Superior petrosal sinus
In the combined supra and infratentorial presigmoid approach a temporooccipital craniotomy is performed and the transverse sinus, the superior petrosal sinus and the sigmoid sinus are exposed. C: cerebellum; JB: jugular bulb; SPS: superior petrosal sinus; SS: sigmoid sinus; TL: temporal lobe; TS: transverse sinus.
The superior petrosal sinus receives blood from the cavernous sinus and passes backward and laterally to drain into the transverse sinus.
The sinus runs in the attached margin of the tentorium cerebelli, in a groove in the petrous part of the temporal bone formed by the sinus itself - the superior petrosal sulcus.
The sinus receives some cerebellar and inferior cerebral veins, and veins from the tympanic cavity.
The suprameatal extension of the retrosigmoid approach will permit removal of some tumors that are located mainly in the posterior fossa but that extend into the middle fossa in the region of Meckel's cave. The exposure can be increased by opening the superior petrosal sinus as it crosses in the upper margin of the porus of Meckel's cave and by opening the tentorium lateral to Meckel's cave 1).