X-ray and CT of carpal boss

The lateral x-ray and CT examination reveal a carpal boss. This 40-year-old male presented with pain following trauma. A lateral radiograph (A) demonstrates a bony protuberance at the dorsal aspect of the capitate-3rd metacarpal joint (arrow). A multiplanar CT examination (B and C) was subsequently performed to evaluate for a radiographically occult fracture which more clearly demonstrates this finding, consistent with a carpal boss.