The intranasal pressure at the opening of the auditory tube was compared by Valsalva's method with that of normal adults under atmospheric pressure to find the auditory tubal function of divers often exposed to hyperbaric conditions.
It was found that the mean auditory tube opening pressure was higher in professional divers than in normal adults who had never been exposed to hyperbaric pressure. There are two ways of accommodating human auditory tubal ventilation: active opening and passive opening-the former is predominant in adults, the latter in children. The function of professional divers resembles the child type. This finding suggested that they were frequently exposed to a hyperbaric environment, and their auditory tube might not be opened and closed with each swallowing movement under atmospheric pressure, or the auditory tube and the middle ear themselves have been changed into a condition whereby they no longer needed the opening with each swallowing movementmight under atmospheric pressure.
Moreover, divers take various postures while they are diving, and in rapid dive, they often take a head-down posture. It was obvious that the auditory tube opens less readily in the head-down position. This phenomenon appears to represent the effect of hydrostatic venous pressure in water.

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Compressed air works have been used as the safest construction work for the basic underground or underwater compressed shield or caisson works in Japan; however, the workers who were exposed to the compressed fields must have put themselves at risk of decompression sickness.
Decompression sickness is generally considered to be due to the bubble effects and the bubbles originate from the supersaturated gas dissolved in the blood and other tissues.
The standard decompression schedule by the Ministry of Labor has been practically applied at the end of compressed air works, and the laborers decompress slowly from the bottom pressure to the surface according to the schedule.
It is difficult to completely prevent the sickness and the average percentage of contracting “bends, ” using the Japanese standard decompression schedule, is considered to be 0.54%. But previous papers reported higher incidences from 1.42 to 3.3% or more.
We have continued an actual investigation on the incidence, and the number of the exposed trials amounted to nearly a hundred thousand. These data were compared between recent five years' group and before.
Eventually, it was ascertained that the incidence has been significantly decreased in the recent five years; however, greater care in occupational safety control is still needed.

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In order to clarify the characteristics of the low-back pain which is prevalent among freight-container tractor drivers, a medical examination, composed of orthopedic tests and questions about health conditions, was carried out on 231 tractor drivers.
Prevailing complaints were: dullness or stiffness of the shoulder (71%); dullness of the neck (69%); dullness of the low back (62%); low-back pain (42%); dullness of the lower limbs (39%) and dullness of the back (36%).
The rates of complaints of dullness or pain of the neck, shoulder, upper limbs, back or lower limbs, and disturbance of daily activity were associated with the grade of low-back pain evaluated from the subjective symptoms.
Orthopedic examination revealed fatigue signs of muscles i.e. tenderness of the body trunk and limbs, tenderness or percussion pain on the spinous processes, and poor results in some tests on muscle strength.
These findings were seen more frequently in the group with subjective symptoms, but even among the group without symptoms, they were evident to some degree.
These findings were considered to originate from the fact that the freight-container tractors had many ergonomic problems and the daily driving hours of many drivers were estimated to exceed the allowable vibration exposure time of the ISO.

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