Petrous apex

Dr Craig Hacking et al.

The petrous apex is the pyramid-shaped anteromedial part of the petrous part of the temporal bone. It is oriented obliquely in the skull base and articulates with the posterior aspect of the greater wing of the sphenoid and occipital bones.

The lateral boundary is the inner ear, medially the petro-occipital fissure, anteriorly the petrosphenoidal fissure and petrous part of the internal carotid artery in the carotid canal and posteriorly the posterior cranial fossa. Superiorly is the middle cranial fossa, Meckel cave and petrous ICA. Inferiorly is the jugular bulb and inferior petrosal sinus.

The internal auditory canal divides it into a larger anterior portion, containing bone marrow that may be pneumatized and a smaller posterior portion, derived from the otic capsule.

Related pathology

See also

Anatomy: Head and neck
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Article information

rID: 66916
System: Head & Neck
Section: Anatomy
Synonyms or Alternate Spellings:

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Cases and figures

  • Figure 1: temporal bone divisions: annotated CT
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