Posterior cranial fossa
1927395
206462706
2008-04-18T10:24:06Z
194.83.138.187
Made caption on image more clear to indicate where it is!
{{Infobox Anatomy |
Name = {{PAGENAME}} |
Latin = fossa cranii posterior |
GraySubject = 47 |
GrayPage = 192 |
Image = Gray193.png |
Caption = Base of the skull. Upper surface. The Posterior cranial fossa is labeled a third of the way up the image from the bottom |
System = |
MeshName = Cranial+Fossa,+Posterior |
MeshNumber = A01.456.830.200 |
}}
The '''posterior cranial fossa''' is part of the [[intracranial cavity]], located between the [[foramen magnum]] and [[tentorium cerebelli]]. It contains the [[brainstem]] and [[cerebellum]].
This is the most inferior of the fossae. It houses the cerebellum, medulla and pons.
Anteriorly it extends to the apex of the petrous temporal. Posteriorly it is enclosed by the
occipital bone. Laterally portions of the squamous temporal and mastoid part of the
temporal bone form its walls.
== Features ==
===Foramen magnum===
: ''See main article at [[Foramen magnum]]''
The most conspicuous, large opening in the floor of the fossa. It transmits the
medulla, the ascending portions of the [[spinal accessory nerve]] (XI), and the vertebral
arteries.
===Internal acoustic meatus===
Lies in the anterior wall of the posterior cranial fossa. It transmits the facial (VII) and [[vestibulocochlear]] (VIII) [[cranial nerves]] into canal in the [[petrous temporal bone]].
===Jugular foramen===
Lies between the inferior edge of the petrous temporal bone and the adjacent
[[occipital bone]] and transmits the [[internal jugular vein]] (actually begins here), the
[[glossopharyngeal]] (IX), the [[vagus]] (X) and the [[accessory nerve|accessory]] (XI) nerves.
===Anterior condylar (hypoglossal) canal===
Lies at the anterolateral margins of the f. magnum and transmits the hypoglossal
(XII) nerve.
===Other===
Also visible in the posterior cranial fossa are depressions caused by the venous
sinuses returning blood from the brain to the venous circulation:
Right and left transverse sinuses which meet at the confluence of sinuses (marked
by the internal occipital protuberance).
The transverse sinuses pass horizontally from the most posterior point of the occiput.
Where the apex of the petrous temporal meets the squamous temporal, the transverse sinuses lead into sigmoid (S-shaped) sinuses (one on each side).
These pass along the articulation between the posterior edge of the petrous
temporal and the anterior edge of the occipital bones to the jugular foramen where the
sigmoid sinus becomes the [[internal jugular vein]].
Note that a superior petrosal sinus enters the junction of the transverse and sigmoid sinuses.
Also an inferior petrosal sinus enters the [[sigmoid sinus]] near the [[jugular foramen]].
==External links==
* {{SUNYAnatomyLabs|22|os|08|03}}
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{{Sutures}}
{{Foramina of skull}}
[[de:Fossa cranii posterior]]
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