Normal variant mimicking a depressed skull fracture

Inca bones are a recognised anatomical variant of the interparietal part of the occipital bone. They can be variable in appearance and along with other normal variants and artefacts, can be mistaken for skull fractures. A knowledge of anatomical variants which may mimic injury is important especially in the setting of post mortem examinations and cases of suspected non-accidental injury. This case report reviews a post mortem skeletal survey and CT head examination in an infant who presented with sudden and unexplained death. An unusually large, and depressed abnormality of the skull was found with a differential diagnosis of an unexplained, depressed skull fracture or an unusual variant of an Inca bone. The imaging and post-mortem findings are reviewed.