X-ray microanalysis of fluid spaces in the frozen cochlea

The cochlea is quick-frozen and then opened while under liquid nitrogen to expose the scalae of all turns in the mid-modiolar section. Still under liquid nitrogen, the cochlea is transferred to the cold stage of a pre-vacuum chamber especially constructed for attachment to the scanning electron microscope. Under partial vacuum, it is moved to the cold stage in the high vacuum chamber of a field-emission scanning electron microscope. Energy dispersive X-ray analysis demonstrates the relative levels of sodium, potassium, and chlorine in the fluid spaces of the cochlea.