Explanation:
The posterior longitudinal ligament runs along the posterior aspect of the vertebral bodies inside the spinal canal. It forms the anterior boundary of the spinal canal and contributes to spinal stability. The ligament limits excessive spinal flexion and helps contain disc material. Herniated discs often protrude posterolaterally because the ligament is thinner laterally. Degeneration or ossification of this ligament can cause spinal canal stenosis. Understanding spinal ligament anatomy is essential for interpreting spinal pathology. Reference: White AA. "Clinical Biomechanics of the Spine." Lippincott Williams & Wilkins, 1990.