What does a normal intervertebral disc (IVD) allow?

A normal intervertebral disc facilitates segmental motion, which is essential for the proper functioning of the spine. These discs act as shock absorbers between the vertebrae and allow for movement in various directions, contributing to the overall flexibility of the spinal column. They enable bending, twisting, and other forms of motion while providing support and stability to the vertebral segments.

The anatomy of the intervertebral disc includes the nucleus pulposus, which is the gel-like center, and the annulus fibrosus, which is the tough outer layer. This structure allows the disc to deform under pressure during movement, thus enabling segmental motion without compromising the integrity of the surrounding vertebrae.

In contrast, complete immobility would hinder the flexibility and function of the spine entirely, making it difficult to perform everyday activities. Reduced flexibility suggests limitations in the spine’s motion, which is contrary to the normal function of the intervertebral discs designed precisely to enhance flexibility. Abnormal movement would imply dysfunction or degeneration within the intervertebral disc, potentially leading to pain or other spinal issues, rather than the normal, healthy movement that these discs are meant to support.