Background A trans-lateral oropharyngeal wall approach (TLOWA) to the petrous apex has not been previously defined. This study aims to assess the feasibility of a TLOWA for surgical access to the petrous apex and the petroclival region. Methods An endoscopic TLOWA for exposure of the petrous apex and petroclival region was performed on five cadaveric specimens (10 sides). Associated anatomical landmarks were defined, and the strategies for maximal exposure of the internal carotid artery (ICA) were explored. Results Via a TLOWA, the parapharyngeal ICA was widely exposed in all 10 sides. Following transection of the Eustachian tube, the inferior petrous apex and petroclival region could be sufficiently exposed. After drilling the anteroinferior bony canal, the horizontal petrous ICA, foramen lacerum, and the paraclival ICA could be adequately revealed. Conclusion The TLOWA may provide an alternative corridor for access to the petrous apex and the petroclival region. The parapharyngeal, petrous, lower paraclival ICAs, and the foramen lacerum could be adequately exposed via the TLOWA.