Fig. 1From: Quantification of muscle tone by using shear wave velocity during an anaesthetic induction: a prospective observational studyChanges in shear wave velocity during anesthetic induction. The gray circles represent means and the bars represent standard deviations. At the opioid-induce rigidity, the velocity was faster than that at the baseline. At the complete muscle relaxation, the velocity was slower than that at the baseline. **p < 0.01 versus baseline conditionBack to article page