anterior: horizontal part of ICA posterior: posterior bony labyrinth medial: IAC, petrous apex inferior: basal turn of the cochlea
Class II: infralabyrinthine
迷路下型
hypotympanic and infralabyrinthine cells
anterior: ICA vertical part, petrous apex, clivus posterior: dura of the posterior cranial fossa and sigmoid sinus medial: IAC, lower clivus, occipital condyle inferior: jugular bulb, lower cranial nerves
Class III: infralabyrinthine-apical
迷路下-岩尖型
infralabyrinthine compartment, ICA reaching up to petrous apex
anterior: ICA vertical 8 horizontal parts posterior: posterior fossa through the retrofacial air cells medial: petrous apex, clivus, sphenoid sinus, rhinopharynx inferior: jugular bulb, lower cranial nerves
Class IV: massive labyrinthine
广泛型
entire otic capsule
anterior: ICA vertical 8 horizontal parts posterior: posterior fossa dura and IAC medial: petrous apex, superior and mid clivus, sphenoid sinus inferior: infralabyrinthine compartment
Class V: apical
岩尖型
petrous apex
anterior: Meckel’s cave area and may involve the V nerve posterior: IAC and posterior cranial fossa medial: superior or mid clivus, sphenoid sinus inferior: infralabyrinthine compartment
亚型
Subclass
Features
Clivus (C) 斜坡亚型
superior and mid clival extensions are seen from massive, infralabyrinthine-apical and apical PBC whereas the lower clival involvement is a feature of infralabyrinthine-apical PBC
Sphenoid sinus (S) 蝶窦亚型
sphenoid sinus involvement is seen from anteromedial extensions of massive, infralabyrinthine-apical and apical PBC; it is a rare extension
Rhinopharynx (R) 鼻咽亚型
it is the rarest extension of the PBC; it is an extension of infralabyrinthine-apical or massive PBC,which may extend through the clivus beneath the sphenoid sinus into the rhinopharynx