The asterion is the junction point on the posterior lateral skull where the lambdoid suture (between parietal and occipital bones), the parietomastoid suture (between parietal and mastoid temporal bone), and the occipitomastoid suture meet. It lies approximately 4 cm behind and 1 cm above the tip of the mastoid process. Beneath the asterion, the transverse sinus transitions into the sigmoid sinus in the majority of individuals.
The asterion is the landmark for the standard retrosigmoid craniotomy for posterior fossa tumour removal (vestibular schwannoma, meningioma, epidermoid), microvascular decompression for trigeminal neuralgia, and retrosigmoid approaches to the petroclival region. The initial burr hole of the craniotomy is placed at or just medial to the asterion to avoid inadvertent entry into the transverse or sigmoid sinus. The relationship of the asterion to the underlying sinus varies and should be confirmed by preoperative imaging.
Initial burr hole placement directly over the asterion risks entering the underlying transverse-sigmoid sinus junction, causing venous haemorrhage that is controlled by bipolar coagulation, Gelfoam packing, or direct suture of the dural sinus; pre-operative MRV identifies the exact sinus position to guide safe burr hole siting.
This website uses cookies to enhance your experience. Some are essential for site functionality, while others help us analyze and improve your usage experience. Please review your options and make your choice.
If you are under 16 years old, please ensure that you have received consent from your parent or guardian for any non-essential cookies.
Your privacy is important to us. You can adjust your cookie settings at any time. For more information about how we use data, please read our privacy policy. You may change your preferences at any time by clicking on the settings button below.
Note that if you choose to disable some types of cookies, it may impact your experience of the site and the services we are able to offer.
Some required resources have been blocked, which can affect third-party services and may cause the site to not function properly.
This website uses cookies to enhance your browsing experience and ensure the site functions properly. By continuing to use this site, you acknowledge and accept our use of cookies.
