Distribution of arteries from brain stem to inner ear around the internal auditory canal.

In the present work, casts of vessels surrounding the internal auditory canal of the guinea pig were subjected to scanning electron microscopic examination. Most casts were prepared by the resin-casting method using Mercox resin. The following results were obtained: 1) Individual variations and bilateral asymmetry were observed in the anterior inferior cerebellar artery (AICA), which branches off the basilar artery (BA); 2) Frequently a loop the AICA was found in the CP-angle and internal auditory canal; 3) The internal auditory artery (IAA) did not always originate in AICA but sometimes arose directly from BA; 4) In common cochlear artery and anterior vestibular artery, there were individual differences and asymmetric branching patterns on both sides; 5) We conclude that inner ear disease of vascular origin may be influenced by individual variations in the BA and its branches.