Hi, Deb,

The extruded disk herniation means that the nucleus pulposus (the material inside the disk) went out through the anulus fibrosus, but the nuclear material remains attached to the intervertebral disk. The herniation is pressing the nerve roots. The thecal sac is made by various nerve roots, because there is no spinal cord in the lumbar area of the spine. In your case the right lumbar root is pressed.

Adomas