Head-Sherrern's Law

HEAD-SHERRERN'S LAW (Head, Sherren) concerning the distribution of sensory disorders following the transection of cutaneous sensory nerves, consists in the fact that light touches and moderate temperatures are not perceived at all, while significant temperature and painful stimuli are perceived paresthetically (sensation of crawling, itching, etc.) and incorrectly localized. The sense of position is disturbed. Sensations of pressure, position, and movement are preserved. Complete superficial anesthesia (except for the sense of pressure, position, movement, and vibration) is noted only in a limited area, approximately determinable for different nerves. Head calls the areas outside the nerve distribution zones intermediary zones. After some time, approximately 7-10 weeks, painful and temperature sensations lose their paresthetic character and are again correctly localized. Complete recovery is often observed only after 1-2 years or later. Thus, deep sensitivity does not suffer at all, protopathic sensitivity recovers quickly and epicritic sensitivity with difficulty (see). In diseases of mixed nerves or simultaneous involvement of muscles and, especially, tendons, deep sensitivity also suffers.