The distribution of neuroglia and schwann cells in the 8th nerve of man.

The 8th cranial nerve has been dissected from 23 adult temporal bones at autopsy and studied histologically. It was found that neuroglial tissue, continuous with that in the brain stem, supported 8th nerve axons to just beyond the mid-point of the nerve. Lateral to this, axons are supported by Schwann cells and neurilemmal sheaths with a short 'junctional zone' intervening. The point at which the transition occurred, from neuroglial to Schwann cell portions, was medial to the porus in 56 per cent of cases, level with the porus in 18 per cent, and within the internal auditory canal in 26 per cent. The relevance of these findings to some aspects of 8th nerve pathology and surgery is discussed.