Petrous bone meningioma classification
Bricolo et al. 1) divided posterior petrous bone meningiomas into tumors anterior to the IAC and tumors posterior to the IAC. D
Desgeorges et al. refined this description when they introduced the A-M-P classification:
Petrous bone meningiomas were classified into 3 types following the Desgeorges classification, 2) which is based on the tumor's dural attachment to the posterior petrous bone surface:
Type A (anterior) meningiomas originate from the petrous apex. see petrous apex meningioma.
Type M (middle) meningiomas originate at the level of the internal auditory canal (IAC)
Type P (posterior) meningiomas develop from the posterior part of the petrous bone, between the posterior wall of the IAC and the groove of the sigmoid sinus.