Anatomic Position of the Asterion and Implication for Neurosurgical Procedure

Abstract

The asterion is the joining of the lambdoid, parietomastoid, and occipitomastoid sutures. It is classified into two types, type I shows small bones or woven bones, while in type II, woven bones are non-existent. In this study, forty cadavers were conducted and observed the asterion on both sides of skulls showing the approximate ratio of type II and type I was 3:2. The asterion was located by measuring the distances from the asterion to skull landmarks, including inion, the root of zygoma, and mastoid tip. The mean distance between asterion and inion was 62.9 ± 6.0 mm. The mean distance between asterion and the root of zygomatic arch was 58.3 ± 6.1 mm, whereas the mean distance between asterion and mastoid tip was 51.1 ± 5.3 mm. The most common location related to the asterion was the dural venous sinuses on 65 % of tested sides, followed by infratentorial dura and supratentorial dura (25 % and 10 %, respectively). However, the authors found no differences between sexes, sides, and types in any underlying structures.

The driving forces of cranial extra-axial space morphology: age, sex, and drugs

“…The relationship between ectocranial asterion and the transverse/sigmoid sinus has since been explored independently in several populations using similar methods. Results have found the two structures to be directly overlapping in as low as 60% of individuals or as high as 91% (Mwachaka et al, 2009;Wirakiat et al, 2021).…”