Radiocarpal Ligaments

The radiocarpal ligaments are extrinsic ligaments that connect the radius to the carpal bones. They can be divided into palmar, dorsal, and lateral.

Palmar

• Radioscaphocapitate ligament (RSC): The RSC ligament originates from the palmar and radial aspects of the radial styloid process in association with the radiolunotriquetral (RLT) fibers (see below). It runs obliquely across the carpus, passing through a groove in the waist of the scaphoid, stopping to attach to the palmar aspect of the distal pole of the scaphoid, before terminating on the center of the palmar aspect of the capitate. Course best seen in the sagittal plane. Cross section best seen in the transverse plane.
  
  
• Radiolunotriquetral (long radiolunate) ligament (RLT): The RLT fibers originate with and to the ulnar side of the fibers of the RSC on the palmar aspect of the radial styloid process. Its fibers pass through the aforementioned groove of the scaphoid waist, proximal to the RSC fibers, stopping to insert on the palmar aspect of the lunate before heading out to attach along the radial side of the pisotriquetral joint. Course best seen in the transverse plane. Cross section best seen in the sagittal plane.
  
  
• Short radiolunate ligament: The short radiolunate ligament gets short-changed because it is not well-seen on MRI.
  
  
• Radioscapholunate ligament: The radioscapholunate "ligament" is most likely a mesocapsule for neurovascular branches from the distal radial arterial arch. It originates from the palmar aspect of the distal radius and inserts along the proximal palmar aspect of the scapholunate ligament. On MRI, it doesn't appear hypointense on T1-weighted images.
  
  

Dorsal

• Dorsal radiotriquetral ligament (dRT): The radiotriquetral ligament, also known as the dorsal radiocarpal, ligament originates on the dorsal aspect of the distal radius, crosses over the lunate, before attaching to the dorsal aspect of the triquetrum.Course best seen in the transverse plane. Cross section best seen in the sagittal plane.
  
  
• Dorsal radiolunate ligament (dRL): The dorsal radiolunate ligament forms from the fibers of the dorsal radioulnar (dRU) ligament that insert onto the dorsal aspect of the lunate.

Lateral

• Radial collateral ligament (RC): The radial collateral ligament originates on the tip of the radial styloid process lateral to the origin of the RSC and RLT fibers and inserts onto the radial aspect of the scaphoid waist before blending with the capsule to insert into the trapezium. Course best seen in the coronal plane. Cross section best seen in the transverse plane.

References

Theumann NH, Pfirrmann CW, Antonio GE, Chung CB, Gilula LA, Trudell DJ, Resnick D. Extrinsic carpal ligaments: normal MR arthrographic appearance in cadavers. Radiology. 2003 Jan;226(1):171-9.