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Information about Petrous Portion Of The Temporal Bone

Bone: Petrous portion of the temporal bone
Left temporal bone. Outer surface.
Diagrammatic view of the fundus of the right internal acoustic meatus. (Testut.) 1. Crista falciformis. 2. Area facialis, with (2’) internal opening of the facial canal. 3. Ridge separating the area facialis from the area cribrosa superior. 4. Area cribrosa superior, with (4’) openings for nerve filaments. 5. Anterior inferior cribriform area, with (5’) the tractus spiralis foraminosus, and (5’’) the canalis centralis of the cochlea. 6. Ridge separating the tractus spiralis foraminosus from the area cribrosa media. 7. Area cribrosa media, with (7’) orifices for nerves to saccule. 8. Foramen singulare.
Latinpars petrosa ossis temporalis
subject #34 142
Dorlands/Elsevier p_07/12617508
The petrous portion of the temporal bone or pyramid is pyramidal and is wedged in at the base of the skull between the sphenoid and occipital. Directed medialward, forward, and a little upward, it presents for examination a base, an apex, three surfaces, and three angles, and contains, in its interior, the essential parts of the organ of hearing.

Base

The base is fused with the internal surfaces of the squama and mastoid portion.

Apex

The apex, rough and uneven, is received into the angular interval between the posterior border of the great wing of the sphenoid and the basilar part of the occipital; it presents the anterior or internal orifice of the carotid canal, and forms the postero-lateral boundary of the foramen lacerum.

Surfaces

Anterior surface

The anterior surface forms the posterior part of the middle fossa of the base of the skull, and is continuous with the inner surface of the squamous portion, to which it is united by the petrosquamous suture, remains of which are distinct even at a late period of life. It is marked by depressions for the convolutions of the brain, and presents six points for examination:
  1. near the center, an eminence (eminentia arcuata) which indicates the situation of the superior semicircular canal
  2. in front of and a little lateral to this eminence, a depression indicating the position of the tympanic cavity: here the layer of bone which separates the tympanic from the cranial cavity is extremely thin, and is known as the tegmen tympani
  3. a shallow groove, sometimes double, leading lateralward and backward to an oblique opening, the hiatus of the facial canal, for the passage of the greater superficial petrosal nerve and the petrosal branch of the middle meningeal artery
  4. lateral to the hiatus, a smaller opening, occasionally seen, for the passage of the lesser superficial petrosal nerve
  5. near the apex of the bone, the termination of the carotid canal, the wall of which in this situation is deficient in front
  6. above this canal the shallow trigeminal impression for the reception of the semilunar ganglion.

Posterior surface

The posterior surface forms the front part of the posterior fossa of the base of the skull, and is continuous with the inner surface of the mastoid portion.

Near the center is a large orifice, the internal acoustic meatus, the size of which varies considerably; its margins are smooth and rounded, and it leads into a short canal, about 1 cm. in length, which runs lateralward. It transmits the facial and acoustic nerves and the internal auditory branch of the basilar artery.

The lateral end of the canal is closed by a vertical plate, which is divided by a horizontal crest, the crista falciformis, into two unequal portions.

Each portion is further subdivided by a vertical ridge into an anterior and a posterior part.
  • In the portion beneath the crista falciformis are three sets of foramina; these openings together with this central canal transmit the nerves to the cochlea.
  • one group, just below the posterior part of the crest, situated in the area cribrosa media, consists of several small openings for the nerves to the saccule;
  • below and behind this area is the foramen singulare, or opening for the nerve to the posterior semicircular duct;
  • in front of and below the first is the tractus spiralis foraminosus, consisting of a number of small spirally arranged openings, which encircle the canalis centralis cochleæ.
  • The portion above the crista falciformis presents behind, the area cribrosa superior, pierced by a series of small openings, for the passage of the nerves to the utricle and the superior and lateral semicircular ducts, and, in front, the area facians, with one large opening, the commencement of the canal for the facial nerve (aquæductus Fallopii).
Behind the internal acoustic meatus is a small slit almost hidden by a thin plate of bone, leading to a canal, the aquæductus vestibuli, which transmits the ductus endolymphaticus together with a small artery and vein.

