Ligaments are composed of collagen tissue, connecting portions of two bones to one another. They play a major role in spinal stability and function. Intertransverse ligaments travel between the tips of the transverse processes. Supraspinous ligaments connect the tips of spinous processes to one another. Interspinous ligaments fill the space between adjacent spinous processes and are strong and function mainly in the lumbar region. The anterior longitudinal ligament (stronger) and the posterior longitudinal ligament (weaker) bind the vertebrae and vertebral discs together into a columnar unit. The ligamentum flavum is a band of elastic ligament that connects two adjacent laminae. It becomes one with the facet joint capsule more laterally. [Figure 1] Portions of this ligament must be removed when surgically entering the spinal canal to do a laminectomy for spinal stenosis or to do a smaller laminotomy to remove a herniated disc fragment.
Figure 1: Ligaments of spine, cross-section view