Raynaud phenomenon: the Jepson classification.
The Jepson classification of Raynaud phenomenon, based on its pathogenesis, is presented. Raynaud phenomenon can be induced in the fingers of the normal hand as the digital vessels are sensitive to the direct effects of cold. A 'local fault' in the digital arteries renders the fingers more susceptible to a fall of environmental temperature, as do limb artery occlusions which impair the digits' ability to maintain their temperature. Other vasoconstrictive influences act similarly to precipitate the onset of the phenomenon.