Petrooccipital fissure

The petrooccipital fissure is situated on both sides of the grooved surface of the basilar part of the occipital bone, separating it from the petrous portion of the temporal bone. Inside the posterior cranial fossa, the petrooccipital fissure can be found anterolateral to the foramen magnum. It extends laterally to open into the jugular foramen. The fissure designates the position of the inferior petrosal sinus, which serves as a connection between the sigmoid sinus and the cavernous venous sinus.

The petrooccipital fissure provides a physical space of significance for transcranial approaches to the cranial base during surgical approaches.