Anatomy of the petrosphenoidal and petrolingual ligaments at the petrous apex.

The petrous apex is a complex area surrounded by the cavernous sinus, Dorello's canal and Meckel's cave. The petrosphenoidal ligament (PSL) and the petrolingual ligament (PLL) are important structures located in the region. These two ligaments were examined under a surgical microscope in 10 specimens of five adult cadaveric heads fixed in formalin. They were found to span from the petrous apex to the posterior clinoid process, and the lingula of the sphenoid bone, respectively. The dural sleeve of the abducens nerve, the dorsal meningeal artery or its medial branch, and the venous blood space were located below the PSL in all specimens, and the petrous or sphenoidal insertion of the PSL varied in five specimens. The PLL invariably surrounded part of the dorsal and lateral walls of the lacerum segment of the internal carotid artery (ICA), just under the anteroinferior portion of the anteromedial wall of Meckel's cave in all specimens. The PSL and PLL are valuable anatomical landmarks for identifying the ICA and the nerves in this region. A thorough understanding of the relationship of the two ligaments with neurovascular structures is a prerequisite for surgery in and around the petrous apex. (c) 2009 Wiley-Liss, Inc.