Figure 2a. T1-weighted (500/15) sagittal MR images of the cervical spine in (a) extension and (b) flexion. Note the spacious cervical dural canal and presence of wide subarachnoid space ventral to the spinal cord at C5-6 (arrow in a). The posterior dura (arrowhead) has shifted ventrally with flexion of the cervical spine. The epidural plexus is larger and contains multiple flow voids (arrow in b). (c) Contrast-enhanced T1-weighted (500/15) MR image of the cervical spine in flexion shows enhancement of the large posterior epidural plexus (arrows).