A Study of Interparietal Bone in 105 Human Skulls of Gujarat Population.

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.

Medicolegal importance of inca bone in forensic.

Skull is usually available human bone for establishing personal identity. Presence of Inca bone in human skull is one such feature that may be identified on radiological examination and if earlier recorded help in establishing the identity of deceased. Complete division of membranous and cartilaginous part of occipital bone by a transverse suture extending between the two lambdoid sutures at the level of highest nuchal line above the external occipital protuberance, results in rare cranial variation presenting as Inca bone.During medicolegal examination of one male skull at Madhya Pradesh Medicolegal Institute Bhopal, presence of Inca bone was found. The interparietal bone is formed by a part of the squamous occipital bone bounded by two lambdoid sutures on two sides and additional longitudinal suture on both sides between lambdoid suture and external occipital protuberance forming diamond shaped Os Incae Centrale that can also be considered as intra-occipital bone. Such rare findings have significant anthropological and embryological basis. Specific anatomical feature if earlier documented in the clinico-radio-pathological reports of the deceased provides opportunity for establishing the identity.

Frecuencia del hueso interparietal o incaico en cráneos atácamenos (Lican antai) prehispánicos del norte de Chile / Frequency of interparietal bone or inca bone in pre-hispanic Atacamenos (Lican Antai) skulls of the north of Chile

El hueso interparietal se considera un hueso intercalar originado de centros independientes de osificación y rodeado por sus propias suturas. Se encontró en fósiles homínidos y humanos tempranos. Se cree que el occipucio sufre transformaciones por mutaciones al iniciarse la evolución humana reforzando esta teoría las variaciones suturales que presenta el occipital. Sería un rasgo genéticamente dominante, propuesta ratificada por estudios experimentales. Se observa con variadas formas según la fusión de los núcleos de osificación, por lo que todos los huesos ubicados en la zona de la escama del occipital no se pueden clasificar como suturales o wormianos y deben considerarse como parte del hueso interparietal. Tratando de confirmar la alta frecuencia obtenida en investigaciones anteriores realizadas en cráneos de individuos originarios del norte de Chile, se analizaron 83 cráneos de atacamenos prehispánicos de ambos sexos, seleccionados al azar entre 293 individuos exhumados del cementerio Coyo-Oriente, datados entre 300-1200 D.C período post-Tiwanaku y que forman parte del Museo R.P. Gustavo Le Paige en San Pedro de Atacama, dependiente del Instituto de Investigaciones Arqueológicas de la Universidad Católica del Norte, que fueron fotografiados en todas sus normas anatómicas y que se midieron paras obtener el índice craneal o cefálico. El hueso interparietal está presente en 23 de 83 cráneos, con una frecuencia de 27,71 por ciento, sin diferencias estadísticas significativas al 95 por ciento con investigaciones realizadas en cráneos de origen étnico similar y en otras etnias que presentan alta frecuencia de hueso interparietal. Por el contrario, se encontraron diferencias estadísticamente significativas al 95 por ciento con frecuencias determinadas en cráneos europeos caucásicos y euroasiáticos. Los autores integraron las tablas clasificatorias de Kadanoff y Hanihara-Ishida, para obtener una tabla modificada que permitiera clasificar ...

The interparietal bone is considered an intercalary bone originated by independent ossification centers and surrounded by its own sutures. It is found in early hominids and human fossils. It is believed that the occipital bone undergoes transformations by mutations at the beginning of human evolution. Reinforcing this theory are the suture variations that presents the occipital bone. It would be a dominant genetic characteristic, proposal ratified by experimental studies. It is observed with varied forms according to the fusion of the ossification nuclei; reason why all the bones located in the zone of the occipital flake cannot be classified as sutures or wormians and must be considered part of the interparietal bone. Trying to confirm the high frequency obtained in previous investigations realized in skulls of original individuals of the north of Chile, we analyzed 83 skulls of pre-Hispanic atácamenos (lican antai) of both sexes, selected at random between 293 individuals of the Coyo-Orient cementery, dated between 300-1200 A.C, post-Tiwanaku period and these remains are part of R.P Gustavo Le Paige's Museum in San Pedro de Atacama, which is part of the Institute of Archaeological Investigations of the North Catholic University. The remains were photographed in all anatomical norms and that were measured to obtain the cranial or cephalic Index. The interparietal bone is present in 23 of 83 skulls, with a frequency of 27.71 percent, without significant statistical differences to 95 percent with investigations realized in skulls of similar ethnic origin and other ethnic groups who present high frequency of interparietal bone. On the contrary, statistically significant differences to 95 percent were found with frequencies determined in caucasian and euroasiatics european skulls. The authors integrated the classificatory tables of Kadanoff and Hanihara-Ishida, to obtain a modified table that allowed to classify all the found variations ...