The posterior cranial fossa is part of the intracranial cavity, located between the foramen magnum and tentorium cerebelli. It contains the brainstem and cerebellum and houses part of the medulla.
Anteriorly it extends to the apex of the petrous temporal bone.
Laterally portions of the squamous temporal and mastoid part of the temporal bone form its walls.
Posteriorly it is enclosed by the occipital bone. laterally portions of the squamous temporal and mastoid part of the temporal bone form its walls.
The region in the upper anterior third of the posterior fossa is a surgically hidden, narrow corridor between the petroclival surface anteriorly and the surface of the brainstem posteriorly.
Posterior fossa circulation
Veins in the posterior fossa
The veins are located on the surface of the cerebellar hemispheres, and generally drain into the adjacent sigmoid sinus and transverse sinus, with the exception of the vermian veins.
The course of the vein, and its point of connection with the sinus help idenify the sufrace it is running along. For example, the veins coming up from below the transverse sinus and entering the more proximal (with respect to the torcula) aspect of the sinus must be located on the mesial posterior surface, whereas a similar vein below the transverse sinus and draining into its distal aspect has to be located on the lateral aspect of the inferior surface.
Veins draining into the superior petrosal sinus or inferior petrosal sinus must, at some point, run on the anterior surface, since the petrosal sinus is located anterior to the cerebellum.
In the midline, along the vermis, run the superior vermian vein and inferior vermian vein.
Posterior Fossa Nerves