Language

PathophysiologyWhen we touch an item or a texture, the sensory impulses from the hand are transmitted to the sensory cortex in the brain via nerve trunks in the hand and the spinal cord.

Vibrations from a hand-held vibrating tool are transferred to the hand where they may have a detrimental effect on mechanoreceptors, nerve fibres, blood vessels and muscles. In the nerves, intraneural oedemas may occur as well as damage to myelin sheaths and nerve fibres may be damaged. 

High frequency vibrations may exert their effect distally in the fingers while low frequency vibrations may be transmitted proximally in the arm.

The walls of blood vessels may be subject to and functional changes that may influence microcirculation and induce a tendency for vasospasm – so called ”white fingers”.

In muscle tissue, there may be degenerative as well as regenerative cellular changes, while the brain cortex may suffer from functional reorganisation resulting in an overlap of cortical areas corresponding to individual fingers.

All individuals are not equally susceptible to vibrations. Some individuals can work most of their life without developing problems while others may develop symptoms already after a few years. The reason is probably biological, but factors such as the type of tools, working methods and exposure time are also important.

Once a vibration injury has occurred, there is no effective treatment available. Therefore, prophylactic measures are essential, and methods to detect the earliest signs are of the essence so that occupational and environmental hazards can be eliminated.