85% of CP angle mass
90% from inferior division (superior division 6%) of vestibular nerve, within or near vestibular (Scarpa) ganglion, at porus acousticus, or just within IAC (near Obersteiner-Redlich zone = transition from glial cells to Schwann cells)
Surgerical approach:
Middle cranial fossa, translabyrinthine and suboccipital (retrosigmoid)
Reference:
http://radiographics.rsna.org/content/29/7/1955.abstract