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Figure 19c.   Hamatolunate impaction syndrome in a 36-year-old man. (a) Posteroanterior radiograph of the wrist in full ulnar deviation shows abutment of the hamate and lunate bones (arrow). (b, c) Coronal T1-weighted (500/15) (b) and fat-suppressed T2-weighted (3,000/50) (c) MR images show type II lunate bone with adjacent marrow edema of the hamate bone (arrow) and severe chondromalacia of the hamate bone, a finding that was proved at arthroscopy. Note the linear defect in the proximal aspect of the lunate bone (arrowhead), a finding that suggests a vascular groove.