 Okay, so let's look at the elbow. The elbow is our first synovial joint that we're going to dive into and look at in more detail. The elbow is actually, it's a hinge joint, it's a synovial joint, but it's actually a joint between three bones. What are the three bones involved? Your humerus, your radius, and your ulna. If you remember the anatomy of the humerus, at its distal end, we had the round capitulum that articulated with the head of the radius, and we also had that kind of pulley-looking trochlea that articulated with the trochlear notch of the ulna. So we have a place on the humerus for attachments of both the radius and the ulna. Now, we already talked about movements. We talked about the fact, we talked about pronation and supination. That movement is not happening at the elbow joint. That movement is kind of protected by one of our ligaments that we have to know, but it isn't, that's not an elbow movement. The elbow joint literally is nothing more than a hinge joint. It's pretty stable because it's stable. It doesn't have a lot of diversity of movement that's possible. Just the one, you know, it can flex and extend. Okay, so as far as anatomy of the elbow joint, we're sticking pretty simple here. We have two collateral ligaments. We have the radial collateral ligament. Ligaments are kind of like tendons except they connect two bones. And we have the ulnar collateral ligament, which is on the ulnar side, which is medial. And the ulnar collateral ligament is connecting the humerus to the ulna. Radial collateral ligament is on the lateral side. It's connecting humerus to radius. The other required structure that we have here is the annular ligament. And the annular ligament is an interesting one because the annular ligament is literally a ligament that surrounds the head of the radius. Now this is the elbow structure that is enabling supination and pronation because supination and pronation happens around that rotation of the radius. So the annular ligament is like holding the radius in place and allowing that to happen in all of our synovial joints. You're going to have an articular capsule. You're going to have a joint capsule. And look, here it is. If we were to cut the joint in half, you can see this space in between the two articulating bones. You can see your fibrous capsule here. You can see your synovial membrane here. Okay, that's not the color you use. Here's my synovial membrane. If I cut it open and peeled it back, I could totally touch the synovial membrane. If I can't open it up and peel it back, I can touch the fibrous layer of the joint capsule. Here's my space. My articular cartilage, you can see it. Okay, I kind of want to erase everything now. But maybe I'll just undo it all. Sure. Now you can see the articular cartilage is kind of whitish on the ends of this bone at the places where it articulates. Hey, that's good. That's the elbow joint. That's it. Let's do the shoulder joint next. Shoulder joint, not so easy.