Background <p>The skull base ligaments have been extensively studied in the literature due to their clinical and surgical significance. The posterior petroclinoid fold (PPCNF) and petroclival ligament (PCVL) are two adjacent structures that have barely been studied and are frequently confused. The present study uses an innovative classification system to investigate the PPCNF and PCVL ossification patterns.</p> Materials <p>An archive of 164 computed tomography (CT) scans (328 sides) was evaluated. The sexes were distributed as follows: 86 females and 78 males. The mean age was 47.78 ± 15.64 years old. The ossification patterns were classified as follows: Type 0 (no ossification), Type 1 (incomplete ossification), Type 2 (complete ossification). The incomplete ossification was further classified as subtype 1a (ossification from the clival region), subtype 1b (ossification from the petrous region), and subtype 1c (ossification from both regions).</p> Results <p>No PPCNF ossification was observed in 72.6% (238/328 sides). Incomplete PPCNF ossification was identified in 25.8% (85/328 sides), and complete ossification in 1.5% (5/328 sides). A male predominance was determined for the PPCNF ossification. No PCVL ossification was observed in 85.4% (280/328 sides). Incomplete PCVL ossification was observed in 8.2% (27/328 sides) and complete ossification in 6.4% (21/328 sides). The age affected the PCVL ossification, with the older patients presenting with ossification. Simultaneous absence of PPCNF and PCVL ossification was observed in 215 sides (65.5%). The coexistence of incomplete PPCNF and PCVL ossified variants was identified in 13 sides (4%). Concomitant complete PPCNF and PCVL ossified variants were detected in 2 sides (0.6%).</p> Conclusions <p>The current study presents a detailed description of the PPCNF and PCVL. Knowledge of both structures’ ossification is important for anatomists, radiologists, and clinicians due to their close relationship with neurovascular structures.</p>