Abnormal lunate bone morphology Triangular lunate bone 2024-12-08T19:44:56Z A disruption of the greater and lesser arcs of the lunate bone, with the lunate having a triangular silhouette, know as the piece of pie sign. Often caused by falling on an outstretched hand, patients will have tenderness to palpation over the dorsum of the wrist and may have sensory deficits in the median nerve distribution. See Figure 3 of PMID:23616330. Piece of pie sign of lunate bone