The spiral ganglion of the newborn baby.

Four temporal bones of human newborns were studied with light and electron microscopy. In contrast to the adult human spiral ganglion as described by Kimura and coworkers, that of the newborn baby shows no myelination, either of the large ganglion cells or of the small. Whereas in adults the small ganglion cells contain neurofilaments or neurotubules, newborns have no cytoplasmic criteria by which to differentiate large and small neurons. Except for the small neurons, unmyelinated nerve fibers end on the surface of the ganglion cell or they penetrate into the cytoplasm. They form synaptic contacts. It is assumed that they belong to the efferent intraganglionic spiral bundle.