Above and between these two openings is an irregular depression which lodges a process of the dura mater and transmits a small vein; in the infant this depression is represented by a large fossa, the subarcuate fossa, which extends backward as a blind tunnel under the superior semicircular canal.
  1. Crista falciformis.
  2. Area facialis, with (2’) internal opening of the facial canal.
  3. Ridge separating the area facialis from the area cribrosa superior.
  4. Area cribrosa superior, with (4’) openings for nerve filaments.
  5. Anterior inferior cribriform area, with (5’) the tractus spiralis foraminosus, and (5’’) the canalis centralis of the cochlea.
  6. Ridge separating the tractus spiralis foraminosus from the area cribrosa media.
  7. Area cribrosa media, with (7’) orifices for nerves to saccule.
  8. Foramen singulare.

Interior surface

The inferior surface is rough and irregular, and forms part of the exterior of the base of the skull. It presents eleven points for examination:
  1. near the apex is a rough surface, quadrilateral in form, which serves partly for the attachment of the Levator veli palatini and the cartilaginous portion of the auditory tube, and partly for connection with the basilar part of the occipital bone through the intervention of some dense fibrous tissue;
  2. behind this is the large circular aperture of the carotid canal, which ascends at first vertically, and then, making a bend, runs horizontally forward and medialward; it transmits into the cranium the internal carotid artery, and the carotid plexus of nerves;
  3. medial to the opening for the carotid canal and close to its posterior border, in front of the jugular fossa, is a triangular depression; at the apex of this is a small opening, the aquæductus cochleæ, which lodges a tubular prolongation of the dura mater establishing a communication between the perilymphatic space and the subarachnoid space, and transmits a vein from the cochlea to join the internal jugular;
  4. behind these openings is a deep depression, the jugular fossa, of variable depth and size in different skulls; it lodges the bulb of the internal jugular vein;
  5. in the bony ridge dividing the carotid canal from the jugular fossa is the small inferior tympanic canaliculus for the passage of the tympanic branch of the glossopharyngeal nerve;
  6. in the lateral part of the jugular fossa is the mastoid canaliculus for the entrance of the auricular branch of the vagus nerve;
  7. behind the jugular fossa is a quadrilateral area, the jugular surface, covered with cartilage in the fresh state, and articulating with the jugular process of the occipital bone;
  8. extending backward from the carotid canal is the vaginal process, a sheath-like plate of bone, which divides behind into two laminæ; the lateral lamina is continuous with the tympanic part of the bone, the medial with the lateral margin of the jugular surface;
  9. between these laminæ is the styloid process, a sharp spine, about 2.5 cm. in length;
  10. between the styloid and mastoid processes is the stylomastoid foramen; it is the termination of the facial canal, and transmits the facial nerve and stylomastoid artery;
  11. situated between the tympanic portion and the mastoid process is the tympanomastoid fissure, for the exit of the auricular branch of the vagus nerve.

Angles

The superior angle, the longest, is grooved for the superior petrosal sinus, and gives attachment to the tentorium cerebelli; at its medial extremity is a notch, in which the trigeminal nerve lies.

The posterior angle is intermediate in length between the superior and the anterior. Its medial half is marked by a sulcus, which forms, with a corresponding sulcus on the occipital bone, the channel for the inferior petrosal sinus. Its lateral half presents an excavation—the jugular fossa—which, with the jugular notch on the occipital, forms the jugular foramen; an eminence occasionally projects from the center of the fossa, and divides the foramen into two.

The anterior angle is divided into two parts—a lateral joined to the squama by a suture (petrosquamous), the remains of which are more or less distinct; a medial, free, which articulates with the spinous process of the sphenoid.

At the angle of junction of the petrous part and the squama are two canals, one above the other, and separated by a thin plate of bone, the septum canalis musculotubarii (processus cochleariformis); both canals lead into the tympanic cavity.
  • The upper one (semicanalis m. tensoris tympani) transmits the Tensor tympani.
  • the lower one (semicanalis tubae auditivae) forms the bony part of the auditory tube.
The tympanic cavity, auditory ossicles, and internal ear, are described with the organ of hearing.

Additional images


Base of skull. Inferior surface.

Base of the skull. Upper surface.

Dissection of the muscles of the palate from behind.




