Since Head's fundamental investigations on certain hyperalgetic cutaneous zones and their relation to affections of deep-seated visceral organs, it is generally accepted that pains located in these organs are transmitted to well-defined areas of the integument. The transmission of these pains is supposed to occur through fibers of the sympathetic nerve originating in the same cord-segments.
While these hyperesthetic zones, up to a short time ago, for want of better knowledge, were considered neurasthenic or hysterical stigmata, Head was the first to establish their anatomic importance as reflex phenomena. He proved conclusively that the location and extension of these hyperesthetic areas as dependent on pains of visceral organs coincided in many instances with the cutaneous eruptive zones of herpes zoster. In other words, by irritation of corresponding segmental fibers of the sympathetic nerve, paresthesias of pain are caused in certain zones of the periphery, which may be followed by the