Scanning Electron Microscopic Observation of the Foetal Labyrinthine Vestibule

Abstract

Vestibular portions of 3 [human] fetal inner ears were examined by scanning electron microscope. The sensory cells from a 14-wk fetus showed a coexistence of hair bundles of different lengths, indicating that the sensory cells were still in the developing stage. An 18-wk fetus showed more developed hair bundles. A distinct kinocilium and unidirectional polarization of sensory cells were clearly seen even in the young short hair bundles. In all fetuses, non-sensory ciliated cells were found located on the vestibular wall between the utricular macula and all 3 cristae ampullares. These ciliated cells seem to disappear with maturation because these cells were not found in other postnatal inner ear specimens examined by the same method.