The herniated disc has several anatomic forms: contained, extruded, and free fragment (sequestered disc). These descriptions serve to explain the relationship of the herniation to the the disc located between the vertebral bodies. The diagrams above show the different types of herniation. A Contained Disc Herniation (1) stretches the outer wall (black semicircle) but is still bound by the outer wall. An Extruded Disc Herniation (2) breaks through the outer wall and ligament but is in contact with the disc space. A Free Fragment (3) breaks through the outer wall and ligament and is completely separated from the disc.