[The stria vascularis of the inner ear and its normal structural variations].

The ultrastructural effects of gentamicin on the stria vascularis of the inner ear of guinea pigs were studied by transmission electron microscopy. In a single specimen of an isolated, inner ear we found an unexpected variation in the structure of the stria vascularis in a normal, pigmented, guinea pig not treated with ototoxic drugs. There were prominent, wide protrusions from the apical surfaces of marginal cells into the endolymphatic space. This finding has not been previously reported and was seen in only 1 of 7 animals studied. It may be considered a normal structural variation, and is not pathological change in the stria vascularis due to ototoxic drugs.