Posterior communicating artery aneurysms (PcomAs) present with oculomotor nerve (OMN) palsy in 20-30% of cases, and the sudden onset of OMN palsy has to raise the suspicion of rupture, until proven otherwise. The surgical technique is described in a stepwise fashion. An illustrative case is reported: a 57-year-old female was admitted to our department with the diagnosis of a right sided-PcomA. Three months before the admission, when she harbored with the acute onset of complete ptosis, diplopia, orbital pain, impairment of the medial, upward, and downward gaze, with no pupil dysfunction. The origin of the Pcom and the neck of the aneurysm were easily identified and the aneurysm was clipped. Then, we followed the OMN and cut for less than 4 mm the above-lying anterior petroclinoid ligament (APL) to obtain nerve release. Although few cases are described in the literature, and ours represents a single case, we support that this maneuver should be introduced in the clinical practice of expert neurosurgeons dealing with vascular pathologies, such as the opening of the falciform ligament occurs for the decompression of the optical nerve.