Motion Segment

The motion segment is the basic functional unit of the spine and consists of two adjacent vertebrae, the intervertebral disc, and the ligaments that hold them together. The facet joints of the vertebrae and the surrounding muscles that support movement also participate. This segment allows movements such as flexion, extension, and rotation, while at the same time ensuring the stability of the spine. Its proper function is essential for normal mobility and load absorption. Disorders of the motion segment may lead to pain or stiffness.