Petrous

Petrous refers to the dense part of the Temporal bone that forms a protective casing for the inner ear. The term "petrous" is derived from the Latin word "petrosus," meaning "rocky," which describes the bone's hard, dense nature.

Anatomy

The petrous portion of the temporal bone is pyramid-shaped and is wedged in at the base of the skull between the sphenoid and occipital bones. It is directed medially, forward, and a little upward. It presents for examination a base, an apex, three surfaces, and three angles, and houses the structures of the inner ear.

Base

The base is fused with the internal surface of the temporal bone and has an opening for the carotid canal and the jugular foramen.

Apex

The apex is pointed and is directed toward the sphenoidal sinus.

Surfaces

The anterior surface forms the posterior part of the middle cranial fossa and contains the foramen lacerum and the hiatus of the facial canal.

The posterior surface forms the anterior part of the posterior cranial fossa and contains the internal acoustic meatus.

The inferior surface forms the roof of the jugular foramen.

Angles

The superior angle is broad and is received into the angular interval between the parietal and the greater wing of the sphenoid.

The inferior angle is fused with the basilar part of the occipital bone.

The anterior angle is extensive and is fused with the greater wing of the sphenoid.

Clinical significance

Due to its location and the vital structures it houses, the petrous part of the temporal bone is of significant clinical importance. Conditions such as petrous apicitis, which is an infection of the petrous apex, can lead to serious complications if not treated promptly. Other conditions that can affect the petrous part of the temporal bone include cholesteatoma, otitis media, and temporal bone fractures.

See also

• Temporal bone
• Inner ear
• Skull

References

Petrous Resources
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