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Information about Posterior Cranial Fossa

Base of the skull. Upper surface.
Latinfossa cranii posterior
subject #47 192
MeSH Cranial+Fossa,+Posterior
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 (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

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Bones of head and neck: cranial sutures, fontanelles, and related regions
Cranial suturesCoronal - Lambdoid - Occipitomastoid - Sphenofrontal - Sphenoparietal - Sphenosquamosal - Sphenozygomatic -Squamosal - Zygomaticotemporal - Zygomaticofrontal - Frontal/Metopic - Sagittal - Frontoethmoidal - Petrosquamous - Sphenoethmoidal - Sphenopetrosal
FontanellesAnterior fontanelle - Posterior fontanelle
Foramina of multiple bonesInferior orbital fissure - Foramen lacerum - Jugular foramen - Nasolacrimal canal
FossaeAnterior cranial fossa - Middle cranial fossa - Posterior cranial fossa - Cranial cavity
Other compound structuresAsterion - Nasion - Pterion - Dacryon - Zygomatic arch - Calvaria - Temporal fossa - Infratemporal fossa - Stephanion - Pterygomaxillary fissure - Pterygopalatine fossa
Latin}}} 
Official status
Official language of: Vatican City
Used for official purposes, but not spoken in everyday speech
Regulated by: Opus Fundatum Latinitas
Roman Catholic Church
Language codes
ISO 639-1: la
ISO 639-2: lat
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Medical Subject Headings (MeSH) is a huge controlled vocabulary (or metadata system) for the purpose of indexing journal articles and books in the life sciences. Created and updated by the United States National Library of Medicine (NLM), it is used by the MEDLINE/PubMed
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The cranial cavity, or intracranial space, is the space formed inside the skull. The brain occupies the cranial cavity, which is lined by the meninges and which contains fluid to cushion blows.
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In anatomy, in the occipital bone, the foramen magnum (Latin: 'great hole') is one of the several oval or circular apertures in the base of the skull (the foramina), through which the medulla oblongata (an extension of the spinal cord) enters and exits the skull vault.
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The tentorium cerebelli or cerebellar tentorium (Latin: "tent of the cerebellum") is an extension of the dura mater that separates the cerebellum from the inferior portion of the occipital lobes.
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The brain stem is the lower part of the brain, adjoining and structurally continuous with the spinal cord. Most sources consider the pons, medulla oblongata, and midbrain all to be part of the brainstem.
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The cerebellum (Latin: "little brain") is a region of the brain that plays an important role in the integration of sensory perception and motor output. Many neural pathways link the cerebellum with the motor cortex—which sends information to the muscles causing them
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In anatomy, in the occipital bone, the foramen magnum (Latin: 'great hole') is one of the several oval or circular apertures in the base of the skull (the foramina), through which the medulla oblongata (an extension of the spinal cord) enters and exits the skull vault.
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In anatomy, the accessory nerve is a nerve that controls specific muscles of the neck. As a part of it is traditionally believed to originate in the brain, it is considered a cranial nerve.
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The vestibulocochlear nerve (also known as the auditory or acoustic nerve) is the eighth of twelve cranial nerves, and is responsible for transmitting sound and equilibrium (balance) information from the inner ear to the brain.
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Cranial nerves are nerves that emerge directly from the brain in contrast to spinal nerves which emerge from segments of the spinal cord. Although thirteen cranial nerves in humans fit this description, twelve are conventionally recognized.
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The temporal bones are situated at the sides and base of the skull.

The temporal bone supports that part of the face known as the temple.

Parts

Each consists of five parts:
  • Squama temporalis
  • Mastoid portion
  • Petrous portion
  • Tympanic part

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The occipital bone, a saucer-shaped membrane bone situated at the back and lower part of the cranium, is trapezoid in shape and curved on itself. It is pierced by a large oval aperture, the foramen magnum, through which the cranial cavity communicates with the vertebral canal.
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The internal jugular vein collects the blood from the brain, from the superficial parts of the face, and from the neck.

Path

It is directly continuous with the sigmoid sinus, and begins in the posterior compartment of the jugular foramen, at the base of the skull.
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The glossopharyngeal nerve is the ninth of twelve pairs of cranial nerves. It exits the brainstem out from the sides of the upper medulla, just rostral (closer to the nose) to the vagus nerve.
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The vagus nerve (also called pneumogastric nerve or cranial nerve X) is the tenth of twelve paired cranial nerves, and is the only nerve that starts in the brainstem (within the medulla oblongata) and extends, through the jugular foramen, down below the head, to the
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In anatomy, the accessory nerve is a nerve that controls specific muscles of the neck. As a part of it is traditionally believed to originate in the brain, it is considered a cranial nerve.
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The internal jugular vein collects the blood from the brain, from the superficial parts of the face, and from the neck.

Path

It is directly continuous with the sigmoid sinus, and begins in the posterior compartment of the jugular foramen, at the base of the skull.
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The sigmoid sinuses (left & right), within a human head, are 2 areas beneath the brain, which allow blood veins to span the area, from the center of the head downward. They drain from the transverse sinuses (under the back of the brain) to the internal jugular vein.
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The jugular foramen, a large aperture aperture in the - [[Lambdoid suture|Lambdoid]] - [[Occipitomastoid suture|Occipitomastoid]] - [[Sphenofrontal suture|Sphenofrontal]] - [[Sphenoparietal suture|Sphenoparietal]] - [[Sphenosquamosal suture|Sphenosquamosal]] - [[Sphenozygomatic
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The State University of New York Health Science Center at Brooklyn, better known as SUNY Downstate Medical Center, is an academic medical center and is the only one of its kind in the Borough of Brooklyn in New York City.
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Bones are rigid organs that form part of the endoskeleton of vertebrates. They function to move, support, and protect the various organs of the body, produce red and white blood cells and store minerals.
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Head and neck anatomy focuses on the structures of the head and neck of the human body, including the brain, bones, muscles, blood vessels, nerves, glands, nose, mouth, teeth, tongue, and throat.
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Cranial sutures are the joints between the bones of the skull (or "cranium"), bound together by Sharpey's fibres. A tiny amount of movement is permitted at sutures, which contributes to the compliance and elasticity of the skull.
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fontanelle (or fontanel) is one of two "soft spots" on a newborn human's skull. There are, however, two more fontanelles of interest, the mastoid fontanelle, and the sphenoidal fontanelle.
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Cranial sutures are the joints between the bones of the skull (or "cranium"), bound together by Sharpey's fibres. A tiny amount of movement is permitted at sutures, which contributes to the compliance and elasticity of the skull.
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The coronal suture is a dense, fibrous connective tissue joint that separates the frontal and parietal bones of the skull. At birth, the bones of the skull do not meet.

Pathology

If certain bones of the skull grow too fast then "premature closure" of the sutures may occur.
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The lambdoid suture (or Lambdoidal suture) is a dense, fibrous connective tissue joint that separates the parietal and temporal bones of the skull from the occipital bone.

Its name comes from the lambda-like shape this suture makes on the back of the skull.
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The occipitomastoid suture is the cranial suture between the occipital bone and the mastoid portion of the temporal bone.

It is continuous with the lambdoidal suture.
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The Sphenofrontal suture is the cranial suture between the sphenoid bone and the frontal bone.

Additional images



The skull from the front.

Base of the skull. Upper surface.

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