This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained herein may be outdated. Please edit the article if this is the case, and feel free to remove this notice when it is no longer relevant.
Human cranial bones
 •  • [ e]
occipital bone: Foramen magnum | Squama occipitalis (Inion | Nuchal lines | Planum occipitale | Planum nuchale | Internal occipital protuberance | Sagittal sulcus | Internal occipital crest) | Lateral parts (Hypoglossal canal | Condyloid fossa | Condyloid canal | Jugular process | Jugular tubercle) | Basilar part (Pharyngeal tubercle) parietal bone: Parietal eminence | Temporal line | Parietal foramen frontal bone: Squama frontalis (Frontal suture | Frontal eminence | Superciliary arches | Glabella | Supraorbital foramen | Zygomatic process | Sagittal sulcus | Frontal crest | Foramen cecum) | Pars orbitalis (Frontal sinus | Frontonasal duct) temporal bone: Squama temporalis (Articular tubercle | Suprameatal triangle | Mandibular fossa | Petrotympanic fissure) | Mastoid portion (Mastoid foramen | Mastoid process | Mastoid notch | Occipital groove | Sigmoid sulcus | Mastoid antrum) | Petrous portion (Hiatus of the facial canal | Internal auditory meatus | Subarcuate fossa | Carotid canal | Aqueduct of cochlea | Jugular fossa | Inferior tympanic canaliculus | Mastoid canaliculus | Styloid process | Stylomastoid foramen | Jugular foramen | Petrosquamous suture) | Tympanic part (Suprameatal spine) | Zygomatic process sphenoid bone: Sphenoidal sinuses | Ethmoidal spine | Optic foramen | Sella turcica | Fossa hypophyseos | Dorsum sellae | Posterior clinoid processes | Carotid groove | Lingula sphenoidalis | Sphenoidal conchæ | Great wings (Spina angularis | Foramen rotundum | Foramen ovale | Foramen Vesalii | Foramen spinosum | Infratemporal crest | Sulcus tubae auditivae | Small wings | Superior orbital fissure | Anterior clinoid process | Optic foramen) | Pterygoid processes (Pterygoid fossa | Scaphoid fossa | Lateral pterygoid plate | Medial pterygoid plate | Pterygoid hamulus | Sphenoidal conchæ | Sphenoidal sinuses) ethmoid bone: Cribriform plate | Crista galli | Perpendicular plate | Labyrinth | Ethmoid sinus | Uncinate process | Middle nasal concha | Superior meatus | Superior nasal concha | Middle meatus
Facial bones
maxilla: Incisive fossa | Maxillary sinus | Incisive fossa | Canine fossa | Infraorbital foramen | Anterior nasal spine | Alveolar canals | Orbitofrontal cortex | Infraorbital canal | Pterygopalatine canal | Zygomatic process | Agger nasi | Anterior lacrimal crest | Alveolar process | Incisive foramen | Incisive canals | Foramina of Scarpa | Premaxilla | Anterior nasal spine lacrimal bone: Posterior lacrimal crest zygomatic bone: Zygomaticofacial foramen | Zygomaticotemporal foramen | Zygomaticoörbital foramina palatine bone: Pterygopalatine fossa | Pterygoid fossa | Horizontal plate | Posterior nasal spine | Perpendicular plate | Pterygopalatine canal | Sphenopalatine foramen | Pyramidal process | Orbital process | Sphenoidal process mandible: Symphysis menti | Mental foramen | Mylohyoid line | Ramus mandibulae | Mandibular foramen | Mandibular canal others: nasal bone | inferior nasal conchae | vomer bone
composite structures
Cranial sutures: Coronal | Lambdoidal | Occipitomastoid | Parietomastoid | Sphenofrontal | Sphenoparietal |Sphenosquamosal | Sphenozygomatic |Squamosal | Zygomaticotemporal | Zygomaticofrontal | Frontal/Metopic | Sagittal | Frontoethmoidal | Petrosquamous | Sphenoethmoidal | Sphenopetrosal Asterion | Nasion | Pterion | Dacryon | Inferior orbital fissure
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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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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Elsevier, the world's largest publisher of medical and scientific literature, forms part of the Reed Elsevier group. Based in Amsterdam, the company has substantial operations in the UK, USA and elsewhere.
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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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carotid canal, which ascends at first vertically, and then, making a bend, runs horizontally forward and medialward; it transmits into the cranium the internal carotid artery, and the carotid plexus of nerves.

