A Human Skull with a Tripartite Inca Bone: A Case Report

An adult human skull was discovered in a college osteological collection presenting with two Inca bones. Inca bones or interparietal (supernumerary) bones are rarely seen among dry human skulls. Their frequency of presentation is much less than that of sutural or Wormian bones. Inca bones or interparietal (supernumerary) bones are accepted as normal variants most often found in the occipitoparietal region of the skull. Their characteristic shape, a triangle, resembles a monument design of the Inca tribe of South America and Latin America. The significance of the presence of these variants is that Inca bones or interparietal bones may be mistaken for a skull fracture. They may also be very useful in forensic identification of an unknown individual.