OPLL - Ossified Posterior Longitudinal Ligament

Posterior longitudinal ligament, is a straight continuous band of ligament running along the posterior part of vertebral bodies. 

A similar ligamentous band connecting the vertebral bodies anteriorly is known as Anterior Longitudinal ligament. 

The posterior longitudinal ligament (Peach colour) continues superiorly as the Tectorial Membrane stabilizing the CV junction. 

The anterior longitudinal ligament is shown in blue line in the above image. 

This PLL ( posterior longitudinal ligament) can undergo degenrative changes with age and there is ossification which occurs within the ligament. 

It's called ossified PLL and not calcified as Haversian Canal systems and ossification process is seen on histopathological analysis. 

This ossified PLL also known as OPLL is a common cause of Cervical Myelopathy in the elderly population. 

It can be of 4 main types :

When the symptoms are significant the patients require surgery. 

Laminectomy and decompression of spinal cord. 

The laminae are removed in an attempt to widen the spinal canal and overcome the anteriror compression.