Sympathetics to the head also pass through the carotid canal.
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The trigeminal ganglion (or Gasserian ganglion, or semilunar ganglion) is a sensory ganglion of the trigeminal nerve which occupies a cavity (Meckel's cave) in the dura mater covering the trigeminal impression near the apex of the petrous part of the temporal bone.
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The internal acoustic meatus (also internal auditory meatus) is a canal in the temporal bone of the skull that carries nerves from inside the cranium towards the middle and inner ear compartments.
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In human anatomy, the basilar artery is one of the arteries that supplies the brain with oxygen-rich blood.

Course

It arises from the confluence of the two vertebral arteries at the junction between the medulla oblongata and the pons.
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The introduction to this article provides insufficient context for those unfamiliar with the subject matter.
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foramen singulare, or opening for the nerve to the posterior semicircular duct.

This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained herein may be outdated.
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The semicircular canals are three half-circular, interconnected tubes located inside each ear that are the equivalent of three gyroscopes located in three orthogonal planes.
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Utricle ("pouch") can refer to:
  • Utricle (ear)
  • Prostatic utricle
  • a fruit type, similar to achene, found in beet and dock

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subarcuate fossa, which extends backward as a blind tunnel under the superior semicircular canal.

External links

  • Roche Lexicon - illustrated navigator, at Elsevier 34257.

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The introduction to this article provides insufficient context for those unfamiliar with the subject matter.
Please help [ improve the introduction] to meet Wikipedia's layout standards.

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The levator veli palatini is a muscle of the human body. During swallowing, it contracts, elevating the soft palate to help prevent food from entering the nasopharynx. It is innervated via the pharyngeal plexus, primarily by the vagus nerve (CN X).
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The Eustachian tube (or auditory tube) is a tube that links the pharynx to the middle ear. In adults the Eustachian tube is approximately 35 mm long. It is named after the 16th century anatomist Eustachius.
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The jugular fossa is a deep depression in the inferior part of the base of the skull. More specifically, it is located in the temporal bone, behind the openings for the carotid canal and the aquæductus cochleæ.
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For the anatomy term, see Subarachnoid space.


SubArachnoid Space is a San Francisco-based psychedelic rock band founded in 1996 by Mason Jones, the owner of the independent music label Charnel Music.
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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 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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In anatomy, a styloid process (from Greek stylos, "pillar"), usually serving as points of attachment for muscles, refers to the slender, pointed process (protrusion) of :
  • temporal bone of the skull - Styloid process (temporal)

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stylomastoid foramen

It is the termination of the facial canal, and transmits the facial nerve and stylomastoid artery.

Clinical Relevance

Bell's palsy can result from inflammation of the facial nerve where it leaves the skull at the stylomastoid foramen.
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The facial canal is a canal running from the internal acoustic meatus to the stylomastoid foramen. It is also referred to as the aqueduct of Fallopius.

See also

  • facial nerve
  • prominence of the facial canal
  • hiatus of the facial canal


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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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The superior petrosal sinus, within the human head, is an area beneath the brain, which allows blood veins to span the area, from the center of the head downward. It drains from the cavernous sinus (beneath the brain) to the transverse sinuses, which lead further to the internal
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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 trigeminal nerve (the fifth cranial nerve, also called the fifth nerve or simply V) is responsible for sensation in the face. It is similar to the spinal nerves C2–S5, which are responsible for sensation in the rest of the body.
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Public domain comprises the body of knowledge and innovation (especially creative works such as writing, art, music, and inventions) in relation to which no person or other legal entity can establish or maintain proprietary interests within a particular legal jurisdiction.
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Henry Gray's Anatomy of the Human Body (or Gray's Anatomy as it has commonly been shortened) is an English-language human anatomy textbook widely regarded as a classic work on the subject.
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skull is normally made up of 22 bones. Except for the mandible, all of the bones of the skull are joined together by sutures, synarthrodial (immovable) joints formed by bony ossification, with Sharpey's fibres permitting some flexibility.
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