Lunate Dislocation

Lateral radiograph of the wrist shows a volar dislocation of the lunate (arrow) relative to the position of the radius (R) and capitate (C).

Facts: Lunate Dislocation

• "Spilled teacup" sign (as seen on this lateral radiograph)
• Final stage of perilunate injuries
• Most severe form of perilunate injuries, highest degree of instability
• On lateral view of the wrist, the line drawn along the axis of distal radius, lunate and capitate should be almost straight. In this case, the line is disrupted because lunate is dislocated volarly.

Reference:

Kaewlai R, Avery LL, Asrani AV, et al. Multidetector CT of carpal injuries: anatomy, fractures, and fracture-dislocations. Radiographics 2008;28:1771-1784.