Posterior cranial fossa
The posterior fossa (lat., "Posterior fossa"), in animals fossa caudalis referred to is of the skull bone occipital bone ( occiput Os ), temporal bone ( temporal bone ) and sphenoid ( sphenoid ) is formed. In the center lies the foramen magnum (occipital opening), through which the medulla oblongata, which merges into the spinal cord , leaves the interior of the skull. The cerebellar hemispheres form a pit ( fossa cerebellaris ) on either side of the occipital opening . Between these lies a dorsally ascending ridge of bone ( Crista occipitalis interna ), which ends in a distinct bone protrusion ( Protuberantia occipitalis interna ). This protrusion is a crossover point of bone grooves in which important venous blood conductors lie. The so-called cerebral sickle ( falx cerebri ) and the cerebellar tent ( tentorium cerebelli ), which also consists of hard meninges ( dura mater ), are fixed to the bony ridges that extend from the internal occipital protuberance . The anterior border of the posterior fossa forms the temporal bone pyramid ( pars petrosa ossis temporalis ) on both sides , as well as the clivus located between the pyramidal tips , which is formed by parts of the occiput and the sphenoid bone and on which the brain parts bridge and medulla oblongata rest.
Skull penetrations
| Entry point | content |
| Foramen magnum | Medulla oblongata |
| Jugular foramen | Inferior petrosal sinus |
| Porus acousticus internus | Facial nerve |
| Canalis nervi hypoglossi | Hypoglossal nerve |
| Canaliculus tympanicus | Tympanic nerve |
| Canaliculus mastoideus | Auricular branch of the vagus nerve |
| Caroticotympanic canaliculi | Nervi caroticotympanici ( sympathetic ) |
| Apertura canaliculi vestibuli | Endolymphatic sac |