Occult fractures are those that are not visible on imaging, most commonly plain radiographs and sometimes CT, either due to lack of displacement or limitations of the imaging study. There may be clinical signs of a fracture without one actually being seen. MRI or nuclear medicine studies are sometimes required to make the diagnosis.
Technically any fracture may be occult, but classic examples include:
- distal radius fracture (pronator quadratus fat pad sign may be positive)
- neck of femur fracture
- radial head fracture (sail sign may be positive)
- scaphoid fracture
- supracondylar fracture in children (loss of alignment may be the only sign)