Fig. 5.  Time course of somatosensory changes after skin incision. (A ) Heat hyperalgesia (HPT) was maximal 1 h after incision and declined continuously afterward. Mechanical hyperalgesia to pinpricks quantified by a reduction of mechanical pain threshold (MPT; B ), an increase of pain ratings to suprathreshold stimuli (mechanical pain sensitivity, MPS; C ) or the area of mechanical hyperalgesia (D ) showed a time course similar to that of heat hyperalgesia but was highly significant across all subjects. Each dot represents either the ratio (B  and C ) or the difference between the injured and the uninjured contralateral site (C ) or the mean radius of the hyperalgesic area (D ). All values except in D  were averaged over a 20-min time window. Mean ± SEM values across 20 subjects. Asterisk =P < 0.05, double asterisk =P < 0.01, triple asterisk =P < 0.001 (post hoc  Scheffé F test).