Fig. 2

Differences in pain intensity between groups; a immediate pain; b 6 h after the IM injection; and c 24 h after the IM injection. Statistically significant differences on pain intensity were found between anesthesia and no-anesthesia groups regardless of the needle size (long 19G with anesthesia vs. long 19G without anesthesia, p < 0.001; and short 21G with anesthesia vs. short 21G without anesthesia, p = 0.015)