posterior cranial fossa


pos·te·ri·or cra·ni·al fos·sa

[TA] the internal base of the skull posterior to the crest of the petrous part of the temporal bones and the dorsum sellae and anterior to the grooves for the transverse sinuses, where the cerebellum, pons, and medulla oblongata rest. Synonym(s): fossa cranii posterior [TA]

posterior cranial fossa

The posteriormost of the three divisions of the internal cranial base, which houses the inferior face of the cerebellum posteriorly and the pons and medulla oblongata anteriorly. The floor of the fossa is the largest and deepest depression of the inner surface of the base of the brain, and is covered by dura mater. The posterior cranial fossa is bounded anteriorly by the dorsum sellae of the sphenoid bone; laterally by the superior margin of the petrous part of the temporal bone and the mastoid angle of the parietal bone; and posteriorly by the squamous part of the occipital bone below the transverse sinuses.

posterior cranial fossa

The posterior third of the floor of the cranial cavity; it is larger and deeper than the anterior and middle cranial fossae. The posterior cranial fossa is formed from the posterior surface of the body of the sphenoid bone (the dorsum sella), the posterior surfaces of the petrous and mastoid portions of the temporal bones, and the inner surfaces of the occipital bones. The posterior cranial fossa contains the internal auditory canals, the foramen magnum, and the jugular foramina. The brainstem, the cerebellum, and the transverse and sigmoid sinuses lie in the posterior cranial fossa. See also: fossa