NORMAL SURAL NERVE IN MAN .2. CHANGES IN AXONS AND SCHWANN CELLS DUE TO AGEING

In a combined light and electron microscope study of sural nerves of seven normal individuals, aged between 15 and 59 years, the increase with age in the number of degenerating myelinated fibres is confirmed. Destruction of unmyelinated fibres starting early in life is reported for the first time. The sequence of events in the involution of unmyelinated fibres was found to be the budding of their Schwann cells followed by increasing evidence of their denervation and axonal sprouting. Comments are made on the value of several direct and indirect indices of destruction of nerve fibres. The relevance of denervation and regeneration of fibres in assessing pathological change in slowly progressive disorders of peripheral nerves is emphasised. © 1969 Springer-Verlag.