<p>Posterior ligamentous complex (PLC) serves as a crucial structural support of the human spine, consisting of the supraspinous ligament (SSL), interspinous ligament (ISL), and ligamentum flavum (LF), with each of these ligaments contributing greatly to limit biomechanical stress. While there is a general agreement on these key components, the literature still varies regarding the inclusion of the intertransverse ligament (ITL) and facet joint (FJ) capsules. Together, these ligaments contribute 30–40% of spinal stability. Preserving the structural and functional integrity of the PLC is essential in surgical planning, as ligaments that are compromised can affect postoperative spinal alignment and load distribution. While it has been revealed that each ligament has unique biomechanical properties, their collective function is essential for distributing mechanical loads and protecting adjacent structures. In this narrative review we offer an in-depth synthesis of the current available literature and offer an essential foundation for clinicians and researchers who aim to study the PLC biomechanical and anatomical function.</p>