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. Author manuscript; available in PMC: 2010 Sep 1.
Published in final edited form as: Pain. 2009 Jun 21;145(1-2):96–104. doi: 10.1016/j.pain.2009.05.020

Figure 4.

Figure 4

Effects of muscle injections on sensitivity adjusted pressure pain ratings at the TrapM. Tonic pressure stimuli at the TrapM were adjusted to each individual’s mechanical pain sensitivity to achieve maximal pain ratings of 4.0 ± 0.5 VAS units. Initially, average (SD) pain ratings of sensitivity adjusted tonic shoulder stimuli of NC-PL and NC-LI were 3.9 (0.4) VAS units and 4.0 (0.4) VAS units, respectively (Tonic-start). Similarly, the tonic TrapM pain ratings of FM-PL and FM-LI was 3.9 (0.5) VAS units and 4.6 (0.7) VAS units, respectively. After 30 sec of tonic stimulation (Tonic+30 sec) the shoulder pain of NC-PL and NC-LI participants significantly decreased to 2.4 (1.2) and 1.8 (0.9) VAS units (all p = .001), respectively, but did not statistically change in FM subjects [FM-PL = 4.6 (1.6) and FM-LI = 5.3 (2.0) VAS units (all p > .05)] After lidocaine or placebo injections into TrapMs tonic pressure pain ratings decreased significantly in NC and FM subjects’ [NC-PL = 1.3 (1.3); NC-LI = 0.8 (0.7); FM-PL = 3.24 (2.1); FM-LI = 3.3 (1.9)] (all p < .004). ns = non-significant; TrapM = trapezius muscle.