Ligament · Hand

Dorsal radioulnar ligament

Ligamentum radioulnare dorsale

One of the two thickened borders that hold the far ends of the radius and ulna together. It runs along the dorsal edge of the ulnar notch of the radius to the base of the ulnar styloid, and it is not a free cord but the back border of the triangular fibrocartilage complex — the disc-and-ligament sling slung from the radius across the head of the ulna. With its palmar twin it keeps the ulnar head seated in the notch of the radius while the forearm turns the palm up and down. Left unsupported, that head can drift forwards or backwards during rotation, which is why the two ligaments are almost always described as a pair.