What are the collection of posterior and anterior roots that occupy the lumbar cistern collectively known as?

Cauda equine-as they descend in the dural sac from their origin from the spinal cord to their exit at their respective intervertebral foramen, the anterior and posterior roots form the caudaequina. The conus medullaris is the most caudal end of the spinal cord, and the filum terminale internum is the strand of pia that extends from the conus caudally to attach to the inneraspect of the dural sac at about s2. The denticulate ligament anchors the spinal cord laterally to the inner surface of the dural sac, and the filum terminale externum anchors the dural sac caudally to the inner aspect of the coccyx.