Resumo
The skull, the most complicated bony structure in the body, is made up of twenty-two bony pieces that are approximated at the sutures. Establishment of accessory ossification centers in the sutures result in the formation of Inca and Wormian bones. This is a case report detailing the occurrence of an unusual bone (inca bone) in posterior skull with asymmetry in size and shape of the oval and carotid foramina at the base of the skull. Following bone maceration of dissected cadavers in the Department of Anatomy, University of Ibadan, Nigeria, we observed multiple anomalies in an adult male Nigerian skull. The skull presented with an Inca bone, complete ostosis of sagittal & lambdoidal sutures, right infraorbital fissure, left infraorbital foramen with adjoining canal, bilateral supraorbital notches, large non-symmetrical right foramen ovale and carotid foramen, thickened left superior temporal line and straightening of the mid 1/3rd of the coronal suture.
Awareness of the existence of Inca bones, complete ostosis of sagittal and lambdoidal sutures and thickened superior temporal lines by radiologists is important in order to avoid misdiagnosing them for fractures. The occurrence of inca bones, completely fused sutures and thickened cranial bone markings pose problems to surgical access to the cranial cavity during neurosurgical procedures. However, they can be useful tools in anthropometric and forensic identification of human beings