ABSTRACT
The anatomy of the cerebellopontine angle (CPA) was described in great detail several years ago by Rhoton (1). Briefly, theCPAcistern is bounded laterally by thepetrous face,medially by the pons, and superiorly by the tentorium cerebelli (2). The cerebellopontine fissure opensmedially and has superior and inferior limbs that meet at a lateral apex. Cranial nerves IV through XI are located near or within the angular space between the two limbs commonly referred to as the CPA (1). The superior cerebellar artery and anteroinferior cerebellar artery (AICA) both arise from the basilar artery and course through theCPA cistern (3). Veins from the pons,middle cerebellar peduncle, and cerebellopontine fissure unite near the trigeminal nerve and form the superior petrous veins (4).
