it would look something like this. You want to bring your shoulder blades together and downward. And the reason for this is this creates a little bit more of a stable base and it makes your shoulder a little bit happier and safer with these greater range of motion movements. Now, I will come back to some more details on working the upper pec, mid pec, and lower pec with the presses in just a second, but I do want to mention that third exercise. The third exercise, dumbbell flies. And you could technically do cable flies as well, but this exercise is effective for very similar reasons that the bench press and push-up are very effective. You get that greater full range of motion through that horizontal adduction. And you'd want to utilize the same cues with your scapula that we discussed with the bench press retracted and depressed to stabilize the shoulder girdle. And you want to do these in a slow, controlled manner because having the weight further out from the body, you want to make sure that you maintain that stable connection with your scapular muscles, making it less likely that you'll tweak your shoulder. Now, you could make an argument that from a range of motion standpoint, the flies are even better than the bench press or push-up because you get a little bit more range of motion at that end point, that nice little contraction at the end. And that's especially true with compared to say like the barbell bench press because your hands are fixed and kind of just stuck to the bar. But with the dumbbell bench press, you could come a little bit further and get a little bit more adduction similar to the fly, especially if you were to supenate at the end to kind of get the dumbbells out of their way. But again, all three of these exercises are great for building pec strength and size. And I do feel like I need to say this does not mean that there aren't any other effective pec exercises. We again picked these exercises because they fire well into all three heads. You get a full range of motion and they are all fairly simple to execute. But I'm definitely interested in your opinion of other great exercises. So, please feel free to put those in the comments. But most people can get away with having great pecs with just using these exercises. But for those who are more concerned with making sure their pecs are as pretty and balanced as possible, you may want to target some specific areas of your pecs, like the upper, mid, and lower portions. And in order to do that, we need to start messing with or changing the joint angle, which will allow us to fire into some of the heads or fibers of the pecs a little bit more thoroughly. So do a little experiment with me here. Let's do this bench press type motion here and hold this pec and keep it contracted. And while you're contracting this pec, feel in there, dig your hand in there. And then while your hands in there, change the joint angle. Move up, move down. And you should notice that the tension throughout the muscle changes based upon the joint angle. And the reason for that is we're essentially changing the demands on different fibers throughout the pec muscle. Some are going to be more lengthened. Some of the fibers are going to be more shortened. And earlier I mentioned the fiber orientation, but I was pretty basic with it. I essentially said earlier on that the fibers are pretty much all going over in this direction to attach to the humorris. But if we look a bit more closely and analyze the fiber orientation in more detail, we can see the lower fibers from say like the abdominal head and the lower fibers of the sternal costal head are moving in this direction where more of the central fibers of that sternal costal head. Those are more of the true kind of horizontally oriented fibers. And then if we come up to the clavvicular head, you can see those fibers are angled more downward. And so if we go into certain joint angles like say in this position like we would be on a decline bench press, this is going to fire more into those lower fibers like the abdominal head and the lower fibers of that sternal costal head. And if we go into say like this joint position, like on a flat bench press, that's going to fire in more into those central fibers, those true kind of horizontal fibers of that sternal costal head. And then if we go up even further, like the position we'd be on an incline bench press, that will fire more into those clavicular head fibers up here. Now, you've probably noticed that I have been somewhat careful with my language saying firing more into because say if we're like in the position of an incline bench press. Yes, it's going to be firing more into those upper clavvicular fibers, but it doesn't mean none of the other lower fibers aren't active. It's just again we're placing a greater demand on certain fibers based upon that joint angle or that position of our shoulder joint. And so these are additional exercises that someone could incorporate to their chest routine if they're concerned about building up certain areas of their pec, say like the lower pec versus the mid pec and the upper pec. So now let's discuss the differences between male versus female chest anatomy because I have had students ask in anatomy classes, do females have a pectoralis major similar to males? And so let's find out because we have two bodies here, one male and one female. This body that we've mostly been viewing throughout the video is actually a male body. And so in this case, the pectoralis major would only be covered up by some fascial tissue, the subcutaneous layer, which is the fatty layer. And keep in mind that subcutaneous layer is quite variable from person to person. It can be millimeters thick all the way up to inches thick. And if it's thicker, it's going to obviously be a little bit harder to see the definition of the pectoralis major. And on top of the fatty layer, you'd have the epidermis and dermis pretty much making up the skin. Now over here on this female body, take a look at this cool cadaavver dissection. We've removed all those superficial tissues and you can definitely see females have a pectoralis major just like males. The difference in this case is we're going to have that fascial tissue and then the hypodermis or subcutaneous layer which is that fatty layer. And you can kind of get a sense of how thick that is on this particular body because it's in a bit different stage of dissection. But we've removed the breast tissue that would be essentially mixed in or in that plane of space of the hypodermis or that subcutaneous layer. And then on top of that we'd have the epidermis and dermis constituting the skin. And so, yes, females have a pectoralis major. And it is more difficult to visualize that muscle for the average female, but that doesn't mean females wouldn't have a benefit from working this out, especially from a strength perspective because doing bench press, flies, all the exercises we've talked about will strengthen that muscle in females. Granted, again, it's just going to be deep to that breast tissue. And that's going to be great from a functional standpoint to having greater strength and for all of us to be better huggers. One of my hopes with every video we create is not only to make you a better hugger, but to inspire you to be a lifelong learner. And if you take a little bit of time to learn something new each day over days, weeks, months, and years, you'll build an incredible base of knowledge. And to help you with this, I have something that you could try for free. And that is the sponsor of today's video, Brilliant. 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