Volumetric and Dimensional Analysis of the Guinea Pig Inner Ear

Abstract

The objective of this study was to provide accurate volumetric data on the fluid spaces and soft tissue in the guinea pig inner ear by measuring all histologic serial sections by means of Metamorph Imaging Software at 400× to 1,000× magnification. The total endolymph volume of the inner ear was 4.691 mm³, of which 1.501 mm³ was in the cochlea, 3.090 mm³ in the vestibular labyrinth, and 0.100 mm³ in the endolymphatic duct and sac. The total perilymph volume was 15.938 mm³, of which 8.867 mm³ was in the cochlea and 7.071 mm³ in the vestibular labyrinth. The volume of the organ of Corti per millimeter length increased toward the apex, but the volumes of the stria vascularis, spiral ligament, and spiral limbus decreased. The volume of the macula utriculi was larger than that of the macula sacculi. The measurement of the luminal surface area of the stria vascularis was 3.944 mm², and that of the vestibular dark cells was 5.772 mm².