Analysis of trace elements in the human labyrinth by using proton microprobe.

The concentration of zinc in the spiral tract is age-dependent. The accumulation of zinc starts at the bone surface towards the fundus of the internal auditory meatus and continues throughout the whole thickness of the separating wall to reach in advanced age the bone surface towards the basal coil of the cochlea. The concentration of calcium decreases with age. These findings prove our previous histological and densitometric as well as macroscopical investigations of this region.