Vibration injuries in Norwegian forest workers.

255-263. A free medical examination with compensation for lost earnings was offered to the forest workers in three areas of eastern Norway. Sixty-six per cent attended (413 workers, of whom 296 used chain saws). The prevalence of Raynaud's phenomenon (RP) was 47% in chain saw operators, 14% in forest workers not exposed to vibration, and 9% in 302 indoor workers not exposed to vibration. The high prevalence of RP in chain saw operators was attributed to a traumatic vasospastic disease (TVD). The average time of latency was eight years. The standard symptoms of TVD were attacks of blanching and numbness. Cyanosis and pain occurred rarely. In subsamples, measurements of tactile two-point discrimination and maximal isometric muscle strength (hand grip and finger pressure) as well as x-ray examinations of the wrists and the hands gave no evidence of vibration injury to peripheral nerves, muscles, bones, or joints.