 Hey everybody, Dr. O here. Let's talk about the radius and ulna here in your forearm. First things I think of when I look at this picture is notice that the ulna starts big proximally and then tapers and gets smaller, whereas the radius is going to start small proximally and then gets larger as it travels down to the wrist. When I'm holding these two bones, here's the things that I think of as far as the key to remember it. The head of the radius is a circle, right? The radius is half the diameter of a circle. So the radius has a circle on it and the ulna, you can't see it very well here but that trochlear notch is shaped like a U. So if you're holding these two bones, the ulna has a U on it. The radius has a circle on it. That's how I remember them. All right, let's start with the radius. We have that head of the radius, which we already said that circular structure there plays a big role in pronation and supination movements. The radial tuberosity there is going to be an insertion point for the bicep tendon. Distantly, you have the styloid process of the radius. You'll see that both the radius and ulna have a styloid process that kind of encases your wrist there. So those are going to be the key things on the radius. So the head of the radius, the radial tuberosity, and the saloid process of the radius there. We also do have the ulnar notch of the radius where the radius and ulna come together approximately. The ulna, you have that olecranon process and coronoid process forming that trochlear notch that does look like a U. So I already said olecranon and coronoid process, they fit into the olecranon and coronoid fossa of the humerus. We have the head of the ulna there. The radial notch, remember the radius has an ulnar notch and the ulna has a radial notch. And then we have the styloid process, which I already mentioned before, kind of brackets the carbobones of your wrist down there. And then you see the last thing, the note here, the proximal and distal radial ulnar joints are going to be the two joints that hold them together with an interosseous membrane between the two, which allows for all sorts of movement, which is why we can move our forearm so much. All right. So that is the radius and ulna. I hope this helps. Have a wonderful day. Be blessed.