The primary function of the distal radioulnar joint is to facilitate the pronation and supination of the forearm. These movements are essential for a variety of daily activities, such as turning a doorknob or using a screwdriver. When you turn your palm up (supination) or down (pronation), the radius rotates around the ulna at the distal radioulnar joint. This joint's unique structure, with a disc-shaped head of the ulna fitting into the notch of the radius, allows for smooth and efficient movement. Additionally, this joint helps maintain forearm stability and contributes to the overall functionality of the wrist and hand.