Long radiolunate ligament
The long radiolunate ligament is a large intracapsular, extrinsic palmar radiocarpal ligament and a volar stabilizer of the wrist .
Terminology
The long radiolunate ligament is also known as 'radiolunotriquetral ligament', 'volar radiotriquetral ligament' or 'volar radiolunate ligament'.
Gross anatomy
The long radiolunate ligament forms a part of the volar radiocarpal joint capsule and connects the palmar surface of the radial scaphoid fossa with the lunate and triquetral bone. It also runs in an oblique orientation parallel to and separated from the radioscaphocapitate ligament by the interligament sulcus .
Attachments
The long radiolunate ligament originates ulnar to the origin of the radioscaphocapitate ligament from the volar margin of the scaphoid fossa of the distal radius .
It covers the proximal pole of the scaphoid bone and inserts to the radial surface of the lunate bone. From there, fibers run and insert at the palmar radial surface of the triquetral bone. It blends with fibers from the lunotriquetral interosseous ligament .
Radiographic features
Ultrasound
The long radiolunate ligament can be visualized on ultrasound with the transducer placed at the volar aspect of the radial side of the slightly extended wrist in the longitudinal plane and then rotated towards the triquetral bone. The long axis of the ligament is displayed as an echogenic, fibrillary structure attaching the distal radius to the lunate and triquetral bone .
MRI
The long radiolunate ligament is easily visualized on MRI. Similar to the radioscaphocapitate ligament it can be best appreciated on coronal or sagittal images or 3D images and usually has a hypointense appearance . The interligament sulcus can be delineated as a fluid intense structure. It also shows a striated appearance on coronal images.
Related pathology
The ligament is most likely injured or involved in the following pathologic conditions :
- nondissociative carpal instability (CIND)
- ulnar translocation (type 1 and type 2): rheumatoid arthritis, Madelung deformity
- radial translocation
- radiocarpal translocation
See also
