The Surface and Intracranial Location of Asterion

Asterion is identified as the connection point of sutura parietomastoidea, sutura occipitomastoidea, and sutura lambdoidea. The location of asterion, which is primarily preferred as a landmark during posterolateral surgical approach for intracranial operations, shows many variables. The aim of this study was to identify the surface location of the asterion and determine the distances between intracranial anatomical structures and asterion.

At this present study, 11 hemicraniums (22 asterion points), situated at the laboratory of Department of Anatomy, Faculty of Medicine, Bursa Uludag University, were used. The asterion points which the sesamoid bone located were classified as type I and the ones which sesamoid bone did not locate were classified as type II. According to the proximity of asterion with sinus transversus, 3 groups were classified. About 19 parameters were measured related to asterion. The obtained data were analyzed in SPSS 22.

As a result of findings, while sesamoid bone was seen at 7 asterion points (type I), at 15 points sesamoid bone was not detected (type II) (respectively, 31.81%, 68.19%). It was identified that 15 asterion points were at the surface, 5 ones were average 3.42 ± 2.52 mm over, 2 ones average 3.21 ± 2.26 mm below of the projection of sinus transversus. Statistically significance was not seen between the measurements taken from left and right sides.

Asterion is an important landmark for the retrosigmoid approaches. The surface and intracranial location of the asterion and proximity with dural sinuses are important for surgeons not to cause fatal subdural hematomas during the approaches using "Burr Hole" technic in neurochirurgie operations.