Teaching institutions are turning to replicas for elementary as well as advanced instruction in human anatomy. Bone Clones® human skulls are reproduced (real-sized) from carefully selected natural bone originals, chosen to represent the organic elements necessary for study – whether it be advanced human anatomy, determination of ancestry, evidence of pathology, or clues to human identification in a forensic setting. Skulls with removable calvaria have a spring-hinged jaw. All other skulls are 2-part, unhinged, skulls.