Short radiolunate ligament

The short radiolunate ligament (SRL) is one of the palmar (volar) extrinsic radiocarpal ligaments, connecting the distal radius to the lunate.

• Origin and insertion: Arises from the volar rim of the distal radius at the palmar edge of the lunate fossa—ulnar to the long radiolunate ligament and the radioscapholunate neurovascular bundle, close to the volar fibers of the triangular fibrocartilage complex—and inserts on the proximal palmar surface of the lunate. It is a relatively short structure (~9.2 mm in length) and is strongly conjoined with the palmar radioulnar ligament of the TFCC.

• Anatomic classification: It is one of the three principal palmar radiocarpal ligaments (with the radioscaphocapitate and long radiolunate ligaments), and like the others is intracapsular—enveloped within a continuous superficial fibrous stratum and a deep synovial stratum.

• Function: Serves as a palmar stabilizer of the lunate, helping to inhibit lunate dorsiflexion, and—together with the long radiolunate and dorsal radiocarpal ligaments—acts as an important restraint against ulnar translation of the carpus.

• Imaging note: On MRI it is less consistently identified than the radioscaphocapitate and long radiolunate ligaments, and its avulsion is an uncommon, easily missed injury that can lead to chronic wrist instability.