Internal auditory meatus

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 As such, some of the information contained herein may be outdated.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