The distal radioulnar joint is a joint in the forearm that connects the two forearm bones, the radius (thumb side) and the ulna (little finger side), near the wrist.
The connection between the ulna and radius
At the lower end of the forearm, just before it meets the hand, the radius and ulna come together. This is exactly where the distal radioulnar joint sits. The word "distal" means "away from the centre of the body". "Radio" refers to the radius, and "ulnar" refers to the ulna. The joint itself is the movable point of contact between these two bones, right next to the wrist.
What does this joint do?
The distal radioulnar joint allows the two forearm bones to rotate against each other. This movement is important for turning the hand inward or outward, for example when turning a key in a lock or flipping a glass upside down. Without this joint, this rotating movement, which is known in medical terms as pronation and supination, would not be possible.
Through its teamwork with the wrist, the hand gains a wide range of movement. Everyday activities such as writing, using a screwdriver, or opening a bottle only work because the distal radioulnar joint plays its part.
Structure and position
The joint sits at the lower end of the forearm, right at the border with the wrist. Here, the rounded head of the ulna rests in a small notch in the radius. Between the two bones sits a joint capsule, which protects the joint and keeps movement smooth. Ligaments and a small disc of cartilage (called the articular disc, or discus articularis) also help to stabilise this connection.
The distal radioulnar joint is a true pivot joint. It works closely with the proximal radioulnar joint, which sits closer to the elbow. Only when both joints work together is the full movement of the forearm possible.
When does this term come up?
In medical reports, X-ray findings, or letters from doctors, the distal radioulnar joint is often mentioned when there are injuries, pain, or restricted movement in the forearm or wrist area. After fractures of the radius or ulna, this joint also plays an important role, because it is key to restoring full function.
Sometimes the joint is also affected when the wrist has been sprained or overloaded. In such cases, there may be swelling, pain, or limited rotation. The term itself, however, simply describes an anatomical structure, not a condition or diagnosis.
What does this mean for you?
If the distal radioulnar joint is mentioned in a report or doctor's letter, it simply refers to the area at the lower end of the forearm where the radius and ulna meet. Most of the time, the joint is only mentioned to describe the exact location of an injury, swelling, or other finding.
As long as there is no pain, restricted movement, or other symptoms, there is no reason to worry. The distal radioulnar joint is a completely normal part of the forearm and keeps the hand moving freely.
Summary
The distal radioulnar joint is the joint between the radius and ulna at the point where the forearm meets the wrist. It allows the hand to rotate and is essential for many everyday movements. In medical texts, the term usually appears to describe the exact location of symptoms or injuries.
