Your elbow lets you throw, lift, swing, and hug. You can do all this because it’s a complicated joint. And that means there are a lot of ways things can go wrong. Your elbow’s a joint formed where three bones come together -- your upper arm bone, called the humerus, and the ulna and the radius, the two bones that make up your forearm. Each bone has cartilage on the end, which helps them slide against each other and absorb shocks. They’re lashed into place with tough tissues called ligaments. And your tendons connect your bones to muscles to allow you to move your arm in different ways. If anything happens to any of these parts, not to mention the nerves and blood vessels around them, it can cause you pain.