The sympathetic system and pain.

The term "sympathetically maintained pain" does not imply that the pains are due to the sympathetic system. It is not a matter of excessive or decreased sympathetic activity. The extreme sensitivity and hyperpathia are removed by blocking the sympathetic supply, also when the lesion is central to the blocked region. Therefore the hyperpathic state may be considered as an abnormal state passed from neurone to neurone trans-synaptically, both from periphery to central nervous system and vice versa. This fact suggests that we are not concerned primarily with abnormal states induced by the sympathetic system, but with a general kind of abnormality of the total nervous system. This phenomenon may be relieved by removal of the sympathetic nerves to the relevant neurons of the periphery.