Posterior longitudinal ligament (PLL)

This is a thin ligament which lies behind the vertebral bodies and discs.  Degenerative changes in the spine may cause this structure to become thickened, (hypertrophy of the Posterior longitudinal ligament (PLL)) or even calcified (Ossification of the posterior longitudinal ligament (OPLL)).  Enlargement of the posterior longitudinal ligament (PLL) may result in Spinal canal stenosis (or narrowing) with compression of the spinal cord or nerve roots.