The hand is a delicate instrument that is adept both at powerful grip functions and fine, well-coordinated motor movements. The hand also provides vital sensory feedback necessary for control of motor activities.
Besides protective sensibility, providing response to nociceptive and temperature stimuli, the hand has a tactile discriminative function making possible detection of textures and shapes.
As hand sensation is a prerequisite for adequate function, impaired sensibility will severely impact the overall function of the hand.
Hand sensation is based on a complex interplay of mechanoreceptors and free nerve endings in the glabrous skin of the fingers and the somatosensory cortex of the brain.
Various types of mechanoreceptors in the fingertips respond to pressure, vibration or stretching. Long-term exposure to vibration may damage the mechanoreceptors as well as the terminal nerve fibers.
In metabolic neuropathy, such as diabetes, there may be structural and functional alterations in cells and fibers in the nerve trunk. The micro vessels of the nerve may also be impacted.