Pathology Predominate, internal auditory canal Extension to CPA Compression on brainstem and brain hydrops Anterior trigeminal nerver Medial: abducent nerve Inferior:ⅨXXI,XIPathology ◼ Predominate: internal auditory canal ◼ Extension to CPA ◼ Compression on brainstem and brain hydrops ◼ Anterior: trigeminal nerve, ◼ Medial: abducent nerve ◼ Inferior: IX, X, XI, XII