Total or partial section of the 8th cranial nerve as a treatment of intractable vertigo has been performed and reported by many neurootologists. Several approaching methods to the cerebellopontine angle(CPA) has been developed and even now under progress. For such a clinical work, it is important to understand the anatomical relationships between the cranial nerves and the anterior inferior cerebellar artery with its tributaries at the CPA, especially around the internal auditory canal. The author observed the anatomy of 52 CPAs using operating microscope in 26 Korean adult cadavers. The obtained results were as follows ; 1) Mostly, the anterior inferior cerebellar artery(AICA) was a single artery(92.3%) passing between the 7th and 8th cranial nerves(50%), and had the nerve-related branches in its meatal segment. 2) The internal auditory artery originated from the meatal segment of AICA and was located between the 7th and 8th cranial nerves in 67.7 and 66.7 percent respectively. 3) The recurrent perforating artery originated from the meatal segment of AICA(44.8%) and passed above the 8th cranial nerve(68.7%), and was located posterosuperiorly to the 7th and 8th cranial nerves. 4) The subarcuate artery mostly originated form the premeatal segment of AICA(55.6%) and passed above the 8th cranial nerve(94.5%), and was located anterosuperiorly to the 7th and 8th cranial nerves in 55.6 percent. 5) At the porus acousticus, the location of the 7th cranial nerve was most commonly anteroinferior(54%) to the 8th cranial nerve. 6) The cochlear-vestibular cleavage plane was discernible in 72 percent. 7) The average dimension from the neural origin to the porus acousticus was 11.32mm(1SD=2.54), and from the porus to the lateral fundus was 8.93mm(ISD=1.34).