Between the radius and ulna there exists a fibrous joint that permits some movement. Which joint is this?

• A. Suture
• B. Interosseous membrane
• C. Epiphyseal plate
• D. Intervertebral disc

Answer: (B)

Between the radius and ulna, a fibrous connection called an interosseous membrane forms a syndesmosis. This broad, fibrous sheet binds the two long bones along their shafts, allowing only a small amount of movement while still providing stability. In the forearm, this membrane plays a crucial role during rotation: as the radius crosses over the ulna during pronation and then returns during supination, the membrane tautens and helps transmit load between the bones, distributing forces from the wrist up toward the elbow. This differs from sutures, which are immovable joints between skull bones; from the epiphyseal plate, which is a cartilaginous growth region; and from the intervertebral disc, a cartilaginous joint between vertebrae.