The piece of pie sign refers to an abnormal triangular appearance of the lunate on a PA image of the wrist representing either lunate dislocation or perilunate dislocation 1,2. A lateral image will help differentiate whether there is lunate or perilunate dislocation, with lunate dislocation demonstrating a spilt teacup sign. This is largely due to disruption of Gilula arcs and disruption of the spaces between the proximal and distal carpal bones.
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