Fig. 4. (  A ) Mean survival (z-axis) of C2C12 cells exposed to a range of concentrations of bupivacaine (y-axis) for 2 and 6 h; 1, 2, and 4 days; and 1, 2, and 3 weeks (x-axis). n = 12 for each point; SDs are not shown for the sake of clarity. The color code on the  right reflects the percentage cell survival in the z-axis. Statistical inferences on the data are discussed in the text. (  B ) Effect of 2 days of exposure of a range of bupivacaine concentrations on cell survival. Data are presented as mean with SD. (  C ) Effect of duration of exposure to on cytotoxicity of 0.025% wt/vol bupivacaine. Data are presented as mean with SD.  B and  C are cross-sections of  A .