Sigmoid sinus

The sigmoid sinus is one of the venous sinuses of the brain ( sinus of the dura mater ) and the Hauptabflussweg of brain venous blood. It is the continuation of the transverse sinus and runs an S-shape on the floor of the posterior fossa. The blood outflow occurs at the jugular foramen into the internal jugular vein.

The lamella of bone between the sigmoid sinus and the tympanic cavity is extremely thin, which is why Mittelohrvereiterungen break into the sinus and can cause a venous sinus thrombosis.