The elbow is a basic hinge joint. It flexes and extends the two forearm bones. Let's look closer at the radial side of the elbow. In the image below, look at how the radius connects to the humerus. When the elbow bends or straightens, the radius articulates with the humerus in a way that allows it to rotate at the same time. This simple design allows us to use our hands any way we want to. For example, you can pick up an apple with your palm down, elbow extended and turn your palm up while bending the elbow as you bring the apple to your mouth. It’s a simple, everyday movement we don’t think about until we have pain or limitation.

The structures involved in bending the elbow and rotating the forearm allow us to perform a multitude of tasks. Take a moment to appreciate this functional design.

Next we’ll take a closer look at how the radius and ulna bones interact when we rotate our forearm.