Morphology of asterion and its proximity to deep vein sinuses in Iranian adult skull.

The asterion is located at the posterior lateral side of the skull at the junction of the parietal, temporal and occipital bones. We examined the morphology of the asterion, its association with deep vein elements, the mastoid apex and inion in 105 adult cadavas (210 hemicraniums) including 146 males and 64 females at the anatomy lab of the Legal Medicine Organization. Two types of asterion were observed. Type I was found in 14.7%, and type II in 85.3% of cases. In 70% of cases, the asterion was at or above the venous sinus. The distance between the asterion and the mastoid appendage on the right side was 47.03 mm and on the left side was 46.5 mm. The distance between the asterion and the inion at the right side was 70.55 mm and on the left side was 70.2 mm. The asterion in 70% of cases was at or above the level of the transverse sinus. For this reason, in posterior fossa surgical approaches, the first burr hole is preferred to start in the lower parts of the asterion.