An intervertebral disc fits between the vertebral bodies and provides a space between the spine bones. The disc normally works like a shock absorber. An intervertebral disc is made of two parts. The center, called the nucleus, is spongy. It provides most of the shock absorption. The nucleus is held in place by the annulus, a series of strong ligament rings surrounding it. Ligaments are strong connective tissues that attach bones to other bones.