Fig. 2. Axial magnetic resonance images of the spinal canal at each level of the pedicles (L1–S1) in the pregnant and nonpregnant states, respectively. To emphasize our point of view, the images at the L3 level of the pedicles were enlarged. At the L3 level of the pedicles,  white arrows indicate the veins in the ventral epidural site. At each level of the pedicles, the engorged veins cross at the middle of the vertebral level in the pregnant state, but not in the nonpregnant state.