Perilunate dislocation 

or carpal ligamentous injury stage II – best viewed on the lateral view of the wrist

Normally, you can see 3 C’s as the lunate (cup)”sits” on the articular surface of the radius (plate), and the capitate (apple) “sits” on the articular surface of the lunate.

With perilunate dislocation:

– the capitate is posteriorly dislocated

– the lunate remains articulated with the radius

– on the PA view, the capitolunate joint space is lost as the bones overlap each other, and the 3 arcs formed by the carpal bones are disrupted

This injury can be associated with:

– scaphoid fracture (transscaphoid perilunate dislocation)

– ulnar styloid fractures

– capitate fracture (transscaphoid transcapitate perilunate dislocation)

– median nerve injury

ED management is closed reduction and immobilization in a long arm splint. They need urgent (same day) Orthopaedics referral for reduction / repair.