The effect of denervation on nail growth.

Weir Mitchell (1872) and Sharpey-Schafer (1931) reported that section of a nerve supplying cutaneous fibres to the fingers results in a retardation of nail growth. Head and Sherren (1905), however, believed that the slowing of growth observed in these cases wvas due entirely to the immobilization of the limb either as a result of splinting or paralysis and that division of sensory fibres without limitation of digital movements is not associated with any deficiency in nail growth. According to Bernhardt (1881) "nail growth is relatively independent of the influence of the nerve fibres innervating the fingers and tissues of the nail bed ", though his method of measuring growth from " the upper margin of the epidermis covering the nail root" was open to error. In view of these few and contradictory observations it was decided to investigate nail growth in a series of patients with peripheral nerve injuries. Material and Methods