Abstract
In statistics of workers' accidents under the Compensation Law in Japan, the number of cases of occupational disease due to hand-arm vibration in private enterprises was 2,120 from 1994 to 1997. These consisted of 712 cases (33.6%) by rock drill operation, 372 (17.5%) by chain saw, 323 (15.2%) by pick hammer, 241 (11.4%) by concrete vibrator, 80 (3.8%) by concrete breaker, 61 (2.9%) by bush cutter, 50 (2.4%) by chipping hammer, and 51 (2.4%) by portable grinder, among others. The clinical features of vibration disease differ greatly with the kind of tool. Each tool has its own characteristic of an engineering nature, which, combined with many factors in operation at the workplace, will induce characteristic clinical features. Nine cases from our laboratory cases are discussed in this connection.