“…I ) wherein the distal end of the nail lifts from the nail bed; at the junction of the nail and nailbed a sawtooth edge may develop as the nails are difficult to clean, leaving an irregular black band under the nail. This sign may also be seen in workers with asbestos or felt and patients with chronic rheumatoid arthritis (Luria and Asper, 1958;Reeve, 1961). It occurs in between 5 and 10 per cent.…”