Superior petrosal sinus

At a glance

English

Superior petrosal sinus

Latin (TA2)

Sinus petrosus superior

System

Vein

Region

Head

Side

Paired, left and right

About the superior petrosal sinus

This sinus is a small venous channel within the dura mater at the boundary between the middle and posterior cranial fossae. It is enclosed in the tentorium cerebelli where that sheet is fixed to the upper border of the petrous temporal bone, and it lies in a shallow furrow, the superior petrosal groove, that it has worn into the bone. There is one on each side.

It starts at the back of the cavernous sinus, near the apex of the petrous bone, and passes backwards and laterally along the ridge. Close to the base of the petrous bone it opens into the transverse sinus, just where that sinus curves down to become the sigmoid sinus. On its way it crosses above the trigeminal nerve as that nerve passes forwards to the trigeminal cave.

The sinus collects the superior petrosal veins, which drain the front of the cerebellum and the brainstem and are the main veins seen in surgery at the cerebellopontine angle. It also receives some cerebellar and inferior cerebral veins and small veins from the tympanic cavity of the middle ear. Together with the inferior petrosal sinus it provides a second route for blood to leave the cavernous sinus.

Clinically, the sinus can be the site of a dural arteriovenous fistula or malformation, an abnormal connection between dural arteries and the sinus. These rarely close on their own and are treated by endovascular means or by open surgery. Surgeons operating on acoustic neuromas or on the trigeminal nerve for neuralgia must also deal with the superior petrosal veins and sinus, which can bleed when stretched.

Course and drainage

Begins at

Arises from the posterior part of the cavernous sinus near the petrous apex.

Drains into

Opens into the transverse sinus near the base of the petrous temporal bone, where it turns into the sigmoid sinus.

Drains

Drains the superior petrosal veins, parts of the cerebellum and brainstem, some inferior cerebral veins and the tympanic cavity, and links the cavernous and transverse sinuses.