Occupational cervicobrachial disorder and its causative factors.

Occupational cervicobrachial disorder often diagnosed as cervicobrachial syndrome, cervical syndrome, or thoracic outlet syndrome has been frequently noticed among workers of the offices and factories in Japan since about 1955. Based on the data of case reports and mass examinations, the prevalence and the causative factors of the disease are described. The factors provoking the disorder can be divided into two categories, i.e, the ways how the workers use the musculature and strain the nerous system and the conditions in which the job is organized into the work system and is controlled. Studies on bank note counting, copying-slips writing, machine sewing, and amplifier assembling work reveal that not only the high density of the task but also time factors such as long work spells and lack of voluntary rests are important in causation of the disorder. Results of health examinations of 117 female workers on a cigarette assembly line confirm a close relation between the clinical severity of the occupational disorder and the subjective complaints at work and at home. The manifestation of clinical symptoms depends on what kinds of the first category factors predominate, but the progress to severer cases is relevant to the work system hampering the recovery from chronic muscular and central fatigue.