Internal auditory meatus

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Bone: Internal auditory meatus
Left temporal bone. Inner surface.
Diagrammatic view of the fundus of the right internal acoustic meatus.
Latin	meatus acusticus internus
Gray's	subject #34 143
Dorlands / Elsevier	m_06/12518154

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.

Structure

The opening to the internal acoustic meatus is located inside the cranial cavity, near the center of the posterior surface of the temporal bone. The size varies considerably; its margins are smooth and rounded. The canal is short (about 1 cm) and runs laterally into the bone. At its end are the openings for three different canals, one of which is the facial canal.

Unlike the external acoustic meatus, the internal acoustic meatus does not transmit sound. It instead transmits the facial and vestibulocochlear nerves and the labyrinthine artery (an internal auditory branch of the basilar artery). The facial nerve travels through the facial canal, eventually exiting the skull at the stylomastoid foramen.

The opening of the meatus is called the porus acusticus internus, or its English translation, the internal acoustic opening.

Additional images

Temporal bone at birth. Inner aspect.

Base of the skull. Upper surface.

Horizontal section through left ear; upper half of section.

The cochlea and vestibule, viewed from above.

See also

• External auditory meatus

References

• p_30/12660414 at Dorland's Medical Dictionary

External links

• SUNY Figs 30:01-08
• Norman/Georgetown cranialnerves (VII)
• Diagram of Porus acusticus internus
• Diagram of Porus acusticus internus

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 As such, some of the information contained herein may be outdated.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. Template:Skull

v • d • e Foramina of the skull (and canals, fissures, meati, and hiati)
Anterior cranial fossa	to Orbit: ethmoidal foramina (anterior, posterior) to Nasal cavity: olfactory foramina (CN-I) - foramen cecum
Middle cranial fossa	to Orbit: optic canal (CN-II) - superior orbital fissure (CN-III,IV,V1,VI) to Pterygopalatine fossa: foramen rotundum (CN-V2) - pterygoid canal to Infratemporal fossa: foramen ovale (CN-V3) - foramen spinosum/carotid canal other: foramen lacerum - hiatus for greater petrosal nerve - hiatus for lesser petrosal nerve - sphenoidal emissary foramen
Posterior cranial fossa	internal auditory meatus/facial canal/stylomastoid foramen (CN-VII,VIII) - jugular foramen (CN-IX,X,XI) - foramen magnum (CN-XI) - hypoglossal canal (CN-XII) - condylar canal - mastoid foramen
Orbit	to Nasal cavity: nasolacrimal canal to Face: supraorbital (notch, foramen) - infraorbital (foramen, groove) - zygomatic foramen (-facial, -temporal) to Pterygopalatine fossa: inferior orbital fissure
Pterygopalatine fossa	to Nasal cavity: sphenopalatine foramen to Oral cavity: greater palatine canal/greater palatine foramen - lesser palatine canals/lesser palatine foramina to Infratemporal fossa: pterygomaxillary fissure to Nasopharynx: palatovaginal canal
Nasal cavity	to Oral cavity: incisive canals - incisive foramen
Other	external acoustic meatus - mandibular foramen - mental foramen - parietal foramen - petrotympanic fissure - semilunar hiatus

Acknowledgement and Attribution Regarding Sources of Content

Some of the initial content on this page may be incorporated in part from copyleft sources in the public domain including wikis such as Wikipedia and AskDrWiki. Drug information for patients came from the The National Library of Medicine. Infectious disease information may have come from the Centers for Disease Control (CDC). Differential Diagnoses are drawn from clinicians as well as an amalgamation of 3 sources: 1.The Disease Database; 2. Kahan, Scott, Smith, Ellen G. In A Page: Signs and Symptoms. Malden, Massachusetts: Blackwell Publishing, 2004:3; 3. Sailer, Christian, Wasner, Susanne. Differential Diagnosis Pocket. Hermosa Beach, CA: Borm Bruckmeir Publishing LLC, 2002:7 .