Anterior nerve roots (red) and posterior nerve roots (blue) within the dural sac, sectioned longitudinally, as seen in posterior view (a) and lateral view (b)

Three-dimensional (3D) reconstruction of anterior roots (red) and posterior roots (blue). (a) Posterior view without dural sac. (b) Posterior view with dural sac. (c) Lateral view. (a, b) demonstrate that not all dorsal roots may be located specifically behind the anterior nerve roots; as in the central region of the cauda equina, few anterior nerve roots are identified (red)

Anterior view of the distribution of dorsal roots (red) and posterior roots (blue). (a) Nerve roots without dural sac. (b) Nerve roots with dural sac