The radioscaphocapitate ligament is the most radial and most important volar extrinsic wrist ligament, providing the sling that prevents ulnar translation of the carpus and supports the scaphoid. It is the last ligament to fail in progressive carpal instability — its rupture produces the pan-carpal ulnar translation of advanced rheumatoid arthritis. The scaphoid space between the RSC and the long radiolunate ligament is the relatively avascular space of Poirier through which the carpus dislocates in perilunate injuries.
| Origin | Radial styloid (most radial extrinsic wrist ligament) |
|---|---|
| Insertion | Waist of the scaphoid (passes over it) and body of the capitate |
| Actions | Restrains ulnar carpal translation; acts as a sling supporting the scaphoid against the radius; the most important volar extrinsic wrist ligament |
|---|
The RSC ligament is the floor of the space of Poirier — the weak point of the volar wrist capsule through which the capitate dislocates in perilunate dislocation. During dorsal perilunate fracture-dislocation repair, the volar space of Poirier is repaired by imbrication of the RSC to the long radiolunate ligament. RSC ligament reconstruction prevents ulnar carpal drift in rheumatoid arthritis.
RSC ligament disruption at the space of Poirier in perilunate dislocation repaired by volar capsule imbrication during reduction.
