Fig. 3. The difference in epidural pressure between the prone and sitting groups. Data are shown as box-and-whisker plots. Cervical epidural pressure in the sitting group was lower than in the prone group (P = 0.005). Box boundaries show 25th to 75th percentiles; lines within boxes indicate medians, whiskers above and below boxes indicate 10th to 90th percentiles, and a dot shows the outlier.