The internal auditory artery: (embryology, anatomy, angiography, pathology).

A review of the literature on the embryology, anatomy and angiography of the internal auditory artery has shown that there may be considerable variation as to the origin and number of internal auditory arteries. The present study, based on serial magnification angiographies of the internal auditory artery, has demonstrated 7 variants of the origin of this artery although in 45.4% of cases the internal auditory artery arose from the anterior inferior cerebellar artery. For the diagnosis of pathological processes in the cerebellopontine angle (tumors, sudden deafness, vascular abnormalities) magnification angiography is of special importance. Acoustic neurinomas in particular can be diagnosed early on the basis of vascular dislocations and possible tumor staining. Magnification angiography is the method of choice for the demonstration of vascular malformations. The etiology of sudden deafness can not be determined by angiographic studies alone, due to the fact that the internal auditory artery can show considerable variations as regards length and caliber. Magnification angiography of this region should be carried out in all cases with the clinical picture of a cerebellopontine angle lesion in order to achieve diagnostic clarification.