ABSTRACT
Introduction : The squamous portion of the occipital bone consists of two different parts: the upper interparietal and the lower supraoccipital. The interparietal part may remain separated from the supraoccipital by a suture; it is then called the interparietal or Inca bone. Aim : In this study, incidence of interparietal bone has been estimated and compared with the other observations. Methodology : Total 105 cadaveric dry human skulls were examined to determine incidence of interparietal bone. Observations : The skulls which were observed, displayed many variations in the occipital region. In 7 cases, single or multiple separated bones were observed. In 4 cases (3.81%), the lower edge of these additional bones was situated above the external occipital protuberance and such bones could be classified as interparietal bones. In 3 cases (2.86%), the lower edge of these additional bones was much higher (between the lambda region and the highest nuchal line). The later can be classified as preinterparietal. Importance : Knowledge of interparietal bone is important for the radiologists, neurosurgeons, anthropologists, orthopedics and forensic experts to avoid misdiagnosis.