 Doggies, the rotator cuff muscles, there's four of them. We've already looked at them when we looked at the shoulder joint. But now we're just going to take it a little bit further and look at their attachments so that we can be sure that we're like, oh, we know how the rotator cuff muscles are carrying out their function now. They all have major actions. And you, more power to you if you would like to memorize all of those or learn all of those different actions that they have. And the actions are very similar. You could sort them into piles. It isn't crazy to know their actions. But what I want you to know is that they stabilize the shoulder joint. And that's the piece that I want you to know. So they are literally holding onto the humerus, the head of the humerus, and holding it into the glenoid fossa. And those muscles surround the head of the humerus and attach to various places on the humerus and attach to various places on the scapula and keep those two together. I mean, the shoulder joint is pretty mobile. It's the most mobile joint in your body. And because it's so mobile, it's also the least stable joint. So thank you, rotator cuff muscles, which often take a beating because of the incredible mobility of the shoulder joint. Everybody, hug your shoulders right now. Thank you very much. Okay, so our action for these guys is just going to be speak to stabilize the shoulder joint. That's what we're going to do. Now, before we even go look at these guys, this sorting process is easy. There is one muscle that attaches to the lesser tubercle of the humerus. One. All the rest of them attach to greater tubercle. All of them. So subscapularis attaches to the lesser tubercle. Now, think about that for a second. That totally works for me. Subscapularis, where is the other attachment going to be? This subscapular fossa? Subscapular, the infraspinous fossa. It's a fossa. I hope that it's the subscapular fossa because I won't tell you how late it is right now, but that is my excuse that it's really late right now. Subscapular fossa. Since you already know the scapula and all the parts of the scapula, knowing the rotator cuff muscles and their attachments is easy, easy peasy. Supraspinatus attaches to the supraspinus. Fossa. Infraspinatus, infra, oh geez, spinous fossa. And teres minor. Remember teres minor? We were looking at, we saw that trapezius, okay, I think I just have to go show you teres minor so that we can see where it actually is. Remember, teres major was inferior, teres minor was superior. They both attach to the medial border of the scapula. Teres minor attaches superior to teres major. And then the long head of triceps slips between them. So what, medial edge, medial border of the scapula? Wow, I can totally do this, I really can't, I promise. Medial border of the scapula. And just for perspective, superior to teres major. Okay, let's go look at them all. This is teres minor. Dude, we don't even have to shift gears. We've got, who's this? Below the spine, spine, I said spine. Infraspinus, I mean infraspinatus attached to the infraspinus fossa. And then who's this? Supraspinatus. These are actually nice and easy. And then you tell me, think, where are we going to look? Where do you see subscapularis from here? What are you going to expect to have happen? You've got to look from the anterior surface in order to see the subscapularis, which is this thing right here. And does it make sense when you think of subscapularis being on the anterior surface of the scapula, right? So when you're looking at the anterior aspect of a human, you can see their subscapularis through their ribs. You can see how their guts and stuff, that's cool. Makes sense to me that it's going to attach to the more medial bump. It's going to attach to the, what? The lesser tubercle. I knew it would come out of there eventually. It attaches to the lesser tubercle and it's the only one that does that because it's the only one that we need to see from the anterior surface. There's all sorts of ways that you can remember this. Now our shoulder joint is nice and stable. If you rotate or cuff, let's talk about the muscles that are going to move the forearm. I'll be right back.