Posterior cranial fossa

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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

Skull base, posterior cranial fossa (green)
Entry point content
Foramen magnum Medulla oblongata

Vertebral artery

Anterior spinal artery

Posterior spinal artery

Jugular foramen Inferior petrosal sinus

Glossopharyngeal nerve

Vagus nerve

Accessory nerve

Ascending pharyngeal artery

Internal jugular vein

Porus acousticus internus Facial nerve

Vestibulocochlear nerve

Labyrinthine artery

Vena labyrinthi

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

See also