抄録
In order to make clear the recent status of vibration hazards among workers belonging to the national forestry bureau in northern Hokkaido, a special health examination was carried out on 417 chain saw operators and 443 bush cutter operators. The results obtained are as follows : 1. Seven point seven percent of chain saw operators and 5.6% of bush cutter operators were diagnosed as suffering from vibration hazards. Distribution of the cases in chain saw operators was 50% in grade I, 31.2% in grade II and 18.8% in grade III, while in bush cutter operators it was 20% in grade I, 60.0% in grade II and 20.0% in grade III. 2. Six new patients were found in this special health examination. 3. Twenty-two of 76 authorized patients, who had been treated with periodical therapy and prohibited from the operation of vibratory tools until this special health examination, were diagnosed as having recovered their health because of the existence of no symptoms concerning vibration hazards. 4. Pains on pressure of the muscles were complained of at the upper arm, forearm, chest and at the back in 12.4% of chain saw and bush cutter operators. Deformities of the elbow, hand and finger joints were recognized in 12.6% of the workers, and ulnar nerve paralysis was recognized in 1.0% of them. 5. Occupational hearing loss and lumbago were diagnosed in 20.2% and 14.7% of the chain saw and bush cutter workers, respectively.
